yum update
Loaded plugins: fastestmirror, ovl
Determining fastest mirrors
Could not retrieve mirrorlist http://mirrorlist.centos.org/?release=7&arch=x86_64&repo=os&infra=container error was
14: curl#6 - "Could not resolve host: mirrorlist.centos.org; Unknown error"
One of the configured repositories failed (Unknown),
and yum doesn't have enough cached data to continue. At this point the onl........
Have you got this error from Apache?
[notice] suEXEC mechanism enabled (wrapper: /usr/sbin/suexec)
[error] (28)No space left on device: Cannot create SSLMutex
At first glance it appears that you may be out of disk space but the issue is ipc or interprocess communication.
This will clear out the ipcs processes so things can work, this often happens during high traffic and may be a sign of DDOS.
The command below will fix it, it will list al........
Even today we see a lot of servers that have different services and ports open for rpc and this creates not only potential inward vulnerabilities but perhaps more common, the abuse of your network resources in reflective rpc queries.
To stop this problem, you should disable and remove all services relating to rpc or at least block all relevant ports for the service.
Surprisingly, there are still some providers and OS installs in Linux that install these services and leave them........
Let's say you have a directory /mnt/raid which has files and directories inside it, but nothing is mounted to it.
Then you mount a block device such as /dev/sdh to /mnt/raid
Even though /mnt/raid has files and directories there, you can only see the mounted contents of /mnt/raid.
How do we access the original contents?
Just do a bind mount of the root filesystem to another location.
mkdir /bindmount
mount --bind / /b........
The issue is when you need to echo something as root/sudo, that it doesn't work. You can never do a sudo echo to an output file as you'd expect.
Take an example to clear out wasted RAM buffers/cache like this:
sudo echo 1 > /proc/sys/vm/drop_caches
-bash: /proc/sys/vm/drop_caches: Permission denied
The solution is to run tee as sudo/root
What we do is echo 1, but then pipe it to the "tee" command as sudo........
In a lot of distros like Debian, ecryptfs will mount itself in /home/yourusername/Private
This is controlled by Private.mnt which may contain the mount path like this:
/home/yourusername/Private
Change the default mount location of ecryptfs by modifying this file:
home/.ecryptfs/yourusername/.ecryptfs/Private.mnt
After you unmount and relogin, you should find ecryptfs is now mo........
This seems to have changed for RHEL 8 where a normal dracut to update your initramfs creates a system that only boots for the running kernel. For example if you have Kernel 5 and then chroot into a RHEL 8 variant which uses kernel 4.18, and run dracut, it seems that by default the system will be unbootable.
It is also the case that if you move your RAID array or drives to another server that it will be unbootable, because dracut seems to only include modules needed for the curre........
So say you happen to have 2 NICs of the exact same chipset, they will generally show up as the same name, with possibly a different revision in lspci. Normally this is not an issue if you have a server with 4 NICs, generally the eth0 to eth3 appears from left to the right (or right to left on some vendors) so it doesn't take much figuring out.
Generally if you have different chipsets for different NICs, it should be easy to know which one is eth0 or the first NIC in the OS.........
Later versions of ls try to be helpful and smart to prevent errors in dealing with files with spaces that were tradtionally a pain.
However if you need the raw/real filenames, this can break scripts or if you are pasting into a csv etc....
How do you make ls not add the quotes?
Add the capital "-N" switch
ls -N
You could also add an alias to make it more permanent
Do this to add it to ~/........
You probably didn't do an "update-grub" and grub no longer has any proper menu entries, but before you can fix it let's try to get grub booting anyway.
If you get this lovely black grub screen here's how you can get things booting.
In my case I have a gpt partition with partition 1 and 2. Partion 1 is just my EFI / ESPand partion 2 /dev/sda2 is my root which includes /boot.
You will have to adjust this if you had a separate /boot partition.........
I've seen this bizarrely happen on a newly partitioned and custom installed Linux install, particularly if you did not properly unmount before rebooting.
You can find reports of it happening on various
How to fix the error: invalid arch-independent ELF magic.
You need to boot into Live/Rescue mode, chroot into your OS properly and then do a grub-install on each drive that nee........
If you are doing a custom deployment and image, make sure that when you rsync'd or tar'd that you didn't mess up the symlnk of /etc/mtab to /proc/self/mounts
ln --force -s /proc/self/mounts /etc/mtab
Will fix this........
This article about migrating to a CentOS 7 /8 RAID mdadm array has a lot of info but I wanted to focus specifically on what newer versions of CentOS 7 require to boot mdadm and what changes are necessary on CentOS 7.8+
CentOS 7 / 8 mdadm RAID booting requirements
This assumes you are chrooting into an existing install or using it to get a new deployment ready. However, these steps can........
Are you getting this error in CentOS 8 when trying to use yum to install a package?
Error: Failed to download metadata for repo 'appstream': Cannot prepare internal mirrorlist: No URLs in mirrorlist
What we need to do is not use the automatic mirror list and manually set the base URL
Solution
sed -i 's/mirrorlist/#mirrorlist/g' /etc/yum.repos.d/CentOS*
sed -i 's%#baseurl=http://mirror.centos.org%baseurl=........
A quick fix is to run this command:
sudo brctl setageing br0 0
This causes the aging of the MAC address to time out immediately or in 0 seconds, which delete the entry frmo the FDB (Forwarding Database) and causes the error to go away. The default time is 300 seconds or 5 minutes.
You can also add it under your br0 definition like this in /etc/network/interfaces to make it permanent and automatic:
auto br........
Debian based OS's have a similar issue as the behavior in RHEL/CentOS dhclient, which is that if you have an interface that relies on DHCP, if the first attempt fails, it will quit and stop. This is a problem especially if you are using your Linux as a router or something else mission critical, but where the internet for some reason may have been down or the DHCP server it gets a lease from broken.
The expected behavior you would hope is that when things are back online that the........
This may be necessary if you have a VM or if for some reason you just want to be more efficient with your space and have the flexibility of changing your swap space at will.
What we mean is the ability to use a "swap file" or similar to the Windows "pagefile" that normally resides on the root or c: partition of Windows.
Here's all you have to do and then you to can have a single partiton with everything, including the swap file on the root partition if you........
The Best Docker Tutorial for Beginners
We quickly explain the basic Docker concepts and show you how to do the most common tasks from starting your first container, to making custom images, a Docker Swarm Cluster Tutorial, docker compose and Docker buildfiles.........
A lot of newer installs will automatically prohibit the root user from logging in directly, for security reasons or they will only allow key based access.
If you know what you are doing/don't care about security or have an incredibly secure password for testing, then you can enable it.
Edit this file: /etc/ssh/sshd_config
Find the following line: PermitRootLogin
Set it like this:
PermitRootLogin yes
Now rest........
From the terminal do this:
cat /proc/cpuinfo|grep -E "svm|vmx"
You should get output like this(svm = AMD-v and vmx=Intel-VTx):
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx pdpe1gb rdtscp lm constant_tsc arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc cpuid aperfmperf pni pclmulqd........
If you get this error, you were probably compiling some sort of binary or package and got this error. It is normally solved by installing the "gettext"package.
On Debian/Ubuntu just apt-get it:
apt-get install gettext
After that you should be able to configure and make (compile) properly.........
The problem seems to be that whatever kernel and initrd you have is tied to an old version of CentOS 7 that is no longer in the current repos of most mirrors.
If you were previously able to PXEboot and install CentOS and you are sure your network and tftp are good the problem is that you have an outdated kernel and initramfs that point to a defunct version.........
yum update
Loaded plugins: fastestmirror
Setting up Install Process
Determining fastest mirrors
YumRepo Error: All mirror URLs are not using ftp, http[s] or file.
Eg. Invalid release/repo/arch combination/
removing mirrorlist with no valid mirrors: /var/cache/yum/x86_64/6/base/mirrorlist.txt
Error: Cannot find a valid baseurl for repo: base
You have mail in /var/spool/mail/root
........
To disable selinux temporarily and immediately:
setenforce 0
To make it permanent edit /etc/selinux/config:
vi /etc/selinux/config........
The below appears at first to be a bad mirror DNS error, but if you've ruled that out you just need to clear your broken yum cache and things will be good.
yum update
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
* base: centos.01link.hk
* extras: centos.01link.hk
* updates: centos.01link.hk
http://mirror.worria.com/centos/7.8.2003/os/x86_64/repodata/repomd.xml: [Errno 14] HTTP Error 404 - Not........
The best way to avoid this problem is to understand how your BIOS is setup to boot.
Often newer machines will default to U(EFI) which is different than the traditional MBR/Legacy mode.
The problem is that this may not be apparent, often a BIOS Boot Menu will show a Legacy Boot Option and EFIOption without defining it.
A good example of this is if your USB is called "Kingston" you may see in your Boot Menu "Kingston" and also "Ubuntu"........
This assumes your system is a fresh and normally working install.
What often happens is that many new devices have multiple audio outputs which are generally analog and HDMI/Digital out. Sometimes the OS defaults to the wrong one that you didn't want.
For example if your sound is supposed to play over the HDMI, perhaps the output is set to analog or vice versa.........
This happens to a lot of Nvidia users especially users of newer cards like the RTX series. If for example you are trying to boot and install Linux and you get a black and white grub2 screen instead of a nice graphical welcome installer, you probably suffer from this bug. It is normally followed by the user booting and finding they just have a blank/black screen.
Here is the quick flow of steps to fix it:
If you get a black grub scree........
This seems to happen on most if not all Nvidia cards but the good news is that if you are using any of the Linux drivers and have the nvidia-settings tool installed it is just a simple command.
Solution:
nvidia-settings --assign CurrentMetaMode="nvidia-auto-select +0+0 { ForceFullCompositionPipeline = On }"
Enter the above command in your terminal and the screentearing will be fixed which is like enabling Tear Free on AMD cards.&........
/usr/libexec/qemu-kvm -enable-kvm -boot order=cd,once=dc -vga cirrus -m 4096 -drive file=~/23815135.img,if=virtio -usbdevice tablet -net nic,macaddr=DE:AD:BE:EF:D4:AB -netdev bridge,br=br0,id=net0
qemu-kvm: -usbdevice tablet: '-usbdevice' is deprecated, please use '-device usb-...' instead
access denied by acl file
qemu-kvm: bridge helper failed
[root@CentOS-82-64-minimal 23815135]# /usr/libexec/qemu-kvm -enable-kvm -boot order=cd,once=dc -vga cirrus -........
http://vault.centos.org/5.9/os/i386/repodata/filelists.xml.gz: [Errno -1] Metadata file does not match checksum
yum clean all
yum makecache
yum update........
yum -y install gcc make gperf genisoimage flex bison ncurses ncurses-devel pcre-devel augeas-devel augeas readline-devel
checking for cpio... cpio
checking for gperf... no
configure: error: gperf must be installed
configure: error: Package requirements (augeas >= 1.2.0) were not met:
Requested 'augeas >= 1.2.0' but version of augeas is 1.0.0
yum remove augeas augeas-libs augeas-devel
wget http://downl........
chroot /root/kvmguests/4591915/mount
FATAL: kernel too old
This happens for example if you are in Centos 6 and trying to chroot into a system based on a newer kernel like 4.x+
You'll have to use a newer OS/kernel system to chroot into the environment or a VM running a newer kernel.........
Unless you are using OpenStack, AWS etc then cloud-init is just some bloat that slows down the booting of your VMand can actually halt it from booting if it doesn't have a proper working IP (not good!).
#remove cloud init!
Debian based Ubuntu / Mint
sudo apt remove cloud-init
RHEL / CentOS based
yum remove cloud-init
........
Most newer distros inexplicably cause your NIC to have what Icall "random" non-standard name conventions because of systemd.
This is a big problem for many people and especially those running servers. Imagine that you have a static IPconfigured for ens33 but then the hard disk is moved to a newer system, the NIC could be anything from ens33 to enp0s1, meaning that manual intervention is required to go and update the NIC config file (eg. /etc/network/interfa........
yum -y install wget unzip
wget https://download.nextcloud.com/server/releases/nextcloud-18.0.2.zip
unzip nextcloud-18.0.2.zip
yum -y install php php-mysqlnd php-json php-zip php-dom php-xml php-libxml php-mbstring php-gd mysql mysql-server
Last metadata expiration check: 0:58:02 ago on Fri 13 Mar 2020 02:12:49 PM EDT.
Dependencies resolved.
===================================================================........
There are a few caveats that may not be obvious to everyone so I am going to cover them here but keep this in mind before starting.
Before starting install epel or you will be missing tesseract:
yum -y install epel-release
#1) When you specify your SSL certificate with a full path, it really needs to exist where you tell it to (including the default location of /etc/ssl/certs and /etc/ssl/c........
Mar 22 13:46:14 box named[31767]: validating @0x7f51bc001550: . DNSKEY: unable to find a DNSKEY which verifies the DNSKEY RRset and also matches a trusted key for '.'
Mar 22 13:46:14 box named[31767]: validating @0x7f51bc001550: . DNSKEY: please check the 'trusted-keys' for '.' in named.conf.
Mar 22 13:46:14 box named[31767]: error (broken trust chain) resolving './NS/IN': 192.36.148.17#53
One possibility is sometimes that your time is ou........
This is only really necessary in the case you don't want DHCP. If you are dealing with an encrypted LUKS server on the internet, you will often want to have a static IP so you know which IP to connect to (or if you have a semi-static IP assigned by DHCP).
SET IP Address by /etc/initramfs-tools/initramfs.conf
IP Address=192.168.1.27
Gateway=192.168.1.1
Subnet Mask: 255.255.255.0
Hostname=myhome.com
IP=192.1........
Yes you have that right, the network service in RHEL8 / CentOS 8 / Rocky Linux / Alma Linux no longer exists. So there is no more systemctl restart network
You can restart NetworkManager but it doesn't have the same effect or ifup/ifdown on all interfaces.
Generally if NetworkManager is installed you will want to restart it or it won't apply the settings from ifcfg.
systemctl restart NetworkManager
To repl........
The cool thing here is that we only need 1 drive to make a RAID 10 or RAID 1 array, we just tell the Linux mdadm utility that the other drive is "missing" and we can then add our original drive to the array after booting into our new RAID array.
Step#1 Install tools we need
yum -y install mdadm rsync
Step #2 Create your partitions on the drive that will be our RAID array
Here I assume it is /dev........
In this case I am executing using "python3" but what you find in cases like this can be surprising.
The most common issues are that someone has a module for python 2 "pip" and doesn't realize they need "pip3" to install it for python3, but this is not one of those cases.
ModuleNotFoundError: No module named 'bs4'
OKmaybe we didn't install it for python3?
[........
This is a gotcha but be aware sometimes iptables may be active and loaded by default.
Also make sure you don't just disable firewalld but also stop it otherwise it will still block stuff:
systemctl stop firewalld
If the above is not the issue then it is possible iptables is running and blocking stuff too, so you'll need to stop iptables.
So in addition to opening firewalld or disabling it, you would need to disable iptables........
mysql reset root password.
Oops I can't remember my MySQL root password!
[root@centos7test etc]# mysql -u root -p
Enter password:
ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: YES)
First we need to stop mariadb:
systemctl stop mariadb
Now we need to restart it with skip-grant-tables whic........
yum -y install mariadb-server
systemctl start mariadb
mysql_secure_installation
Now we need to secure our install and set the MariaDB root password:
The lines you need to act on are marked in bold shown with the answer you need.
mysql_secure_installation
NOTE: RUNNING ALL PARTS OF THIS SCRIPT IS RECOMMENDED FOR ALL MariaDB
SER........
yum install centos-release-scl
yum install rh-php72 rh-php72-php rh-php72-php-mysqlnd
Symlink PHP binary:
ln -s /opt/rh/rh-php72/root/usr/bin/php /usr/bin/php
Symlink Apache and PHP module config:
ln -s /opt/rh/httpd24/root/etc/httpd/conf.d/rh-php72-php.conf /etc/httpd/conf.d/
ln -s /opt/rh/httpd24/root/etc/httpd/conf.modules.d/15-rh-php........
Use fdisk on your USB drive to create a bootable NTFS partition (in my case /dev/sdb):
sudo fdisk /dev/sdb
Welcome to fdisk (util-linux 2.27.1).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.
Command (m for help): n
Partition type
p primary (0 primary, 0 extended, 4 free)........
This is all controlled by /etc/issue
You can basically enter anything in there that you like, but there are preset variables that are mentioned at the end of the page that discuss this.
Some examples of /etc/issue:
Centos 7:
S
Kernel r on an m
Ubuntu 16.04:
Ubuntu 16.04.6 LTS n l
You can also insert any of t........
It is very silly but the default on the ifup-eth script tells dhclient ( the program that obtains a DHCP IPaddress if you have selected DHCPin your ifcfg-eth* config file) to EXIT / QUIT if the first attempt to obtain a lease fails.
No amount of dhclient.conf settings will fix this because if dhclient is started with -1 (which it is by default)then dhclient will quit.
This is obviously very bad for MOST cases. Say for example you have a power outage or........
yum install iptables-services
systemctl enable iptables
service iptables save
iptables: Saving firewall rules to /etc/sysconfig/iptables:[ OK ]........
By default at least on Centos 7 nfs only allows 8 connections and starts 8 nfsd daemons.
To fix this edit this file:/etc/sysconfig/nfs
Edit the line "RPCNFSDCOUNT" (uncomment it so it looks like this:
RPCNFSDCOUNT=30
In the example above we are setting 30 nfsd daemons to run (or in other words 30 connections are possible this way).........
In Centos 7 tftpd will not work with selinux. Clients will not be able to connect and this is all you'll see in the log (then nothing more):
Sep 18 14:39:15 localhost xinetd[4327]: START: tftp pid=4331 from=192.168.1.65
On the client/computer side you will see this:
TFTP.
PXE-M0F: Exiting Intel Boot Agent
Basically the client is being instantly connected and bloc........
By default printscreen or alt print screen will get the whole desktop or the application in focus, respectively. But what if you want to select a portion of the screen?
gnome-screenshot:
ksnapshot
compiz
This is a nicely integrated solution
sudo apt-get install compizconfig-s........
Install Errors on Version 12:
This error happened on QEMU emulator version 2.11.1 pve-qemu-kvm_2.11.1-5
on Proxmox/Debian but installing on QEMU.12 on Centos 6 did not produce the error.
*Update it is not related to the OS or QEMU version. This happened in Centos 6 too after a second install.
What really causes this even though you successfully install........
This is usually because of STP causing a delay in the negotiation.
Edit your ifcfg script eg:
/etc/sysconfig/network-scripts/ifcfg-eth0
Add a LINKDELAY of 30 seconds or whatever works for you:
LINKDELAY=30
After that you should have an IP during bootup.........
If you don't aleady have it, you'll need EPEL
Install LXC
yum -y install lxc lxc-templates
Loaded plugins: fastestmirror
Setting up Install Process
Loading mirror speeds from cached hostfile
* base: mirror.it.ubc.ca
* epel: mirrors.kernel.org
* extras: mirror.it.ubc.ca
* updates:........
Do you hate how Centos 7 defaults to allocating most of your valuable space to /home even though it is a production server?
Here is a quick guide on how to take back that space live, while online (of course make sure you have backups just in case something goes wrong!):
First we will reduce our home dir by 100G:
lvreduce -L -100G /dev/mapper/centos-home
WARNING: Reducing active and open logical volume to ........
lvreduce -L -100G /dev/mapper/centos-home
Do you really want to reduce centos/home? [y/n]: y
Size of logical volume centos/home changed from ........
This should apply to most Linux distributions just incase you get into trouble or wipe out the defaults by accident.
/etc/iproute2/rt_tables
#
# reserved values
#
255 local
254 main
253 default
0 unspec
#
# local
#
#1 inr.ruhep........
Set this in /etc/sysctl.conf
net.ipv6.conf.all.disable_ipv6 = 1
#apply the settings
sudo sysctl -p
........
First we need to create dhclient.conf if it doesn't exist or edit it:
vi /etc/dhclient/dhclient.conf
#add this line at the top add the IPs as commas they will be the highest priority nameservers and whatever your ISP gives you will be used after these one (good for DNS backup)
prepend domain-name-servers 127.0.0.1,10.10.25.8;
After you restart your network or run dhclient again you should see the contents of........
initiator = client
target = server
These are the first concepts you should understand which is that in iscsi essentially the "initiator" is the client and the "target" is the server.
iSCSI is derived from the old fashioned SCSI that us oldtimers grew to love. The "i" stands for Internet and the SCSI stands for "Small Computers Systems Interface" (SCSI).
iSCSI Target (Server)Setup
targetcli is the pac........
function centos7 {
release=`cat /etc/redhat-release|awk '{print $4}'|grep ^[7]`
if [ "$release" != "" ]; then
centos7='yes'
fi
}
centos7
echo "$centos7"
We create a function called "centos7" and then call it by just typing "centos7"
We then access a variable that may be set........
PHP Warning: PHP Startup: Unable to load dynamic library '/usr/lib64/php/modules/pdo_mysql.so' - /usr/lib64/php/modules/pdo_mysql.so: symbol mysql_options, version libmysqlclient_18 not defined in file libmysqlclient.so.18 with link time reference in Unknown on line 0
#not sure what is wrong with php-mysql but I removed it and installed mysqlnd
yum -y remove php-mysql
yum -y install php-mysqlnd........
mytop is one of my favorite tools and it is fairly simple aside from a few caveats and issues that persist to this day.
To install it on Centos:
yum -y install centos
Configure ~/.mytop
vi ~/.mytop
user=root
host=localhost
db=test
#port=3306
socket=/var/lib/mysql/mysql.sock
header=1
color=1
Try runni........
systemd is like the service manager for your Centos and other modern Linux distributions (including Debian/Mint/Ubuntu) allows you to enable services, stop them, restart them, check their status and even reboot your system.
The key commands or arguments you will use with systemctl are the following:
Unit Commands:
list-units [PATTERN...] List loaded units
&nbs........
Getting an error about gi missing when running a .py python script?
Just install EPEL and install the python3-gobject package:
yum install python34-gobject........
Did you just install the minimal version by accident or want to install the GUI? No need to reinstall just tell yum to do the work for you!
You could actually have both installed and choose one as your preference on demand (although many people prefer GNOME's simplicity).
Step 1.)
Install Gnome and/or KDE.
To install the GNOME Desktop on Centos 7:
yum -y groups install "GNOME Desktop"
To........
zenity is a nice utility as part of the gnome window manager that allows you to script from bash and retrieve the input from the user. It could also be helpful in just notifying a user when they login with a popup window.
I'll give an overview of what's available with zenity:
Application Options:
--calendar Display calendar dialog
--entry Display tex........
To remove all spaces from all files in the current directory
linux rename remove spaces
rename "s/ //g" *
how to replace part of the text with another (it is almost like using sed):
rename s/"Screenshot at 2019-04-22 "/"AC97-Windows-InstallSolution"/g *
The first part "Screenshot at 2019-04-22" is what we're looking for
The........
https://yarnpkg.com/lang/en/docs/install/#centos-stable
curl --silent --location https://dl.yarnpkg.com/rpm/yarn.repo | tee /etc/yum.repos.d/yarn.repo
If you need node.js:
curl --silent --location https://rpm.nodesource.com/setup_6.x | bash - yum install nodejs yarn........
Server Side Config
1.) First install nfs-utils
yum -y install nfs-utils
2.) Configure nfs share
Create a directory for your NFS share
mkdir /datastore
Create your NFS share in /etc/exports
echo "/datastore 10.220.101.0/24(rw,sync,no_root_squash)" >> /etc/exports
systemctl restart nfs........
Centos when copying old files and restarting it seems load everything fine and then says [FAILED] with no log or other message.
service restart named
named [FAILED]
Check more thoroughly you may have missed the error if you have lots of zones!
service named restart|grep error
zone 1.168.192.in-addr.arpa/IN: not loaded due to errors.
zone 2.168.192.in-addr.arpa/IN: no........
Internal Server Error
The server encountered an internal error or misconfiguration and was unable to complete your request.
Please contact the server administrator, root@localhost and inform them of the time the error occurred, and anything you might have done that may have caused the error.
More information about this error may be available in the server error log.
Apache/2.2.15 (CentOS) Server at testdomain.com Port 80........
ValueError: new value non-existent xfs filesystem is not valid as a default fs type
Pane is dead
From what Iread this is misleading and has to do with the fact that the initrd and kernel are mismatched.
This is a hard situation because for some older hardware Iam using the Centos Plus kernel which has modules that Irequire for an older server/NIC. This seems to have cropped up in the past few months and there is no simple fix........
It looks like this has something to do with APIC but I am not sure. I have similar CPUs with a different MB and BIOS that work fine on the same type of kernel. A lot of time the issue is because of the C-step setting in the BIOS.
The same thing happened on the 2.6 kernel with Centos 6 but this is a homebrew 4.4 kernel soI am not sure why it is happening when even Centos 7 (3.2) kernel works OK.
Solution - It comes down to the BIOS set........
This works for almost all ISO's Ifind (at least Linux based):
sudo dd if=CentOS-6.9-x86_64-minimal.iso of=/dev/sdg bs=20M
20+1 records in
20+1 records out
427819008 bytes (428 MB) copied, 118.233 s, 3.6 MB/s
Of course change the .iso filename above and the /dev/sdg to your desired USB drive!........
curl: (35) Unknown SSL protocol error in connection
The main solution is to update curl and nss. If you are having an issue with curl through Apache/PHPyou will need to restart PHPafter.
It's important to remember that this error could mean a lot of things but most often it simply means that curl and openssl may be outdated and only allow newer secure ways of connecting to SSL.
In general here is how you would fix it in most c........
Getting this error on Centos 6 with PHP 5.3 when just running "php -v"
PHP Warning: PHP Startup: Unable to load dynamic library '/usr/lib64/php/modules/module.so' - /usr/lib64/php/modules/module.so: cannot open shared object file: No such file or directory in Unknown on line 0
PHP Warning: Cannot load module 'XCache' because conflicting module 'apc' is already loaded in Unknown on line 0
Solution:........
This guide will work for most modern Linux versions like Centos RHEL 7, Debian, Mint, Ubuntu etc...
In Centos 7 the days of editing the "kernel"line and adding "single"are gone. On top of that sometimes after a new install passwords do not work, maybe you forgot your password or for some other reason you need to break in or fix your system? It could also be because you can't mount your root / or some other /etc/fstab error and many other err........
This happened on Centos for no apparent reason with no obvious issue in the logs. Data could be read fine but not written (possibly due to some corruption or out of memory issue in the OpenVZ container is the best guess).
All mysql update and insert queries failed freezing without any error log on any database and table.
Tried to restart:
service mysqld restart
Timeout error occurred trying to stop MySQL........
Centos 6 requires GLIBC 2.12 however a lot of new programs you would want to compile may need a newer glibc. You can't remove the old glibc since the whole OS is based on it but you can install the updated glibc alongside it and do an export pointing to your updated GLIBC.
mkdir ~/glibc_install; cd ~/glibc_install
wget http://ftp.gnu.org/gnu/glibc/glibc-2.14.tar.gz........
Install requirements:
yum -y install gmp-devel mpfr-devel libmpc-devel glibc-devel glibc-devel.i686 zip unzip jar
Download, untar, configure, compile and install GCC
http://mirrors.kernel.org/gnu/gcc/gcc-5.5.0/gcc-5.5.0.tar.gz
tar -zxvf gcc-5.5.0.tar.gz
cd gcc-5.5.0
./configure
make
make install
Now you need to cleanup th........
This is important as unfortunately Centos may designate a package obsolete and the replacement breaks everything (eg. you have a config file and the new replacement is not at all compatible with it and it breaks your application).
This is where disabling obsoletes comes into play, it can be done from yum but it doesn't work at the time I find.
yum --setopt=obsoletes=0 install someapp However Ifind it still installs the new app and not the one you ask for........
You are using Centos 5 which is deprecated so nothing in yum will work until you follow this post to use the vault:
http://realtechtalk.com/Centos_59_Working_Vault_Repo_file-1921-articles
yum update
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
* epel: fedora-archive.ip-connect.vn.ua
Traceback........
Centos 5 is not supported running yum will produce an error like this:
YumRepo Error: All mirror URLs are not using ftp, http[s] or file.
Eg. Invalid release/
removing mirrorlist with no valid mirrors: /var/cache/yum/base/mirrorlist.txt
Error: Cannot find a valid baseurl for repo: base
Solution - Update this file CentOS-Base.repo
# CentOS-Base.repo........
Just a note before you do this you should have a sure, guaranteed way into the system such as local, KVMor preferably publickey making bruteforce SSH absolutely impossible since there is no password to bruteforce and even if someone knew the password they wouldn't be able to login except from the local console (presumably you should make sure no one unauthorized has physical access).
1. Edit /etc/ssh/sshd_config
Find the section like this:........
Iam not sure why this is happening neither the hostnode or VM changed. All I did was reboot the hostnode and startup the Centos VM again, also note it happened with the original kernel on the VM and also the latest 6.9 kernel as of this writing as shown below.
Host Node: Centos 6.9
Kernel:2.6.32-696.6.3.el6.x86_64
Kernel: 2.6.32-042stab123.9
Same result in any kernel above........
Some guides still use the old Centos 6 style (do not use /etc/sysconfig/network).
In Centos 7 the file is /etc/hostname
echo "HOSTNAME=yourhostname.com" > /etc/hostname........
Done on Centos 7.3 very important as clearly based on older guides it was a lot easier and more simpler! Hint do not use grub2-install!
If you have trouble booting after this check this CentOS mdadm RAID booting/fixing guide.
One huge caveat if you are an oldschool user or sysadmin who has avoided UEFIbooting
The nor........
This error is usually because of some sort of encryption in this case a Seagate enclosure with encryption (even though not enabled) did not allow this hard drive to boot.........
I am using a GTX 1060 but replace the download for the driver with the correct/current version for your particular card by visiting: http://www.nvidia.com/Download/index.aspx?lang=en-us
yum install automake curl openssl-devel libcurl-devel gcc gcc-c++
yum -y install kernel-devel-`uname -r`
yum -y install unzip
#the........
This is mainly the case on Centos but applies to other distros and situations. If you are running programs in the background with the &, at least in Centos it is usually not honored and if you quit or are disconnected the backgrounded programs will be sent sighup and be shut down.
The simplest way around this instead of using & is to start any programs or commands with "nohup"
Eg.
nohup yourscript.sh........
I was sure this was a Centos bug with OpenSSL, Apache, MySQL or even PHP. I tried everything but nothing helped. One clue is that if you check the Apache logs you will see nothing in the access logs until minutes later (this means Firefox has not even passed your request to the remote Apache/htttpd server).
When even accepting the invalid certificate message that would show up minutes later when trying to "View the Certificate" Firefox would freeze. This bu........
Using Apache 2.2 and PHP5.6 PHPBB3 is very slow to respond. Actually for some reason it takes so long to even register a log entry in access_log as in several seconds or a few minutes later it shows up in Apache. All other vhosts and Apache access stops working and freezes until the request to access PHPBB3 slowly completes.
It seems to randomly be slow if you stop using it whether for posting or reading the forums. I've migrated to different machines including........
Centos 7 is no cakewalk, there are many fundamental features and basic utilities that are missing or even completely renamed or different!
Another shocking thing is to check your NIC it is set by default to not turn on when booting!
And by the way there is no more standard eth0 the NIC convention is now "enp0s3"
vi /etc/sysconfig/network-scripts/ifcfg-enp0s3........
tar -xvJf somefile.tar.xz
It is very annoying that so many are now using the .xz archive format as standard instead of .tar.gz but nevertheless above is how you would extract it with the "J" flag (not lower case j as that is for bz).........
In short the two drives in the array were /dev/sdd and /dev/sde. The kernel sees they were unplugged and have gone down as you can see below.
mdadm caught the first one being unplugged /dev/sde and disabled the missing drive. However when the final drive that was part of the array is unplugged it didn't notice at all. Instead it complains about an IO error later for drives that the kernel knows do not exist anymore.
[45817.162728] ata4: exception........
Add this to the .htaccess file
#right/working:
AddType application/x-httpd-php .html .htm
#wrong (won't work in many cases):
AddHandler application/x-httpd-php5 .html .htm........
Could not retrieve mirrorlist http://mirrorlist.centos.org/?release=6&arch=x86_64&repo=os error was
12: Timeout on http://mirrorlist.centos.org/?release=6&arch=x86_64&repo=os: (28, 'Operation too slow. Less than 1 bytes/sec transfered the last 30 seconds')
Error: Cannot find a valid baseurl for repo: base
You would think this should be fine and simple like using a proxy with most other software?
However........
Get the python "warc extractor" from here. WARC just seems to be such an unnecessary and complicated format. Why not use tar, rar, zip etc...?
./warc-extractor.py -dump content !http:content-type:pdf yourfile.warc........
[Thu Jan 26 14:13:31 2017] [notice] caught SIGTERM, shutting down
[Thu Jan 26 14:14:00 2017] [notice] suEXEC mechanism enabled (wrapper: /usr/sbin/suexec)
[Thu Jan 26 14:14:00 2017] [error] Server certificate is expired: 'Server-Cert'
[Thu Jan 26 14:14:00 2017] [notice] SSL FIPS mode disabled
[Thu Jan 26 14:14:07 2017] [notice] suEXEC mechanism enabled (wrapper: /usr/sbin/suexec)
[Thu Jan 26 14:14:07 2017] [error] Server certificate is expired: 'Server-Ce........
Many users still are not aware but simply patching OpenSSL does not secure you against many known and easy to exploit attacks that will render your encryption useless by an attacker.
Use the following setings in /etc/httpd/conf.d/ssl.conf
SSLCipherSuite "EECDH+ECDSA+AESGCM EECDH+aRSA+AESGCM EECDH+ECDSA+SHA384 EECDH+ECDSA+SHA256 EECDH+aRSA+SHA384 EECDH+aRSA+SHA256 EECDH EDH+aRSA !CAMELLIA !SEED !3DES !RC4 !aNULL !eNULL !LOW !MD5 !EXP !PSK !........
Disclaimer, before starting this I do not like ioncube, it is great to protect your source code, but a big pain to setup this extension since it has to be done manually. Further, fi you do a PHPupdate ioncube may no longer work, causing important sites or services to not work (I wish authors would take another approach).
1.) Download from here:https://www.ioncube.com/loaders.php
2.) Extract the contents and co........
forcedeth 0000:00:08.0: irq 25 for MSI/MSI-X
forcedeth 0000:00:08.0: eth0: MSI enabled
forcedeth 0000:00:08.0: eth0: no link during initialization
ADDRCONF(NETDEV_UP): eth0: link is not ready
forcedeth 0000:00:08.0: eth0: link up
ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready
Dec 1 18:21:32 box15 kernel: forcedeth: Reverse Engineered nForce ethernet driver. Version 0.64.
Dec 1 18:21:32 box15 kernel........
If you want to make sure only a certain IP can access your server for any service or protocol here is a way to do it (just be sure you have access to the IP(s) mentioned or you will be locked out).
iptables -F
iptables -A INPUT -i lo -j ACCEPT
iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
iptables -A INPUT -p tcp -s IP.IP.IP.IP -j ACCEPT
iptables -A INPUT -j DROP
serv........
md127 issue, it should be /dev/md3 per mdadm.conf
Any time something is mounted as md127 it almost always means there is no entry for this mdadm array in the mdadm.conf in initramfs (which is separate from your actual /etc/mdadm.conf).
cat /etc/mdadm.conf
ARRAY /dev/md3 metadata=1.2 UUID=b6722845:381cc94e:7a2c5b5f:8e3b7c4f
The reason for this is something strange, most Linux OS's bizarrely always keep their own copy of /etc/mdadm.con........
vzkernel-2.6.32-042stab116.2.x86_64.rpm&n........
We've all done this at some point, you work on the wrong shell window and this was my first time making this mistake but I deleted a partition table in fdisk, recreated it and saved it with "wq" and even ran partprobe! If you haven't rebooted yet then you can still recover your partition table, otherwise you're in big trouble.
Fortunately since it was a live system and in use the kernel still had to use the old table like below:........
migrating from an old OpenVZ (Centos 5) to new OpenVZ (Centos 6)
Also if migrating from 32-bit HN to 64-bit your RAM will probably be much bigger than it should be!
16x bigger
eg. 32bit HN:
total used free shared buffers cached
Mem:&nb........
You may get this after a long time of not rebooting but especially if you have rsync'd a / partition or deployed an image to another VPS or computer, you will often have this issue.
The good thing it usually just takes a reboot.
Here is more info from Centos........
Stopping httpd: [ OK ]
Starting httpd: [Wed Jun 29 19:29:44 2016] [warn] _default_ VirtualHost overlap on port 80, the first has precedence
[Wed Jun 29 19:29:44 2016] [warn] _default_ VirtualHost overlap on........
Usually the cause is inexplicable because some things just don't work correctly even when calling all commands by their full path.
Usually adding the following to your crontab file at the top will fix/solve the issue:
SHELL=/bin/sh
PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin
........
pip install obfsproxy
/usr/lib/python2.6/site-packages/pip/_vendor/requests/packages/urllib3/util/ssl_.py:90: InsecurePlatformWarning: A true SSLContext object is not available. This prevents urllib3 from configuring SSL appropriately and may cause certain SSL connections to fail. For more information, see https://urllib3.readthedocs.org/en/latest/security.html#insecureplatformwarning.
InsecurePlatformWarning
You are using pip version 7.1.0, however version 8.1.1 i........
There was a problem importing one of the Python modules
required to run yum. The error leading to this problem was:
No module named yum
Please install a package which provides this module, or
verify that the module is installed correctly.
It's possible that the above module doesn't match the
current version of Python, which is:
2.7.9 (default, Apr 21 2016, 16:51:58)
[GCC 4.4.7 20120313........
This is using find and -mtime in Centos Linux, it simply takes "n" (which is a day) as a number and you can specifiy a + or - to say older or less than a certain age.
# (show everything older than 1 day)
find . -mtime +1
........
Stopping httpd: [FAILED]
Starting httpd: httpd: Syntax error on line 73 of /etc/httpd/conf/httpd.conf: Cannot load /etc/httpd/modules/mod_file_cache.so into server: /etc/httpd/modules/mod_file_cache.so: cannot open shared obje........
I got this when running yum on a Centos 6 machine:
Error: database disk image is malformed
It was easily fixed with the following command:
yum clean all........
The following assumes the computer is local/physical to you and/or it always has a LANIP so it can be accessed on site without having a default gateway.
The key to this is not to set a default gateway for your computer or you can set a script on boot or other time to delete the gateway (where eth0 is the NIC you are using):
route del default eth0
50.80.20.2 is the VPN server you connect to
192.168.1.1 is your........
Add the following to fstab where 192.168.1.125/Media is the samba share and where /home/homeuser/Downloads is where you want to mount.
Change user and pass to what is needed (if no pass is required it still works fine with the below).
//192.168.1.125/Media /home/homeuser/Downloads cifs user=guest,pass=bla 0 0
mount: wrong fs type, bad option, bad superblock on //192.168.1.125/Media,
&nbs........
This is actually very simple and this example assumes your network device is "eth0"
In Centos your network config would be the following: /etc/sysconfig/network-scripts/ifcfg-eth0
Take the same path and just add a "-range0"
So to add a range create the following file: /etc/sysconfig/network-scripts/ifcfg-eth0-range0
IPADDR_START=192.168.1.50
IPADD........
grub> root (hd0,0)
root (hd0,0)
Filesystem type is ext2fs, partition type 0xfd
grub> setup (hd0)
setup (hd0)
But if you do:
root (hd1,0)
setup (hd1)
it does work, I think hd0/sda had a GPT partition that was not removed properly (what I did was just dd bs=512 count=1 the partition table from another drive since the partition table should be identical).
Checking if "/boot/grub/........
Say you have a bunch of files like this:
file-01.jpg
file-02.jpg
...............
What if you want to mass rename them?
the rename tool can work just like sed
For Debian based distros:
Note "file" is what we search for and "newname" is what we replace it with, so substitute according to your requirements.
rename s/file/newname/ name-file-*.jpg
For R........
In this case we want to mount partition #2
fdisk -lu Centos-6.6-x86_64.img
You must set cylinders.
You can do this from the extra functions menu.
Disk Centos-6.6-x86_64.img: 0 MB, 0 bytes
255 heads, 63 sectors/track, 0 cylinders, total 0 sectors
Units = sectors of 1 * 512 = 512 bytes
Device Boot&nbs........
It sounds like this is corrected in later versions of the OpenVZ kernel but Iam not sure, it may also be that a much newer kernel is needed and Centos may not have a recent enough kernel.
*Debain 7.0 however does work fine as a temporary fix or work around.
Debian 8 OpenVZ no IP and networking not working:
lo Link encap:Local Loopback
 ........
In this example we have 2 drives in a RAID array and /dev/sdb is the one that failed. /dev/sda1 is also the /boot partition which we tell grub to install on /dev/sdb eg install root (hd0,0) /dev/sda1 on the new drive /dev/sdb (hd1)
First copy the partition table from /dev/sda to /dev/sdb
dd if=/dev/sda of=/dev/sdb bs=512 count=1
Run partprobe to detect the new partition table
partprobe........
Here is the scenario you or a client have a remote machine that was installed as a standard/default minimal Centos 6.x machine on a single disk with LVM for whatever reason. Often many people do not know how to install it to a RAID array so it is common to have this problem and why reinstall if you don't need to? In some cases on a remote system you can't easily reinstall without physical or KVM access.
So in this case you add a second physical or disk or already ha........
In my case I could login with the initial install but I rsync'd everything over while preserving ownership and permissions to another RAID partition and booted from that.was fine before. The problem is that you are kicked out the second you login and the problem was SELINUX for some reason (perhaps it noticed something strange when it was moved to the new partition)
login: pam_unix(login:session): session opened for user root by LOGIN(uid=0)
login: ROOT LOG........
#solution
Edit /etc/yum.repos.d/openvz.repo
For the first two entries comment out #mirrorlist and uncomment #baseurl and then it worked
openvz yum problem Centos 6.5 cannot find file on mirror:
yum update
Loaded plugins: fastestmirror
Determining fastest mirrors
* openvz-kernel-rhel6: mirrors.ustc.edu.cn
* openvz-utils: mirrors.ustc.edu.cn
base ........
I never did get it working, it is too bad as obfsproxy should really be an option and integrated into the OpenVPN client and server or something similar:
yum -y install python-pip python-devel
No package python-pip available.
#install the EPEL repo
python-pip install obfsproxy
python-pip install obfsproxy
-bash: python-pip: command not found
pip install obfsproxy
&........
[Errno 14] PYCURL ERROR 22 - "The requested URL returned error: 404 Not Found"
The above happened when for some reason all the mirrors in my cache didn't have the files (some mirrors only keep the latest version of Centos).
Itried to block them all but that didn't help because it seemed the mirrors were all hardcoded no matter what I tried.
Here is how to fix it and reset your mirror list in Centos
cd /var/cac........
[Tue Jun 23 02:05:52 2015] [error] Unable to configure RSA server private key
[Tue Jun 23 02:05:52 2015] [error] SSL Library Error: 185073780 error:0B080074:x509 certificate routines:X509_check_private_key:key values mismatch
The above is an accurate description of what is wrong.
In our case the client made a simple mistake of thinking the localhost.crt and localhost.key (default key locations for Apache SSL in Centos) were in the same directory but they we........
#from epel repo
yum -y install opendkim
chkconfig opendkim on
cd /etc/opendkim/keys
opendkim-genkey -vd mail.server.com
opendkim-genkey: generating private key
opendkim-genkey: private key written to default.private
opendkim-genkey: extracting public key
opendkim-genkey: DNS TXT record written to default.txt
........
yum -y install dvdauthor ffmpeg mjpegtools sox bc
rpm -ivh dvd-slideshow-0.8.4-2.noarch.rpm
Preparing... ########################################### [100%]
1:dvd-slideshow ########################################### [100%]
/usr/bin/dir2slideshow: line 553: bc: command not f........
It looks like newer versions of Centos no longer have encfs so you have to compile it, only it does not work and fails so those wanting encfs should probably use any other OS which supports it better.........
You need the "openssh-clients" package which contains sftp and scp.
yum -y install openssh-clients........
I messed up the bootloader by accident on a standard Centos 6.3 install because I turned the /dev/vda1 boot partition into an mdadm raid 1. This was all done correctly aside from one point Ididn't realize was an issue metadata=00.90 is the only thing that will allow you to boot (otherwise grub won't work and you won't boot).
So the next step is rescue mode from a CD right? The problem you will find is that grub does not detect your hard drives, this is Ibelieve is be........
It's a basic script that reads the file "ips.txt" in the current directory and then creates a corresponding ifcfg file
#!/bin/bash
GATEWAY=192.168.1.1
NETMASK=255.255.255.0
device=eth0
counter=0
for ips in `cat ips.txt`; do........
cc: Internal error: Killed (program cc1)
Please submit a full bug report.
See for instructions.
make: *** [ext/fileinfo/libmagic/apprentice.lo] Error 1
make: *** Waiting for unfinished jobs....
Stopping crond: ........
wget http://ftp.gnu.org/gnu/bash/bash-4.3.tar.gz
tar xzvf bash-4.3.tar.gz
cd bash-4.3/
wget --no-directories --level 1 --recursive http://ftp.gnu.org/gnu/bash/bash-4.3-patches/
for patch in `ls bash43-*|grep -v .sig$`; do
echo applying "$patch"
patch -p0 < $patch
done
./configure;make;make install
#it will install to /usr/bin/bash but if your bash is somewhere else you need to overwrite the old one.........
yum -y install mathtools
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
* base: centos.mirror.rafal.ca
* epel: mirror.steadfast.net
* extras: mirror.agmn.ca
* rpmforge: repoforge.mirror.constant.com
* updates: centosb5.centos.org
extras ........
This can happen when you install RPMForge or other repos with the wrong architecture and here's how you fix it (simply uninstalling won't usually fix it):
solution
yum clean all
yum -y install openvpn
Loaded plugins: fastestmirror, presto
Loading mirror speeds from cached hostfile
* base: mirror.its.sfu.ca
* extras: centos.mirror.nexicom.net
* rpmforge: mirror.cpsc.ucalgary.ca
* up........
yum -y install wget
wget -P /etc/yum.repos.d/ http://ftp.openvz.org/openvz.repo
rpm --import http://ftp.openvz.org/RPM-GPG-Key-OpenVZ
yum -y install vzkernel vzctl
After that just reboot and you may also have to enable ip_forward in /etc/sysctl.conf........
Error: Package: php-Monolog-dynamo-1.7.0-1.el6.noarch (epel)
Requires: php-aws-sdk
Error: php-pecl-zendopcache conflicts with 1:php-eaccelerator-0.9.6.1-1.el6.x86_64
Error: php-xcache conflicts with php-pecl-apc-3.1.9-2.el6.x86_64
Error: php-pecl-zendopcache conflicts with php-pecl-apc-3.1.9-2.el6.x86_64
Error: Package: php-horde-Horde-Vfs-2.1.2-2.el6.noarch (epel)
&n........
kernel:[735188.961824] Kernel panic - not syncing: Fatal exception in interrupt
Write failed: Broken pipe
I'm not sure what is causing this and have never seen it on any server before.........
It's not as simple as "yum install" as you can see below and it doesn't stop there.
yum install php53
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
* rpmforge: mirror.us.leaseweb.net
* extras: centos.mirror.rafal.ca
* updates: centos.mirror.nexicom.net
* base: centos.mirror.nexicom.net
* addons: centos.mirror.nexicom.net
Setting up Install Process........
Kernel panic - not syncing: Attempted to kill init!
Pid: 1, comm: init Not tained: 3.2.51-3.el6.x86_64 #1
Call Trace:
panic+0x8c/0x1a2
forget_original_parent+0x34d/0x360
exit_notify+0x12/0x140
do_exit+0x1d8/0x400
do_group_exit_+0x50/0xc0
sys_exit_group+0x12/0x20
system_call_fastpath+0x16/0x1b
panic occurred, switching back to text console........
This is different than Centos 5, you have two services btu they are called "smb" and "nmb".
You need to enable and start "nmb" in order for your samba server to be listed.
chkconfig nmb on; chkconfig smb on
service nmb start;service smb start........
./configure
./configure: cannot locate gcc 3.x. please install it or specify with --qemu-cc
yum -y install gcc make
./configure
./configure: cannot locate gcc 3.x. please install it or specify with --qemu-cc
yum -y install compat-gcc-*
./configure
Error: Could not find alsa
Make sure to have the alsa libs and headers installed.
yum -y install alsa-lib-devel
./configure........
On the same OS with the same kernels basically I cannot boot FreeBSD installer, I believe the issue is the host CPU.
One host runs an Intel and works, while an Opteron 2373 does not work despite suggestions from this thread: http://149.20.54.209/showthread.php?t=36761
I've tried cpu options like "kvm64" "Opteron_G3" and none........
Linux box13. 2.6.32-042stab076.5 #1 SMP Mon Mar 18 20:41:34 MSK 2013 x86_64 x86_64 x86_64 GNU/Linux
even setting privvmpages to a specific setting DOES not affect "free -m" in containers.
This is probably a kernel issue
23:36:29 up 159 days, 7:12, 4 users, load average: 0.42, 0.44, 0.33
[root@box13 ~]# free -m
total&n........
rpm --import http://apt.sw.be/RPM-GPG-KEY.dag.txt
i686:
rpm -ivh http://packages.sw.be/rpmforge-release/rpmforge-release-0.5.2-2.el6.rf.i686.rpm
x64:
rpm -ivh http://packages.sw.be/rpmforge-release/rpmforge-release-0.5.2-2.el6.rf.x86_64.rpm
........
http://fedoraproject.org/wiki/EPEL#How_can_I_use_these_extra_packages.3F
Visit the above URL, choose your version and architecture and install it. EPELhas a lot of missing and extra packages that rpmforge does not.
For old versions of EPEL that are deprecated, eg.........
Everyone should be running with safe_mode on in /etc/php.ini (on Centos) as it makes exploiting your system more difficult is PHPcan't execute anything on the system if a script is exploited.
For example with Safe_Mode on the only executable files on the system are ones in the safe_mode_exec_dir = /safephp
This is crucial, if you must execute anything from PHPthen you have to copy the binary and assign to the user that Apache runs your site under.&........
PHP5 Centos 6 displays part of code from PHP file for some scripts
Solution
edit /etc/php.ini change short_open_tag = Off to:
short_open_tag = On
Then restart Apache and it should be resolved (assuming the scripts failing used )
........
I flashed an LSI Logic firmware to it and it broke the BIOS (cannot do Ctrl+R) for booting purposes but allows other functionality to work normally.
I tried downgrading to a Dell firmware for Perc 6i but it won't work, not even with MegaCli
wget http://downloads.dell.com/FOLDER00416606M/1/SAS-RAID_Firmware_W83M2_LN32_6.3.1-0003_A14.BIN
--2013-08-26 12:53:39-- http://downloads.dell.com/FOLDER00416606M/1/SAS-RAID_Firmware_W83M2_LN32_6.3.1-0003_A14.BIN
Resolvi........
rpm --import http://apt.sw.be/RPM-GPG-KEY.dag.txt
rpm -ivh http://packages.sw.be/rpmforge-release/rpmforge-release-0.5.2-2.el6.rf.x86_64.rpm
Retrieving http://packages.sw.be/rpmforge-release/rpmforge-release-0.5.2-2.el6.rf.x86_64.rpm
Preparing... ########################################### [100%]
1:rpmforge-release #############........
pxe-32 tftp open timeout
The solution was to enable tftp in xinetd with "chkconfig tftp on".
See the troubleshooting below:
chkconfig --list
NetworkManager 0:off 1:off 2:off 3:off 4:off 5:off 6:off
acpid 0:off&n........
iptables -t nat -A PREROUTING -p udp -m multiport --dports 20,123,443 -j REDIRECT --to-port 53
getsockopt failed strangely: Invalid argument........
The solution is strange but simple and works each time on Centos:
yum downgrade libtorrent........
The key here is to use the "uuencode" command but note that we specify the file name twice (this must be done at least on Centos or it won\'t work).
The first file.zip is the actual file we want to send.
The second file.zip i........
pecl install apc........
When trying to reboot this Centos 5 container, it gets stuck as "mounted" and requires a manual start command, here is what dmesg shows:
[424458.173252] VE10000: no allowed mount options found for device 0:21
[424458.177970] proc: unrecognized mount option "relatime" or missing value
[424460.297663] CT: 10000: stopped
[426663.466433] CT: 10000: started........
After some fsck issues I can't boot my Centos 6.4, this just keeps repeating over and over.
init: tty (/dev/tty2) main process (1031) terminated with status 1
init: tty (/dev/tty2) main process ended, respawning
Disabling SELinux through Single User mode fixed this.........
flush privileges;
ERROR 1146 (42S02): Table ‘mysql.servers’ doesn’t exist
This happened to me on a system running Centos with the REMI repo and a new version of Mysql 5 (which the official Centos/RHEL does not support on version 5).
The solution is just to run this program "mysql_upgrade", after that flush privileges will work.
mysql_upgrade........
After booting the net install, eg. over tftp here's the format you need to install the OS when it asks for the URL:
http://mirror.centos.org/centos-6/6.4/os/x86_64/
Obviously change the URL and path to match the architecture and version that you're looking for and you'll be good to go.........
Solution To The Following:
yum -y install zlib-devel
yum -y install e2fsprogs*
*** Cannot find /usr/include/et/com_err.h. (yum install libcom_err-devel) ***
Installation didn't pass, halting install.
Once requirements are met, run the following to continue the install:
cd /usr/local/directadmin/scripts
./install.sh
Common pre-install commands:
http://help.directadmin.com/it........
Step #1 - Create Wrapper Script
vi /usr/local/bin/phpsendmail
#!/usr/bin/php
........
02:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168B PCI Express Gigabit Ethernet controller (rev 03)
For whatever reason it seems the r8169 driver that ships and has shipped with most Linux distros for years is still flawed and does not work properly on these cards, causing 100mbit connectivity when it should be 1gbit and even worse, causing random network dropouts. The r8169 driver in Linux kernels is simply not meant to be used on th........
This seems to be a verified bug on KVM with no solution. I wasn't able to get through the installer with Ubuntu 12.04, it would crash while "configuring apt". I was able to install it with Ubuntu 12.10 but it crashes randomly at times.
This happens with the latest Centos 6.3 kernel and KVM package, I even compiled the latest version from the KVM website and used that, but the results are still the same.
Here's some links to discussion about the bugs:........
This booting error is because the Xen PV guest image uses the Xen kernel, this is not compatible with anything but a host running a Xen kernel.
I did a kpartx -av virtual.img and then it created some partitions that showed up in fdisk.
I mounted it and did a chroot into it and removed the xen kernel and installed a normal kernel but Xen still shows the same kernel in Grub (only the Xen one).
This is strange but it seems like this Xen PV guest has some sort of hidden or........
This is something I often setup for clients because it's very helpful for people in datacenters, this allows custom OS installs on demand, you can customize it more by using kickstart etc.. but here's a base I use before customizing more:
This little script below will install everything you need to get booting by PXE Linux.
It also assumes you set a local IP (be sure not to overwrite your existing IP) on eth0:0 (note the :0) as 192.168.1.10 and it........
Here is a quick script that works on most Centos versions to disable the virus/SELinux from blocking basic functionality.
The first echo 0 statement disables SELinux instantly but it will still be enabled on reboot.
The second line disables it permanently.
#!/bin/bash
#disable SELinux Immediately
echo 0 > /selinux/enforce
#disable SELinux Permanently
sed -i 's/SELINUX=enforcing/SELINUX=disabled/g' /etc/selinux/config........
qemu-img create -b centos.5-8.x86.20120308.qcow2 -f qcow2 ../kvmguests/25000-centos5.8x86.qcow2
Formatting '../kvmguests/25000-centos5.8x86.qcow2', fmt=qcow2, backing_file=centos.5-8.x86.20120308.qcow2, size=10485760 kB
-b the source/base image
-f format is qcow2 and the location of the destination image
What is so special about this? It's even quicker than creating a template with OpenVZ but this is an actual OS.
It saves time a........
For whatever reason the current OpenVZ yum repo file enables the RHEL6 version of OpenVZ, why is this bad? Because if you're running Centos 5 it still defaults to using the kernel from RHEL6 which won't work on RHEL5/Centos 5.
Ionly realized this after wondering why I couldn't boot into OpenVZ that it was using one meant for RHEL6.
To fix the problem you have to edit /etc/yum.repos.d/openvz.repo and disable the "[openvz-kernel-rhel6]" section by changing........
ip tunnel add tun3 mode gre remote 192.58.1.5 ttl 64
ioctl: no such device
I solved this on Centos by loading the ip_gre module:
modprobe ip_gre
On Debian I believe it is the "sit" module.........
ip_conntrack: table full, dropping packet.
A lot of clients I've seen have this issue, it really seems the default level is way too small. Once this connection tracking table becomes full then packets get dropped which is obviously a bad thing.
One thing to be mindful of though is that 350 bytes of memory are used per entry so there is some justification for not keeping it too high. However, if you have multiple servers running or high traffic daemons........
A lot of people become nervous (and understandably so) when checking their auth or security logs, in Centos /var/log/secure and see dozens, hundreds of even thousands of attempted logins to various services, especially SSH.
Of course you could manually block these people/IPs but no one has time to read the logs like that, what if some program or script could do it for you?
This is what denyhosts does for you, it checks the logs and based on a certain number of failed SSH attem........
This may sound silly but there will be conflicts/issues with the default Centos repository so you have to use a third party like remi (I prefer not to do this but it's the only option unless you migrate your sites/data to another server or can stand some downtime-not an option IMHOon a production server).
You may need to upgrade to PHP5.3 to run Joomla or many other reasons.
Your host needs to use PHP 5.2.4 or higher to run this version of Jo........
ntpd[7047]: can't open /var/lib/ntp/drift.TEMP: Permission denied
chown ntp.ntp /var/lib/ntp/
The solution is shown above and changes the ownership to ntp.ntp which is what the ntpd daemon/server is running as. This is based on Centos but the same idea will apply on any other OS. You can do a "ps aux|grep ntpd" to see what it is running as in the case it's running as a different user.
After that this annoying message wil........
I am running a 64-bit host and was running a 32-bit XPguest which was crawling no matter what I was doing with it,in fact it frequently used 100% CPU power while having no real work load. I experienced with this other guests and wondered why KVM was slow compared to say Xen or Virtualbox.
This is because you need to use the "-cpu" flag.
For a full list of options run:
/usr/libexec/qemu-kvm -cpu ?
x86 ........
This is so handy, especially if you need things like old kernels etc..., this is the main and practically only place you'll ever find what you need.
http://vault.centos.org........
I've encountered this problem before and I believe it may affect other drivers (I could test but I don't have time). This was happening on my custom Linux system with the pcnet32 driver.
pcnet32: eth0: transmit timed out, status 97fb, resetting (and some other kernel module tracing in dmesg)
Basically it means the card is connected (it shows connected in full duplex etc.. and recognized if the cable is disconnected too) but no packets can be sent or received........
*************************************
* *
* All parts have been installed *
*........
One of my test Centos 5 containers was on a partition that filled up and it threw all sorts of errors and stopped responding but now I can't boot it again anymore.
All the console shows is the Linux Penguin on the top left corner and the xm console says "usbcore: registered new driver hub" and has halted there.
Centos 5 Xen container stuck/frozen won't boot on "usbcore: registered new driver hub"
Another great way of troubleshooting is booting fro........
It really is as simple as:
cdrecord -v dev=/dev/sr0 pathtoyourisoimage.iso
-v is for verbose, I prefer it but if you don't you won't see as much output like below (I like to know the details and exactly what's happening)
dev=/dev/sr0 specifies the device name of your burner (they say not to use it and to specify some weird annoying device string but using the raw /dev has always worked for me and is how it should have been implemented from the start IMHO)........
Some minimal installs of Centos may be missing the scp command, which is actually part of the "openssh-clients" package.
scp not found
yum install openssh-clients........
The solution to this screen issue is simple.
This happened to me in Centos 5 as a user, but I also su'd to it and I don't have any password for it.
I've read some people say this is more common when su'ing.
The solution is simple though, just give others rw access to the corresponding pts whether it's 0,1,2 etc..:
As root do
chmod o+rw /dev/pts/2
........
A few days ago this happened on multiple Centos 5 servers and apparently anyone using rpmforge was affected by this error and there was no solution other than disabling that repo to fix it.
To some this highlighted a few points, that there is a reason RHELexists with full paid support, and also that this could be a vulnerability and huge flaw with yum. A yum search or install should not segfault just because the rpmforge repo goes down.
Fortunately it came back up........
ifup eth0
SIOCSIFFLAGS: Cannot allocate memory
Failed to bring up eth0
This is on a Centos 5.5 machine with OpenVZ kernel 2.6.18-238.12.1.el5.028stab091.1PAE, I updated 3 systems with the same hardware to the same kernel and for some reason the network didn't come back.
This only happened once the first time I booted into the new kernel and hasn't happened again but this is a serious issue for those running systems from remote locations such as a datacente........
Warning: Unable to open /dev/fd0 read-write (Read-only file system). /dev/fd0 has been opened read-only.
That's a very annoying error, it's simply because Centos for some reason thinks it's wise to load the "floppy" kernel module, who has a floppy drive? I haven't seen or used a floppy for over 12 years!
It's more than just annoying, if you probe the drives attached to your system, eg. with grub or partprobe, it keeps trying to locate a flopp........
It's weird because I have a nearly identical box and setup and I can update the ovzkernel-PAE* just fine but on this box it doesn't work.
I only get this error with the openvz.repo and not others such as Centos-Base.repo
With my other server it works normally:
================
Setting up Update Process
Resolving Dependencies
--> Running transaction check
---> Package ovzkernel-PAE.i686 0:2.6.18-238.12.1.el5.0........
mod_status is a great way to track down the source of high CPU usage and to find what vhost/script is the cause of it.
It gives you a live view of bandwith usage, CPU usage, and memory usage broken down by domain/vhost and script/URI.
Enable mod_status
vi /etc/httpd/conf/httpd.conf
ExtendedStatus On
SetHandler server-status
Order Deny,Allow
Deny from all
All........
yum -y install vnstat
chown nobody.nobody -R /var/lib/vnstat/
#replace venet0 below with your desired interface
sudo -u nobody vnstat -u -i venet0
#edit: vi /etc/sysconfig/vnstat
#VNSTAT_OPTIONS="-i venet0"
# only use the sed below if you are using venet0 instead of eth0 or replace accordingly
sed -i 's/eth0/venet0/g' /etc/sysconfig/vnstat
[root@monitor]# yum install vn........
Centos 5 Postfix and SPAMASSASSIN Tutorial
yum install spamassassin
chkconfig spamassassin on
vi /etc/mail/spamassassin/local.cf
##############
#required_hits 5
#report_safe 0
#rewrite_header Subject [SPAM]
#5 is the least restrictive (means only the most obvious SPAM is caught. 0 is obviously the most restrictive/sensitive and would have lots of false positives
require........
Jan 16 04:02:03 centosbox syslogd 1.4.1: restart.
Jan 16 04:07:34 centosbox kernel: INFO: task updatedb:20771 blocked for more than 300 seconds.
Jan 16 04:07:34 centosbox kernel: "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
Jan 16 04:07:34 centosbox kernel: updatedb D F78BE050 6476 20771 20766&n........
Webmin Setup Centos 5:
wget http://downloads.sourceforge.net/project/webadmin/webmin/1.530/webmin-1.530-1.noarch.rpm?r=http%3A%2F%2Fwww.webmin.com%2Fstandard.html&ts=1294339690&use_mirror=surfnet
[1] 24229
[2] 24230
[root@host ~]# --2011-01-06 21:48:20-- http://downloads.sourceforge.net/project/webadmin/webmin/1.530/webmin-1.530-1.noarch.rpm?r=http%3A%2F%2Fwww.webmin.com%2Fstandard.html
Resolving downloads.sourceforge.net... 216.34.181.........
This made me nervous but it's clearly a cronjob based on the messages log that happens every Sunday at about 4:22.
I actually can't find any evidence of it in cron.d cron.daily but it is there somewhere obviously.
What I don't get is why doesn't this cronjob do a datacheck like Ubuntu's cronscript does? When you unnecessarily rebuild the array you lose your redundancy during that point which makes your data extremely vulnerable.
*Update I did a grep of &q........
The normal solution doesn't help or apply here:
ssh -v user@192.168.5.41
OpenSSH_4.3p2 Debian-9etch3, OpenSSL 0.9.8c 05 Sep 2006
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Applying options for *
debug1: Connecting to 192.168.5.41 [192.168.5.41] port 22.
debug1: Connection established.
debug1: permanently_set_uid: 0/0
debug1: identity file /root/.ssh/identity type -1
debug1: i........
I've only used it on Centos, soI thought I'd make a quick Debian guide:
Install the DRBD Package
apt-get install drbd8-utils
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages were automatically installed and are no longer required:
libswfdec-0.8-0
Use 'apt-get autoremove' to remove them.
The following........
I wanted to Import/Use a .vmdk hard disk image file from VMWare. Generally you can just "point" VirtualBox to it and use it and it will work but I found an exception.
One of my Centos 4.4 x64 images wouldn't boot. I had two copies, an older one and the newer one. The older one booted as normal (once I changed the VirtualBox driver to IDE from SATA). The newer one stopped at the "GRUB loading" message no matter what I tried.
As far as........
yum exits in the middle
The problem is this VPS seems to be an OpenVZ template from HyperVM. The only way to make it work was to disable i386 packages since this was an x64 kernel. That shouldn't be necessary but it was the only way to make yum stop quitting after the first package or two. I couldn't find any issue by checking the logs either.
echo y|yum install vim-minimal telnet expect jwhois net-tools slocate iptables elinks gawk
L........
Refusing to automatically import keys when running unattended.
Use "-y" to override.
When using echo y|yum install gcc
Fix with rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY*........
Virtually no system has a floppy disk drive anymore but you will often find your Linux distribution insists that you do or should have one :)
The solution is to remove the floppy module and prevent it from loading on the next reboot.
rmmod floppy
Centos/RHEL
echo "blacklist floppy">> /etc/modprobe.d/blacklist
#update initramfs so it takes effect
dracut........
cd /etc/yum.repos.d
wget http://download.openvz.org/openvz.repo
rpm --import http://download.openvz.org/RPM-GPG-Key-OpenVZ
yum install ovz-kernel-PAE
Now remember to set /etc/sysctl.conf to "net.ipv4.ip_forward = 1"
You can apply the change immediately by running sysctl -w net.ipv4.ip_forward = 1 but remember that you still have to set sysctl.conf
sysctl -p will load and apply any changes to s........
This has stumped me a few times because I keep forgetting that Centos 5.5 comes with a default iptables configuration that ends up blocking DRBD traffic,I tried all the normal things and couldn't understand why I couldn't make my normal DRBD config work. So if you have WFConnection problems and have tried the normal "mailing list" fixes, check your firewall status first!
Both Nodes Say the Following:
version: 8.3.8 (api:88/prot........
Virtualbox Error
I tried to copy a .vdi of one container to use in another one, basically to clone instead of having to install the OS again.
Failed to start the virtual machine Centos 5.5 Mirror.
Medium '/home/testuser/.VirtualBox/HardDisks/Centos 5.5 Mirror.vdi' is not accessible. UUID {a1a9fad7-0402-4867-b8f3-39fb49454bc5} of the medium '/home/testuser/.VirtualBox/HardDisks/Centos 5.5 Mirror.vdi' does not match the value {4945a0e8-0ed5-4736-9088-bcaf........
wget http://download.virtualbox.org/virtualbox/3.2.8/VirtualBox-3.2-3.2.8_64453_rhel5-1.i386.rpm
rpm -i http://download.virtualbox.org/virtualbox/3.2.8/VirtualBox-3.2-3.2.8_64453_rhel5-1.i386.rpm
error: Failed dependencies:
libGLU.so.1 is needed by VirtualBox-3.2-3.2.8_64453_rhel5-1.i386
libSDL-1.2.so.0 is needed by VirtualBox-3.2-3.2.8_64453_rhel5-1.i386
libXmu.so.6 is needed b........
NET: Registered protocol family 2
The above is the last thing that I ever saw, I tried pci=routeirq etc.. and it wouldn't work.
The solution is to enable IOAPIC in the VBOX Settings
Just enable "IOAPIC" in the settings for your Centos Guest and you'll find the kernel boots just fine. I wonder if a physical system might stall in this same way if the BIOS has IOAPIC disabled which many people do as a troubleshooting method.
........
Different distributions such as Debian and Centos behave differently when trying to shutdown your system.
shutdown -H now on Debian does not do what you'd expect. The system won't power down, it will halt and do everything but power down.
shutdown -PH now will do the job though (actually power the system off). This is important to test especially if you are not near the system. If you just use -P it forcefully shuts off which is not........
This was done on Centos butI think it's easier on Debian machines, the paths that it is set to use are tailored towards Debian, so there is some fiddling that needs to be done on Centos.
This is for chrooting ssh, but jailkit has other uses than just SSH jails but I won't cover them in this writeup.
1. Install jailkit
yum install jailkit
2. Setup Jail Home
mkdir /home/jail
chown root:root /home/ja........
route add -net 192.16.5.0 netmask 255.255.255.0 eth0
Of course adjust as you need (eg. the 192.16.5.0 should be changed to the subnet you need access to and eth0 should be changed to the network device that you want that subnet routed through). I also use the /etc/sysconfig/rc.local script and add the above into it (remember that this route only gets added AFTER all other init scripts have finished though).........
I wasted a lot of time wondering why I could never find those packages.
Check the /etc/yum.conf file and at the bottom look for the "exclude=" line.
Below is what I found in mine
exclude=apache* httpd* mod_* mysql* MySQL* da_* *ftp* exim* sendmail* php* bind-chroot*
Just remove those entries or uncomment that line and you'll get access to the missing applications.........
Basically the two main types of distros are Debian and RHEL/Centos based. I'm just going to give a quick overview of how the configuration of IP interfaces works in Debian/Centos based distros.
*Just one thing to remember, when setting IPs statically you have to manually specify a DNS server in /etc/resolv.conf (since DHCP is what normally does it automatically)
Debian/Ubuntu/Kubuntu/MEPIS
The IP (DHCP &........
I have an md0 arary that my Centos install refers to. I feel this is half the reason why it won't boot anymore.
I saw the initrd for Centos was assembling it as md127 even though it was known as md0.
The reason for this is because I used mdadm --assemble --scan to detect the array on a LiveCD. I had no idea this name would stick (but now I realize the name is permanently stored in the metadata once you mount md127 or whatever random name assemble gives it). W........
I successfully created a single RAID 1 partition which includes /boot inside it and my root directory through the Debian installer. It said GRUB installed successfully but when I try booting the OS it seems GRUB can't read anything.
When trying to boot from GRUB
GRUB Loading stage 1.5.
GRUB loading, please wait...
Error 2
I get "Error 2" when trying to boot Debian. I also notice from a LiveCD that........
I installed 5.5 with a 300GB RAID 1 partition (boot is also on this partition). It booted up fine the first few times until after I used a Live CD and accessed the array, and it became named /dev/md127 for some reason.
Now whenI boot into CentOS I get a kernel panic and different errors, once I got "invalid superblock", even though the array is fine (it didn't happen again, probably because I was sure to dismount and stop the mdadm array properly).
Here's what........
This function and others may not work with the stock PHPinstall on Centos/CPanel: Fatal error: Call to > undefined function imagecreatefromjpeg()
Even with libjpeg-devel installed it won't work because PHP was not compiled with jpeg support, so we have to do the dirty work ourselves :)
Here is the command/yum's I did to install missing libraries for PHP that configure will complain about (yes it is a one by one process).
yum install bzip2-........
This was unbelievable how much the Xen kernel slows things down, keep in mind both tests were done on the hostnode, one was with the Openvz-Xen hybrid kernel and the other was just OpenVZ. You can see the performance difference is nearly 300% better when not using the Xen kernel.
OpenVZ-Xen Kernel Test Results (I was wondering what was wrong/so slow with my Core i5!)
# # # # # #&n........
This is a very simple solution, but most guides out there make you login twice (once to scp the key) and once to put the key in authorized_keys. There's no need for that.
If you don't already have a ~/.ssh/id_rsa.pub just type "ssh-keygen -t rsa" and keep hitting enter until it's done :)
Just use this code to easily enable passwordless login with SSHD
key=`cat ~/.ssh/id_rsa.pub`;ssh user@192.168.5.25 "echo $key >> ~/.ssh/auth........
I decided on using yum to help me decide even though I normaly use proftpd I decided to see what else I could find.
yum search ftp
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
* rpmforge: ftp-stud.fht-esslingen.de
* base: mirrors.netdna.com
* updates: updates.interworx.info
* addons: yum.singlehop.com
* extras: mirrors.netdna.com
rpmforge........
Proxmox has made this free utility to backup running OpenVZ containers. It's a great program which is actually just a PERL script but gets the job done. This program is not 100% required because all it really does is cp -a from your container's path as far as I know but it is still good to have uniformity to how you backup your containers.
For RPM distros such as Centos/RHEL/Fedora etc.. download and install this:
wget http://www.proxmox.com/cms_proxm........
CentOS (most Linux) no-RAID to software RAID-1 guidehttp://lists.centos.org/pipermail/centos/2006-January/018624.html........
Centos 4.3 x64 & VMWare Server Beta[code:1:6d0b2c8c2f]
The correct version of one or more libraries needed to run VMware Server may be
missing. This is the output of ldd /usr/bin/vmware:
linux-gate.so.1 => (0xffffe000)
libm.so.6 => /lib/tls/libm.so.6 (0xf7fbd000)
libdl.so.2 => /lib/libdl.so.2 (0xf7fb9000)
libpthread.so.0 => /lib/tls/libpthread.so.0 (0xf7fa7000)
libX11.so.6 => not f........
Upgrade Release Kernel TipsThis is for CentOS 3.1 to 3.8 but the methodology will apply everywhere.
I ran into a problem first of all with a non-booting system after running
#yum update centos-release
It took me to 3.8 and upgraded all the other packages [b:7e931c835d]BUT[/b:7e931c835d]
because of some stupid flags enabled in /etc/yum.conf the KERNEL WASN'T UPGRADED SO AFTER BOOTING, WELL IT DIDN'T BOOT OF COURSE :)
H........
Setup Static IP Address ONBOOTAssuming you are using eth0
Note this will work for any version of CentOS and basically any version of Redhat Linux or Redhat based distribution.
You would need to create a new file
[code:1:02f8d34c30] /etc/sysconfig/network-scripts/ifcfg-eth0:0[/code:1:02f8d34c30]
DEVICE=eth0:0
the ":0" at the end specifies alias 0 we could actually change this to ":99" or "........
Need identd for port 113 ? Install authdyum install authd
Happy identing :)Actually it's not that simple.
It installs as an "xinetd" service and is disabled and turned off by deafult.
To enable it run:
[code:1:8c94df8319]
chkconfig --level 3 auth on
service xinetd restart
[/code:1:8c94df8319]
This will set identd aka authd to start by default.
service xinetd resta........
/usr/bin/ld: cannot open crt1.o: No such file or directory[quote:812bec9db7]/usr/bin/ld: cannot open crt1.o: No such file or directory
collect2: ld returned 1 exit status[/quote:812bec9db7]
This is annoying and in my case it happened on Centos AMD 64 when compiling a 32bit program with GCC.
Install glibc-devel.i386 (make sure you get the i386 version and not the native 64 bit version which is likely already installed).
The joys of 3........
Updating yum repos for DAG /etc/yum.repos.dIn /etc/yum.repos.d
[quote:96456b2ab9]Create any file such as "CentOS-Dag.repo" in /etc/yum.repos.d[/quote:96456b2ab9]
Add the following to the above file:
[code:1:96456b2ab9]
[dag]
name=Dag RPM Repository For Red Hat Enterprise Linux
baseurl=http://dag.atrpms.net/redhat/el$releasever/en/$basearch/dag/
http://dag.freshrpms.net/redhat/e........
Shortcut/Easiest Way To Create A Self-Signed Key:
openssl req -new -x509 -nodes -days 1530 -out server.crt -keyout server.key
Using the above, you instantly create a self-signed certificate valid for 1530 days and you can simply skip to step #5.) below.
If You Need a Real SSLCertificate (eg. Equifax/Openssl) then you need to create a CSR request (you'll need to follow Steps 1.) and 2.) in order to create the CSR. You then upload the CSR Certi........
It's a bit of a pain that many basic third party tools that aren't put of the main Centos/RHEL repositories are not available unless you compile them or install the RPMForge Repo.
*Updated 08/29 with new download location changed from apt.sw.be to rpmforge.sw.be
Here's a quick, simple/cut&paste way to do it:
wget http://rpmforge.sw.be/redhat/el5/en/i386/rpmforge/RPMS/rpmforge-release-0.5.1-1.el5.rf.i386.rpm
rpm -i rpmforge........
Inever saved any of the logs, but basically no matter what OS (Linux)I used, I could not get my 1000GB hard drive to work (Seagate SATA). The BIOS recognizes the drive and fdisk -l shows the hard drive as it should.
The tricky thing is that different OS's will give you different results, but don't be fooled. You can't use these larger drives for long. Iwas getting all kinds of seek/IOerrors and also messages that the port could not be read.........
In Newer Linux Distros This Way Is Easiest and works on newer versions like Ubuntu, Mint, Fedora, Centos, Debian etc.
#if you are missing timedatectl this in newer distros like Ubuntu/Mint/Debian and are using a container like Docker then do "apt install systemd"
timedatectl set-timezone America/Vancouver
Replace the America/Vancouver with the correct timezone.
To see the list you can just type "timedatectl set........
For some reason Ikeep getting this error when trying to run a sudo command eg:
sudo -u someuser somecommand
sudo: Error dropping capabilities, aborting
My version of sudo is:sudo-1.6.9p17-3.el5_3.1 and I've heard that version 1.7 fixes everything. The only thing is yum does not think sudo has any update. Iguess the new version has not been committed to the RPM repository yet.
This is really a huge and ann........
This is something that annoys a lot of people, fortunately the Redhat style OS's are the most simple in this respect. I disagree that Debian's way makes sense, it is more of a hackish approach in how they implement iptables.
Anyway, for those who are using Redhat/Centos style OS's it is very simple.
Set your rules from the shell/command prompt and to save the iptables firewall rules so they are remember/loaded on boot just run this command:
service iptables........
Server not using user level security and no password supplied.
tree connect failed: NT_STATUS_WRONG_PASSWORD
That happens when trying to use smbclient to connect to a share. The weird thing is that I can authnenticate just fine from Windows XP.
It is partially my mistake, I forgot this share does have a password. I've tried authenticating with the correct user and also with "Guest" because this works in Windows. In Linux I ........
There's a lot of information and guides on OCFS2 for RHELand Centos Linux but the package setup and configuration is slightly different and this has thrown some people off.
Installing OC2FS
You should install the following packages to get started:
apt-get install ocfs2-tools ocfs2console
Configure OC2FS
In RHEL/Centos the main configuration file is located in /etc/sysconfig/o2cb
However in Debian based Linux it is located........
There's a lot of outdated information and confusion for system administrator's out there.
One annoying task for many an Administrator has been backing up data in Linux. You don't need any GUI tools such as K3B or GnomeBaker. Both are excellent tools but for veteran command line users working remotely, using the keyboard is a great and possibly automated way to save yourself pain and hassle.
At a later date we'll cover how scripting can automatically backup certain........