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.........
It really seems limited in that it can mainly give you the things you would see on the physical unit such as load etc..
tar -zxvf apcupsd-3.14.14.tar.gz
It is fairly simple to use once you know how to use it. However, the tricky thing is that by default it doesn't seem to be active or listen on any interface on manually specified.
How To Install ifplugd
First we install ifplugd
sudo apt install ifplugd
Let's enable it on our desired device(s)
set this line as so:........
A lot of times busy servers will have this issue and you cannot even force kill -9 the apachectl or httpd process:
[root@apachebox stats]# ps aux|grep httpd
root 1547 0.0 0.2 495452 32396 ? Ds Sep08 3:23 /usr/sbin/httpd
root 3543 0.0 0.0 6448 724 pts/1 S+ 13:11&nbs........
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........
Just edit your tftp file for xinetd like this:
*Change the IPto be the IPof the interface you want to listen on.
To test if your tftp is available on a certain IP range use nc -u yourip 69 to see if you can still connect (/var/log/messages or /var/log/syslog) should show the connection if it is open.
Oct 13 23:20:34 01 xinetd: Started working: 1 available servic........
service sshd status
● ssh.service - OpenBSD Secure Shell server
Loaded: loaded (/lib/systemd/system/ssh.service; enabled; vendor preset: enabled)
Active: failed (Result: start-limit-hit) since Wed 2019-10-02 11:07:54 EDT; 36s ago
Process: 476 ExecStartPre=/usr/sbin/sshd -t (code=exited, status=255)
Oct 02 11:07:54 box systemd: Failed to start OpenBSD Secure Shell server.
Oct 02 11:07:54 box sys........
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........
If you get error messages like this it is usually because /var/run/sshd does not exist.
root@userbox:/# service sshd status
● ssh.service - OpenBSD Secure Shell server
Loaded: loaded (/lib/systemd/system/ssh.service; enabled; vendor preset: enab
Active: failed (Result: start-limit-hit) since Wed 2019-04-10 02:24:44 EDT; 1
Process: 511 ExecStartPre=/usr/sbin/sshd -t (code=exited, status=255)........
The strange thing is that usually the first install or two will work on any new machine but then it suddenly won't. I had this experience on QEMU 2.13 on a different machine. There is something finicky or buggy about the CUCM installer even when choosing the same virtual hardware specs.
QEMU PC emulator version 0.12.1 (qemu-kvm-0.12.1.2-2.506.el6_10.1), Copyright (c) 2003-2008 Fabrice Bellard
The net-tools command brings back all of the oldschool tools that we're used to:
In a RAID array I had a have periodically lost a drive here and there over the past several months. Iwas always able to readd and resync without losing data. However at some point it looks like some minor corruption happened and this makes DRBD unhappy.
Using fsck did not help either.
Dec 19 06:01:45 storageboxtest4 kernel: [19005.945890] EXT3-fs error (device drbd0): ext3_get_inode_loc: unable to read inode block - inode=22184379........
Before getting into the output here is my typical experience with SMART, there is what I call a "bad disk" with pending and uncorrectable sectors that cannot be reallocated.
It has caused a kernel panic and system crash repeatedly as we can see from the logs.
But SMART says it has "PASSED" its self assessment. SMART is still useful to me but it is more about looking at Current_Pending_Sector.
Any time I have had anything but 0 for that attribute it........
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:
list-units [PATTERN...] List loaded units
nfs mount failed:
mount 10.10.2.20:/tmp/nfsmount /mnt/nfs/
mount: wrong fs type, bad option, bad superblock on 10.10.2.20:/tmp/nfsmount,
missing codepage or helper program, or other error
(for several filesystems (e.g. nfs, cifs) you might
need a /sbin/mount. helper program)
Sometimes if you have a very basic configuration OpenVPN on the client side for some reason sends all traffic to the OpenVPN server IP through the tun0 which is of course impossible and creates a block or routing loop.
This is because you need to use your normal ISP/LANgateway to hit the OpenVPN server if it is remote/offsite as is usually the case. So if you are connected to the OpenVPN through say a tun0 device and your routing is set to connect to the OpenVPN&nbs........
This is not the normal "black screen"issue and I was shocked to eventually find out why. The normal advice of reconfiguring Xorg didn't work. Even booting into "Recovery Mode" did not help.
Here is the short end of the stick that fixed it:
sudo apt-get install mdm mate-desktop-environment
Yes you got it right, mdm and the mate-desktop-environment / gnome were somehow uninstalled. This must be whe........
It is well known hackers, the NSA, CIA and other groups have created malware to secretly turn on your webcam and microphone on your phone, tv etc.. But fortunately on our computers and laptops we have some options.
Most webcams use the "uvcvideo" kernel module / driver. You can disable this in two ways on boot. I recommend both just as a failsafe.
Disable it on rc.local once your system boots automatically
Add the followi........
[Wed Sep 20 15:34:44 2017] [notice] suEXEC mechanism enabled (wrapper: /usr/sbin/suexec)
[Wed Sep 20 15:34:44 2017] [error] Init: Unable to read server certificate from file /www/ssl-certs/server.crt
[Wed Sep 20 15:34:44 2017] [error] SSL Library Error: 218529960 error:0D0680A8:asn1 encoding routines:ASN1_CHECK_TLEN:wrong tag
[Wed Sep 20 15:34:44 2017] [error] SSL Library Error: 218595386 error:0D07803A:asn1 encoding routines:ASN1_ITEM_EX_D2I:nested asn1 error........
[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........
[17925926.174277] block drbd0: Handshake successful: Agreed network protocol version 96
[17925926.174325] block drbd0: conn( WFConnection -> WFReportParams )
[17925926.174342] block drbd0: Starting asender thread (from drbd0_receiver )
[17925926.174432] block drbd0: data-integrity-alg:
[17925926.174581] block drbd0: drbd_sync_handshake:
[17925926.174586] block drbd0: self 2AAE66AF9252D6DB:2815BF........
It all comes down to a bug essentially where you are running an older kernel that doesn't support the newer Debian templates. The solution is to update your OpenVZ kernel.
Here are some symptoms of the problem/lack of kernel support:
Ubuntu Template 12.04 requires a manual network start:
service networking start
sshd will not start:
PRNG is not seeded
mknod /dev/random c 1 8........
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:
You have dual NICs and you disable NIC1 which uses 192.168.1.1 as its gateway. With NIC2 you enable it/connect it to another network which also has the gateway 192.168.1.1
Everything will work fine at this point.
When switching back to NIC1 even with NIC2 disabled and even unplugged, the OS basically can't pick up the new/updated ARP entry of the old device for 192.168.1.1 and perhaps thinks it is a security risk or spoof of some sorts and blocks i........
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,
#count=10000 makes an image of 10000MB make sure your image is at least the same as your existing
dd if=/dev/zero of=yourimage.img bs=1M count=10000
# losetup -fv newimage.raw
# fdisk -cu /dev/loop0
# kpartx -a /dev/loop0
# dd if= of=/dev/mapper/loop0p1
# e2fsck -f /dev/mapper/loop0p1
# resize2fs /dev/mapper/loop0p1
# a lot of guides tell you to edit /etc/fst........
./configure: cannot locate gcc 3.x. please install it or specify with --qemu-cc
yum -y install gcc make
./configure: cannot locate gcc 3.x. please install it or specify with --qemu-cc
yum -y install compat-gcc-*
Error: Could not find alsa
Make sure to have the alsa libs and headers installed.
yum -y install alsa-lib-devel
mount -o bind /proc /sda2/proc
mount -o bind /dev/ /sda2/dev
mount -o bind /sys /sda2/sys
mint / # mount -o bind /proc /sda2/proc
mint / # mount -o bind /dev/ /sda2/dev
mint / # mount -o bind /sys /sda2/sys
mint / # chroot /sda2
mint / # cd ~
mint ~ # ls
mint ~ # cd /
mint / # ls
bin Desktop dev-temp home&nb........
Step #1 - Create Wrapper Script
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........
* All parts have been installed *
I experienced this with CPanel's Exim after an auto-update (a Google of this error produces lots of complaints with few clear solutions). In this case I'll put the solution at the top.
Run /scripts/buildeximconf to rebuild the Exim config and it should be fine after that.
mail -vs "from test" firstname.lastname@example.org < .bash_history
cwd=/root 4 args: send-mail -i -v email@example.com
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
# 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........
You need to enable the httpd daemon with monit to actually view the status and control, it's not only for the web interface since the httpd is theONLY way of controlling monit and viewing the status.
monit monitor all will also reinstate disabled services if they've timed out too much. Just restarting the service will do nothing to re-monitor a service that monit has stopped monitoring due to too many failures.
*Also note that /etc/monit.conf i........
Centos 5 Postfix and SPAMASSASSIN Tutorial
yum install spamassassin
chkconfig spamassassin on
#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
I found the cause of this issue was from all the diskspace being used but clearing it was not enough. Iguess the tables became inconsistent when space ran out and myisamchk is what fixed the rest.
service mysqld restart
ERROR! MySQL manager or server PID file could not be found!
....................................................................................... ERROR! Manager of pid-file quit without updating file.
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:
Use 'apt-get autoremove' to remove them.
2010:09:09-22:22:11: The ip of this machine (xx.xx.xx.xx) does not match the ip in the license file.
Check the value of your ethernet_dev=venet0:0 setting in your /usr/local/directadmin/conf/directadmin.conf file and the output of /sbin/ifconfig
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
chown root:root /home/ja........
After installation Directadmin does not work on OpenVZ VPS when browsing http://ip.ip.ip.ip:2222
service directadmin status
directadmin dead but pid file exists
Check the value of your ethernet_dev=eth0 setting in your /usr/local/directadmin/conf/directadmin.conf file and the output of /sbin/ifconfig
2010:07:10-12:44:01: ioctl can't find........
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:
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:
chkconfig --level 3 auth on
service xinetd restart
This will set identd aka authd to start by default.
service xinetd resta........
User nobody in passdb, but getpwnam() fails!
I never found the solution to this in the web, as usual so Ithought I'd post the fix. In plain English smbd is telling us that the user "nobody" does not exist in /etc/passwd.
You can simply add this to your /etc/passwd file like so:
Now SAMBA/smbd should........