How to kill a docker swarm

Assign way more replicas than you have of memory on all nodes and watch the Swarm crash which can easily reproduce in a small VMfor testing. root@Deb11Docker01:~# docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAM........

nvidia cannot resume from sleep Comm: nvidia-sleep.sh Tainted: Linux Ubuntu Mint Debian

This seems to happen in many different drivers but it happened more often in newer versions such as 530 vs 525. Then nvidia-modeset goes to 100% There are many reports of this appearing since driver 4.70 and I can confirm I've seen this in various machines. https://forums.de........

How to access a disk with bad superblock Linux Ubuntu Debian Redhat CentOS ext3 ext4

Have you ever tried mounting a partition that you exists but you get this error? mount: /mnt: can't read superblock on /dev/sda1. The superblock in this example was bad because the physical disk had corruption and bad blocks/sectors. However, the data was generally accessible and you can always try this trick below (with caution and no warranty). This is specifically for filesystems that place superblocks in multiple locations, which........

How To Upgrade Debian 8,9,10 to Debian 12 Bookworm

Step 1.) Upgrade to Debian 11 first The process to go to Debian 12 is not as smooth as 11, when trying to upgrade from Debian 10. In fact, it doesn't work directly, so you'll first need to follow this guide to update to Debian 11, reboot and come back here if successful. Step 2.) Update sources.list Update your /etc/apt/sources.list like this: deb http://........

apache2 httpd apache server will not start [pid 22449:tid 139972160445760] AH00052: child pid 23248 exit signal Aborted (6) solution Mint Debian Ubuntu Redhat

If you get this error, it is often because you have configured Apache with modules that weren't actually installed. Eg. you try to load the PHPmodule but didn't actually install the apache2 php module, so the server can't start. In general, this error can often be caused by issues with problematic modules and/or Apache being configured for modules that have not actually be installed (eg. libapache2-mod-php) is missing. The above results in this less than obv........

How To Setup Python3 in Ubuntu Docker Image for AI Deep Learning

The issue is that Docker images are stripped down, so many tools and even python3 is missing, so you'll have to build or update the actual image yourself. I assume you have started an image with something like this and that you have the Nvidia Toolkit installed (assuming you are using GPUs). If you're not using nvidia just remove --runtime=nvidia --gpus all. docker run -it --runtime=nvidia --gpus all ubuntu bash These works for most images li........

How to upgrade to the latest Python version on Linux Ubuntu Debian Mint 3.11

A lot of developers want to go to 3.11 because of the speed improvements, but most distros never have the latest Python version. Using the deadsnakes third party repo is the easiest way aside from compiling it yourself (which is safer and recommended): Step 1 - Add the repo apt-add-repository ppa:deadsnakes/ppa If you get an error about requests then install it:........

debootstrap how to install Ubuntu, Mint, Debian install

In this example we install debian 10 with --variant=minbase which gives us a minimal/tiny install. Don't use variant if you want the full size install. mkdir /tmp/deb10files debootstrap --variant=minbase buster /tmp/deb10files/ Did you get an error? debootstrap --variant=minbase buster /home/theuser/VMs/deb10files/ You'll get this error if you make a directory in your home........

ModuleNotFoundError: No module named 'pip._internal' solution python

pip3 install requests Traceback (most recent call last): File "/home/user/.local/bin/pip3", line 7, in from pip._internal.cli.main import main ModuleNotFoundError: No module named 'pip._internal' As a quick and temp fix call the OS installed python and not the user .local/bin installed pip3 /usr/bin/pip3 install requests Collecting requests Cache e........

Cisco Switch / Router How To Restore Factory Default Settings

1.) Make sure your conf register is 0x2102 Do show version and at the very end of the output you will see the Configuration register. show version Configuration register is 0x2102 If the config register is not 0x2102 then enter this command: r1#configure terminal r1(config)#config-register 0x2102 r1(config)#end 2.) Let's Erase the NVRAM/flash........

Cisco 2900 3900 Router Password Reset How To Reset Enable Password

It is a bit different and annoying here for these types of routers/models as you need to physically remove the CF (Compact Flash) and only then, will it enter ROMMON mode (Ctrl + Pause remotely over the console will not do it for us). This means you cannot do this remotely, or at least not without the help of a remote/physical helper. Step 1.) Power off, router and remove CF Disk Slot#2 Go to the router and remove the slot#2 cover uses your hand or it may help to use a........

i915 nouveau Nvidia GPU not starting lightdm Xorg failing solution for Could not determine valid watermarks for inherited state

It may appear to be an Xorg or lightdm/gdm/mdm error but in reality for many users with this issue, it's a driver conflict and issue. I had a system that had two GPUs, an Intel and Nvidia GPU. The only thing that got it working was to remove the nouveau driver and blacklist it so it never came back, then the Intel GPU works fine without these issues. Solution sudo rmmod nouveau add nouveau/other driver to blacklist edit th........

GlusterFS HowTo Tutorial For Distributed Storage in Docker, Kubernetes, LXC, KVM, Proxmox

This can be used on almost anything, since Gluster is a userspace tool, based on FUSE. This means that all Gluster appears as to any application is just a directory. Applications don't need specific support for Gluster, so long as you can tell the application to use a certain directory for storage. One application can be for redundant and scaled storage, including for within Docker and Kubernetes, LXC, Proxmox, OpenStack, etc or just your image/web/video files or even da........

Vbox Virtualbox DNS NAT Network Mode NOT working

There is a random bug that sometimes occurs with Vbox NAT mode DNS, although it has never happened in the past and Vbox was working fine until recently. The symptom is that you can see it does get an IP+ DNS from the Vbox NAT DHCP. Below we use resolvectl dns and verify the DNS server is set to 10.0.2.3 which is the DNS from Vbox NAT. We can ping it but it does not respond to any DNS requests when we use dig @10.0.2.3 realtechtalk.com........

Docker Tutorial HowTo Install Docker, Use and Create Docker Container Images Clustering Swarm Mode Monitoring Service Hosting Provider

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.........

How To Create OpenVPN Server for Secure Remote Corporate Access in Linux Debian/Mint/Ubuntu with client public key authentication

Why choose OpenVPN instead of a firewall appliance? OpenVPN can be a reliable and easy replacement for traditional hardware or just be an additional tool that your company uses so that the firewall can focus on its job rather than acting as a VPNappliance at the same time. When comparing OpenVPN with traditional firewal........

How to install Kubernetes with microk8s and deploy apps on Debian/Mint/Ubuntu Linux

Kubernetes Easy Beginners Tutorial/Architecture Guide Kubernetes is known as container orchestration and we should start at explaining the container part of it. A Container is what runs the actual application and based on an Image, and are more comparable to something like an LXC Container, Virtuozzo/OpenVZ using the Linux Kernel Namespaces feature. Containers run these images as independent, isolated operating environments under the O........

apcupsd how to setup and monitor APC UPS units

It really seems limited in that it can mainly give you the things you would see on the physical unit such as load etc.. wget https://downloads.sourceforge.net/project/apcupsd/apcupsd%20-%20Stable/3.14.14/apcupsd-3.14.14.tar.gz?r=https%3A%2F%2Fsourceforge.net%2Fprojects%2Fapcupsd%2Ffiles%2Flatest%2Fdownload&ts=1598115866 tar -zxvf apcupsd-3.14.14.tar.gz cd apcupsd-3.14.14 [root@somebox apcupsd-3.14.14]# ./conf........

How To Get Started on Ubuntu with gpt-2 OpenAI Text Prediction

apt install software-properties-common add-apt-repository ppa:deadsnakes/ppa apt update apt install python3-pip apt install python3.7 curl gnupg python3.7-dev git ln -s /usr/bin/python3.7 /usr/bin/python3 pip3 install numpy keras_preprocessing curl https://bazel.build/bazel-release.pub.gpg | sudo apt-key add - echo "deb [arch=amd64] http://storage.googleapis.com/bazel-apt stable jdk1.8" | sudo tee /etc/apt/sources.list.d/bazel........

Linux How To Change NIC Name to eth0 instead of enps33 or enp0s25

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........

How To Install python 3.4 3.5 and up on Linux with wine - Working Solution

This is sure simple if you follow the guide but it took a lot of hacking around to make this work on Debian/Ubuntu! Now before you ask why bother running wine and python, the reason is because Python executables are NOT cross-platform. If you run pyinstaller in Linux, that binary will only run on Linux and the same if you do it in Windows. So it is preferable if you have a single environment that you can create Linux and Windows binaries from rather than running 2 separate........

Radeon R3 GPU on Debian Crashing

Occasionally my whole screen locks up and I cannot even swith to the console and I find this in my syslog: *-display description: VGA compatible controller product: Mullins [Radeon R3 Graphics] vendor: Advanced Micro Devices, Inc. [AMD/ATI] ........

Convert and install to LUKS Encrypted Drive Ubuntu 18.04 19.10 Linux Mint and Debian Based Linux

The reason for doing this is that the installer doesn't seem to work properly for LUKS and the server installer doesn't even support LUKS anymore. When you use the GUI install on Desktop for LUKS it won't boot and will just hang after you enter your password. So the only reliable way is to do it ourselves. 1.) Make a default minimal install of Ubuntu 2.) Have a secondary disk on the server or VM. 3.)........

CentOS 6 and 7 / RHEL Persistent DHCP Solution

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........

python import docx error

sudo pip3 install python-docx [sudo] password for : Downloading/unpacking python-docx Downloading python-docx-0.8.10.tar.gz (5.5MB): 5.5MB downloaded Running setup.py (path:/tmp/pip_build_root/python-docx/setup.py) egg_info for package python-docx no previously-included directories found matching 'docs/.build' warning: no previously-included files matching '.DS_Store' foun........

RTNETLINK answers: Network is unreachable

This often happens if you are adding a secondary route, especially with Linux source based routing. ip route add default via 10.10.10.254 table 10 RTNETLINK answers: Network is unreachable If that happens you will probably find that it is unreachable because your NIC does not have an IP in the 10.10.10.0/24 range so just assign an IP in that range to your NIC and try again. eg. ifconfig eth0 10.10.10.254 netmask 255.255.255.0 up........

Cisco Unified Communications Manager 12 Install Errors on Proxmox/KVM

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-kvm command: /usr/libexec/qemu-kvm -version QEMU PC emulator version 0.12.1 (qemu-kvm-0.12.1.2-2.506.el6_10.1), Copyright (c) 2003-2008 Fabrice Bellard ........

Linux delete unused tap devices automatically

This will find all tap devices and try deleting all of them. Of course don't run this if there is a chance an unused tap device is necessary and would not be created by the script ro application using it. for tap in `ifconfig -a|grep tap[0-255]|awk '{print $1}'`; do tunctl -d $tap done........

Centos 6 or 7 no DHCP IP during startup on first boot or reboot solution

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.........

Debian / Mint / Ubuntu net-tools packages provides netstat, ifconfig, route, arp and other classic network admin tools

The net-tools command brings back all of the oldschool tools that we're used to: /bin/netstat /sbin/ifconfig /sbin/ipmaddr /sbin/iptunnel /sbin/mii-tool /sbin/nameif /sbin/plipconfig /sbin/rarp........

Cisco Switch Reset To Factory Defaults

This works on the 2000 and 3000 series generally. *The easy way is to just hold the mode button for 10+ seconds. The full/proper way is below: 1.) Either power on the unit and hold the "mode" button or hold the "mode" button until you see the below: 00:04:08: %SYS-7-NV_BLOCK_INIT: Initalized the geometry of nvram 00:04:08: %EXPRESS_SETUP-6-CONFIG_IS_RESET: The configur........

Proxmox Breaks Storage/LVM Backing If Killing QEMU-IMG

I tried to stop a qemu-img copy or clone and it broke everything. It was fine to "stop" it from the GUI but a process still persisted so I killed the relevant qemu-img and the kernel went crazy. It also may not have helped that I tried to lvremove a different volume (an unused disk). But either way it breaks LVM (you cannot even run lvdisplay) so a reboot is necessary. Jan 17 06:45:21 testserver kernel: [ 5680.439337] systemd-udevd D 0&nbs........

bind named error solutions named[2169]: error (no valid DS) resolving / error (broken trust chain) resolving / : error (no valid RRSIG) resolving 'com/DS/IN':

Below are the common errors you'll get with named AKA bind if your time is incorrect. The simplest solution is to install and run ntpd to correct your system's time (install ntpd if it is not installed) systemctl start ntpd systemctl enable ntpd Dec 20 13:36:16 hostingbox named[2169]: error (no valid DS) resolving 'develop.waxrain.com/A/IN': 14.215.150.17#53........

gvfs mount in /run/user cannot be accessed or displayed wrong permissions Error: Location is already mounted

You get errors like below and see you have all question marks for the permissions if you go to /run/user/1000/gvfs If you try to access the mounted share such as anything mounted as gvfs like an SSH share in your file manager you may get an error like this. It generally means an interruption in communication or a fault with gvfsd has caused it. Solutio........

VMWare ESXi 6.7 SSH/PowerShell CLI Commands

[root@localhost:~] BootModuleConfig.sh echo host-ind nfcd........

OpenVPN cannot ping remote IP routing loop issue after connecting

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........

Linux Mint USB Kernel Tainted and Locked Port/Dev File

Essentially a program I was running for mining did not terminate properly with Ctrl+C it is listed as defunct and cannot be killed, kernel is tainted and normal tricks to disable the port are impossible the dev and sys entries for the device cannot be browsed or interacted with in any form without a lockup of the request. The only solution is to reboot due to the kernel taint as far as I can find so far. [1130246.811056] INFO: task minerd:21861 blocked for more th........

ffmpeg Linux Mint download, compile and install howto

#if you have nvidia make sure you install the nvidia-cuda-toolkit so hardware acceleration can be used wget http://ffmpeg.org/releases/ffmpeg-3.3.2.tar.bz2 tar -jxvf ffmpeg-3.3.2.tar.bz2 cd ffmpeg-3.3.2/ ./configure --disable-yasm install prefix /usr/local source path ........

USB 3.0 External HDD Enclosure Seagate UAS problems - [sdd] tag#1 CDB: Write(16) 8a 00 00 00 00 01 70 04 08 68 00 00 00 08 00 00

This is a 8TB Seagate external USB 3.0 device apparently newer kernels use a module called "UAS" instead of "USB Storage" which causes issues as a lot of devices are not properly supported in UAS mode by the kernel driver. The solution some say is to disable UAS specifically for your USB device but I'd rather just disable UAS altogether. Solution blacklist UAS: *do not do this it does not work and just causes your USB 3.0........

cudaminer freezes Linux Mint taints kernel

When running cudaminer once it tries to initialize the card the entire screen freezes. The computer itself is still running but the Xorg is done for, you cannot even switch to another console window and must reboot (even an mdm or Xorg restart does not help). At first cudaminer will give you these errors: stratrum_recv_line failed ...retry after 15 seconds GPU #0: Geforce 210 with compute ca........

phpBB3 slow and internal dummy connection

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 Migration Guide from Centos 6

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........

mdadm frozen and doesn't realize array is dead/missing failed due to unplugged drives

This was a surprising bug but I unplugged all drives for an array md127. At first it was just 1 drive and mdadm seemed to notice this. I unplugged the second drive taking the array offline but mdadm did not realize it was offline and still showed a non-existent disk as being part of it. This created problems trying to unmount it or even to stop this array with mdadm freezing. As for how to fix it I can only think of making sure you are not in a mounted path of........

DRBD Split-brain solution

Uh oh [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 [1682]) [17925926.174432] block drbd0: data-integrity-alg: [17925926.174581] block drbd0: drbd_sync_handshake: [17925926.174586] block drbd0: self 2AAE66AF9252D6DB:2815BF........

OpenVZ Solution CPT ERR: c02fa000,73 :CPT: lock fd is closed incorrectly: 1 and vps-net_add ERROR: Unable to add route ip route add 192.168.5.2 dev venet0

The only solution after trying many suggestions was to simply restart the "vz" service (definitely not preferable). Even doing an ifdown and ifup for venet0 did not help. ifup venet0 Bringing up interface venet0: Configuring interface venet0: net.ipv4.conf.venet0.send_redirects = 0 RTNETLINK answers: Network is down Some errors from log: CPT ERR: d2dc60........

blocked for more than 120 seconds issues with iowait and timeout on Live Linux distribution while writing to physical disk

This happened while an mdadm array was syncing, all access from writing a new blank file to opening a small .txt file was very slow: [222117.312078] kjournald starting. Commit interval 5 seconds [222117.685060] EXT3-fs (md0): using internal journal [222117.685096] EXT3-fs (md0): mounted filesystem with ordered data mode [222122.376847] kjournald starting. Commit interval 5 seconds [222122.602825] EXT3-fs (md2): using internal jour........

Centos Add Multiple IP Addresses in a range without manually setting each static IP

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........

KVM/QEMU how to boot from direct kernel vmlinuz and initrd with networking

Thsi is very handy when doing your own kernel development. -m specifies how much ram (in the example it is 768MB) -kernel specifies the path to the kernel file -net tap,ifname=tap1,script=no (the ifname=tap1 is what you need to change and setup manually). *Run "tunctl -b" to create a tap device and use the one it gives you for ifname= Enable networking to the outside like this: *Note we assume that your bridge is br0 i........

Centos automatic ifcfg-eth0 scripts based on list of IPs from bash

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........

drbd howto solve splitbrain or WFConnection

On primary node drbdadm connect all On secondary node drbdadm -- --discard-my-data connect all ........

Centos Howto Upgrade to PHP 5.3 from 5.2

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........

CPanel suhosin install failed

/scripts/phpextensionmgr install PHPSuHosin Updating md5sum list Fetching http://httpupdate.cpanel.net/cpanelsync/easy/targz.yaml (connected:0).......(request attempt 1/12)...Resolving httpupdate.cpanel.net...(resolve attempt 1/65)... Fetching http://httpupdate.cpanel.net/mirror_addr_list (connected:0).......(request attempt 1/3)......connecting to 74.50.120.123...@74.50.120.123......connected......receiving...100%......request success......Done........

Dell FS12-NV7 2U Server Information and Guide

I've got one of these for testing projects from work at home and got more than I bargained for with the time I've spent on it due to the storage handing/Perc 6/i cards. My particular model came with the following: 2U Rack Mount Server with Rails 2xOpteron 2373 EE (Quad Core, there is a 6-core version that can be found at times) 16GB RAM 2 x 250GB Seagate SATA 2 x Dell Perc 6/i (horrible and a nightmare to work........

LSI MegaRAID Adventures, Guide and HowTo

LSi Megaraid At first it was configured as a RAID 0, then I deleted the Virtual Disk Group. I thought both drives would be shown and detected in Linux as sda and sdb but it actually shows nothing. To make them work you have to hit Ctrl+R before the system boots (when prompted) and create a Virtual Disk Group. In my case I created each one as RAID 0 (with a single drive only) as I just wanted JBOD but there is no such option or default in these Dell Pe........

WD 20EARX Dead Again

Another new drive bad from the start: Jun 2 15:14:18 one-desktop kernel: [15895.386779] ata2.00: exception Emask 0x50 SAct 0x1 SErr 0x280900 action 0x6 frozen Jun 2 15:14:18 one-desktop kernel: [15895.386782] ata2.00: irq_stat 0x08000000, interface fatal error Jun 2 15:14:18 one-desktop kernel: [15895.386784] ata2: SError: { UnrecovData HostInt 10B8B BadCRC } Jun 2 15:14:18 one-desktop kernel: [15895.386788] ata2.00: cmd 60/0........

eth0 changed to eth1 or eth2 and the solution to fix it

If you move your hard drive(s) around to other computers/servers, you'll find that your eth0 keeps getting higher, the first time it will become eth1 and then eth2 etc and even higher if your server has dual or quad NICs. The reason is that udevd basically assigns eth0 tot he first NIC it finds and remembers it, if it encounters a NIC with a differentMAC, it assigns it one higher (eg. eth1). See the example below, I have eth2 now so how doI fix it?........

Kernel panic - not syncing: Attempted to kill init! Pid: 1,comm: init Tained: G I------------- 2.6.32-358.el6.x86_64 #1 Call Trace: [] ? panic+0xa0/0x16f [] ? do_exit+0x862/0x870 [] ? fput+0x25/0

Kernel panic - not syncing: Attempted to kill init! Pid: 1,comm: init Tained: G I------------- 2.6.32-358.el6.x86_64 #1 Call Trace: [] ? panic+0xa0/0x16f [] ? do_exit+0x862/0x870 [] ? fput+0x25/0x30 [] ? do_group_exit+0x58/0xd0 [] ? sys_exit_........

Bad Hard Drive Slows Down Computer

Here's a proven example of what a bad hard drive can do, it was technically functioning OKin a RAID array but the system became extremely low and the load become high and IOWAIT was even higher and I always thought it was a bad application. The truth is that this failing 1TBHitachi has slowly gotten worse and caused huge slowdowns, (eg. 100% load on Thunderbird waiting for e-mails to load etc..). After swapping it out, tabs change instantly, emails are not lagged, and........

Linux Kernel Panic Messages - Symptoms of bad RAM module/stick

These were caused by a bad stick of Corsair RAM [] free_hot_cold_page+0xfc/0x150 [] __pagevec_free+0x14/0x1a [] release_pages+0x127/0x12f [] __pagevec_release+0x15/0x1d [] __invalid_mapping_pages+0x120/0x156 [........

Linux Out of Memory OOM Object Killer Solution "Out of memory: kill process 1955 (sshd) score 81 or a child"

I had a system running a 128MB live CD image with 2.8 gigs of available RAM and the OOM kernel killer went crazy when using dd for more than 8 minutes and kept killing everything. I've read that this is due to a low-memory issue and paging in the kernel and 32-bit systems with lots of RAM. I even enabled swapspace on my LiveCD and the issue happened 25 minutes into dd rather than 8 minutes, so what gives? Also no swap space was ever used! cat /proc/s........

How To Test If Your Hard Drive Is Good/Signs of dying hard drive

I like dd, although it only reads it, usually a read test of the entire disk will uncover if your hard drive is bad in some parts. This is a good thing to do at least once a month, a lot of times bizarre program behavior, laginess and crashing/unnmounting problems etc.. are due to a failing disc and SMART won't know it or indicate a problem: We must also remember there's never a guarantee, I've found that ever since we moved to larger and more platters per drive with 1TB drives........

email server messsages rejected without reverse DNS DNS check failure Client host rejected: cannot find your reverse hostname Cannot resolve PTR record

Basically you should always be 100% sure that whatever IPyour mail server sends out with has reverse DNS/PTR records. Remember that unless you own your IPs then you won't be able to set your own reverse DNS. Even if you were to create a reverse PTR record on your DNS servers it will be ignored. Reverse DNS is queried to pre-assigned DNS servers of your ISP, so therefore you'll need to contact your ISP/Colo/Hosting provider to do a reverse DNS entry. If you don't have........

CPU #1 not responding - cannot use it.

I think this will be useful to others because I have a server that kept crashing mysteriously during intense disk usage/RAID checks. It would only crash during the weekly RAID integrity check. ThenI noticed during a reboot that not all CPUs were being brought up, as a result this actually creates much higher temperatures with the output I got from sensors, just booting the system produced higher than normal temperatures. You can imagine that a full blown RAID check........

updatedb/mdadm caused a kernel panic?

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........

Ubuntu/Debian DRBD 8.0 Setup Guide

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........

vzquota : (warning) Incorrect quota shutdown for id 2333, recalculating disk usage vzquota : (error) quota check : lstat `sess_a5078fce5f569e453ab1fb39b0fc69f8': No such file or directory vzquota on failed [1]

first container would not come up: Starting CT 2333: service vz stop OpenVZ is locked [FAILED] 2010-11-29T23:26:23-0800 vzctl : CT 2333 : Starting container ... 2010-11-29T23:37:21-08........

mdadm RAID 1 adventures

I separated the 2 drives in the RAID 1 array. 1 is the old one /dev/sda and is out of date, while the separated other one /dev/sdc was in another drive and mounted and used with more data (updated). I wonder how mdadm will handle this: usb-storage: device scan complete md: md127 stopped. md: bind md: md127: raid array is not clean -- starting background reconstruction raid1: raid set md127 active with 1 out of 2 m........

Directadmin License Error 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/ifco

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 Solution /usr/local/directadmin/scripts/getLicense.sh........

DRBD WFConnection Problem/Solution

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........

After installation Directadmin does not work directadmin dead but pid file exists on OpenVZ VPS when browsing http://ip.ip.ip.ip:2222

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 tail /var/log/directadmin/error.log 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........

Realtek r8169 1gbit/1000mbit NIC/Ethernet Goes Down/Halts on Large File Transfer/Heavy Network Usage

This is obviously a bug in the r8169 kernel module and it seems to affect a lot of people. I upgraded to the latest kernel and hope this won't happen anymore, as it is a very serious error. This is especially serious for those who are running servers with this chipset, who can afford for the NIC to randomly go off-line for no apparent reason? [655548.189113] type=1505 audit(1277067560.902:5): operation="profile_load" name="/usr/bin/freshclam&q........

How To Set DHCP/Static IP Address in Centos/RHEL/Fedora & Debian/Ubuntu/Kubuntu/MEPIS Set DHCP/Static IP Address

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 &........

Why does mdadm have two sets of UUID's?

Which one does the OS care about? blkid says the UUID is "787f1fa4-b010-4d77-a010-795b42884f56" while md insists its UUID is "4d96dd3b:deb5d555:7adb93cb:ce9182d9" When in doubt, do we assume the OS takes the one from blkid? /dev/md0: UUID="787f1fa4-b010-4d77-a010-795b42884f56" TYPE="ext3" [root@localhost ~]# mdadm -D /dev/md0 /dev/md0: Version : 0.90 &........

PHP cannot access /usr/bin/openssl

PHP cannot access /usr/bin/opensslI have verified the username that runs the process is able to access /usr/bin/openssl and it does exist but the PHP script is saying it doesn't exist: [code:1:1fd0f3abbe] if (!file_exists($OPENSSL)) { //echo "ERROR: OPENSSL $OPENSSL not foundn"; }[/code:1:1fd0f3abbe] I don't get itI can clearly see the contents of /usr/bin by using the PHP system fu........

JavaScript get valued of selected <select> drop down l

JavaScript get valued of selected drop down l [code:1:4be190f44a]Package = OrderForm.package.options[OrderForm.package.selectedIndex].value;[/code:1:4be190f44a] OrderForm = Name of HTML form the SELECT is inside package = Name of SELECT element eg. JavaScript says form name is not defined even though it is I've integrated this into my design and I got an error saying the Form Name i........

Setup Static IP Address ONBOOT

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 "........

Updated to Version 3.8 and can't login

Updated to Version 3.8 and can't loginSSHD accepts my password but then hangs at "Last login: Wed Sep 13 21:30:02 2006 from" This occurred during a yum update after upgrading my release, installing the new kernel and rebooting. I got kicked out of sshd after seeing the following during yum update: telnet 100 % done 85/476 tux 100 % done 86/476 ntsysv 100 % done 87/476 rpmdb-redhat 94 % done 88/476........

Need identd for port 113 ? Install authd

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........

OCFS2 crash

When trying to even cd or ls the mounted OCFS2 partition it crashes. Ithink this is a combination of VMWare Server's problem and the way I mounted and symlinked to it. More than anything this shows the problem and lack of forsight with VMWare, but also that OCFS2 is easily crashed if you do strange things. Output of /var/log/messages for OCFS2 Apr 10 15:57:45 localhost kernel: [84331.691258] Modules linked in: vmnet vmci vmmon ocfs2_stac........