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Posts in Linux
Sending alerts to your Linux desktop when things go wrong
I run gnome on my work desktop, and even with our various monitoring solutions I still use some custom notification tools to get alerted when specific issues occur. One of these tools is gnome-notify, which allows you to create a visible notification inside your desktop workspace. This tool has several useful options, which are displayed when you run notify-send with the "-?" option: To use this tool to send an alert when a fault is detected, I typically wrap some conditional logic to parse the output of one or more commands: The code above will run the command embedded inside $(), and capture the output from this command in the variable system_check. If the value of the output is 1, then notify-send will be invoked to send a notification with the string "Problem with server X" to my desktop…
$ read more →Sending commands to multiple Linux and Solaris machines through a single graphical shell window
I have been a long time user of clusterssh, which is a fanstastic tool for sending commands to multiple hosts. Inside each terminal window you can type a command, or you can use the master console to send a command to all of the windows you opened. The clusterit tools comes with a similar tool, dvt, which is quite similar to clusterssh. Dvt uses the CLUSTER variable just like dsh and company, and has a master console that allows you to send commands to each server in that list…
$ read more →Managing 100s of Linux and Solaris machines with clusterit
I use numerous tools to perform my SysAdmin duties. One of my favorite tools it clusterit, which is a suite of programs that allows you to run commands across one or more machines in parallel. To begin using the awesomeness that is clusterit, you will first need to download and install the software. This is as easy as: Once the software is installed, you should have a set of binaries and manual pages in /usr/local/clusterit…
$ read more →How to ensure sure you can boot if your initrd image has problems
I was playing around with some new kernel bits a few weeks back, and needed to update my initrd image. Having encountered various situations where a box wouldn't boot due to a botched initrd file, I have become overly protective of this file. Now each time I have to perform an update, I will first create a backup of the file: Once I have a working backup, I like to add a menu.lst entry that allows me to restore to a know working state: If my changes cause the machine to fail to boot, I can pick the backup menu entry and I'm off and running. If you don't want to pollute your menu.lst, you can also specify the initrd manually from the grub command menu…
$ read more →Why the ext3 fsck's after X days or Y mounts?
Reading through my RSS feeds, I cameacross the following blog post describing one Linux administrator using tune2fs to disable the "please run fsck on this file system after X days or Y mounts." I've got to admit, this is kind of annoying. I've taken production critical Linux boxes down for some maintenance, only to have the downtime extended +15-30 minutes because the file system was configured to run a fsck. Google searching this topic even shows other administrators trying other stupid tactics to avoid the fsck on reboot. Is there really any value on having fsck run after some period of time…
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