Archive
Posts from 2012
How to encrypt an SSH private key
If you are using SSH key-based authentication you should be encrypting your private key. This ensures that if someone breaks into your server and steals your keys, they won't be able to utilize them to access other systems. If your private key isn't encrypted you can use the ssh-keygen utilities "-p" option to do so: This option can be used to change the password used to encrypt a private key, and to add a password to an existing private key. Viva la OpenSSH!
$ read more →Book review Pulling Strings With Puppet
The devops movement (if you haven't seen Ben Rockwood's presentation on devops you should go watch it now) has been gaining steam over the past few years, and the movement has led to a lot of organizations adopting automation solutions like CFEngine, Chef or Puppet. I've had great success with puppet so far, and my fellow blogging partner Mike has had similar success with CFEngine. Maybe Mike will come out of hibernation and give everyone an update on the cool things he's done with it. :) When I first started using Puppet I purchased a copy of James Turnbull's Pulling Strings with Puppet…
$ read more →Using the automated bug-reporting tool (abrt) to generate core dumps when a Linux process fails
Software fails, and it often occurs at the wrong time. When failures occur I want to understand why, and will usually start putting together the events that lead up to the issue. Some application issues can be root caused by reviewing logs, but catastrophic crashes will often require the admin to sit down with gdb and review a core file if it exists. Solaris has always led the charge when it comes to reliably creating core files during crashes…
$ read more →Bind's strict zone checking feature is part of CentOS 6
I recently moved a bind installation from CentOS 5 to CentOS 6. As part of the move I built out a new server with CentOS 6, staged the bind chroot packages and then proceeded to copy all of the zone files from the CentOS 5 server to the CentOS 6 server. Once all the pieces were in place I attempted to start up bind. This failed, and I was greeted with the following error: There wasn't anything in /var/log/messages to specifically state what the problem was, though when I reviewed the bind log file I noticed there were several "not loaded due to errors" messages in it: After reviewing the errors I noticed that the problematic zone files (I was not the original author of these) were configured to use forward references to entries in subzone files…
$ read more →Locating Linux LVM (Logical Volume Manager) free space
The Linux Logical Volume Manager (LVM) provides a relatively easy way to combine block devices into a pool of storage that you can allocate storage out of. In LVM terminology, there are three main concepts: Physical Volumes A sequence of sectors on a physical device. Volume Groups A group of physical volumes. Logical Volumes A logical device that is allocated from a volume group…
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