Updating CentOS (RHEL, Fedora)

This is just a very concise summary to guide you through the typical update process of a CentOS based Linux server that has no control panel installed on top of it. This post will also appear in our virtual server hosting BLOG:

  1. run yum check-update from the shell.
    This will give you a list of newly available packages for your distribution based on the repositories you have defined. This list will typically not be too long for a well maintained server, unless the distribution itself has just undergone a major update (such as from CentOS 5.7 to 5.8 recently).
  2. check the packages listed and ensure that your currently running applications will still be compatible with the new versions of any packages updated.
  3. make backups of any individual settings you have made for any packages that are going to be updated (httpd.conf, php.ini, etc.). Usually, these will not be touched, but it doesn’t hurt to make sure you have a copy (in addition to the regular backups you should be doing!).
  4. once you have confirmed that everything should still be fine after the update, from the shell, run yum update.
    This will start the update process, and you will actually have to confirm the update before it is really being processed (last chance to say “no”!).
  5. once complete, restart affected services (such as httpd, for example), or reboot your server if vital system packages have been updated (kernel, libc, …)