We're hosting multiple Websites with different Content Management Systems, also with different Versions. There are multiple Debian servers running on one esxi. I want to introduce a Windows-like Patch day every month, where we upgrade the packages on the servers. I'm curious how other admins plan such patch days. I've planed it so far:
- aptitude update && aptitude upgrade --simulate -V to see which packages needs to be upgraded and if there are any major upgrades.
- Make a snapshot of the Server
- Upgrade the packages
- Check server logs and take some Website samples
If all was successful, deleting the snaptshot 3 days after. If there a any errors, restore the snapshot and take a deeper look at the problem. I know this concept is quite sketchy. How's your patch routine? I'm worried that the upgrade may break some dependencies. But the are to many Websites to manually check every for their specific dependencies. I think of some kind of semi-automatic unit test, to check that the dependencies are still intact after every patch day. Did anybody has a buzz word, to start my search from?
We are using Icinga to monitor all servers, including monitoring for CPU Load, HDD space etc. Also we have a good running backup system.
Thanks in advance