Auto-update server idea. What do you think?

[oshunluvr]

I am patiently waiting for 14.04 to release and stabilize (June?) and I will then likely upgrade my server. I've decided to add a new level of automation to it by having it automatically update itself at regular intervals along with the ability to rollback if an update fails. Since I use btrfs, snapshot-ing is easy and takes little space.

Here's the gist of my idea:

Daily (weekly?) cronjob will snapshot, then update and dist-upgrade.
A kernel count will be maintained and auto-remove all but the current and two previous kernels.
Snapshots will be limited to the two most recent also.

All the above is rather easy. I'm wondering if I should have the system reboot itself whenever a new kernel is installed or if it should just email a notification requesting a reboot. I'm leaning toward the latter so I don't leave myself without a server when I'm away.

Topics for discussion are:

What are the possible pitfalls?
How often is often enough or too often to update and reboot?
Can or should recovery be automated also? In other words, does a failed boot result in auto-reboot to previous state?
Should some packages be excluded from auto-update? For example: a failed grub will leave the system unbootable and unrecoverable without manual intervention, so should grub be excluded (grub package update, not update-grub)?

I'm interested to hear what I'm missing...

[sithlord48]

after you install a new kernel you should get a restart notice, not a forced restart. . i do remember a while back there was a module you could install that would upgrade to the new kernel and not require a reboot (using kexec maybe?). i used to have it on my server many installs ago.

[oshunluvr]

Yeah, I realize the restart isn't forced - just required to use the new kernel. I was suggesting I program it to auto-reboot so that the new kernel would be used without my intervention.

Really, there are several functions that I rely on my server for so maybe the whole thing isn't a good idea. I suppose if I do a once weekly auto-update and snapshot, I would only have to check on it once a week. Probably once the release is more than a year old I could do an update monthly and still be up-to-date enough.

[SteveRiley]

i do remember a while back there was a module you could install that would upgrade to the new kernel and not require a reboot (using kexec maybe?).

Or maybe KSplice? A wonderful bit of open source software until Oracle bought and subsequently ruined it. Now, they develop it primarily for Oracle Linux. Graciously, they still provide some free versions -- KSplice Uptrack for Ubuntu and Fedora, basically just us desktop freetards. A manual installation version expands this somewhat.