Are Restarts Necessary?

Q&A
1

I’m a long-time Linux user, but new to a rolling updates model and have a question.

I run Clear Linux on 2 computers that run 24/7. I have a “normal” desktop install of Clear, I’m not trying to run them headless or anything special.

Those boxes run BOINC 24/7 to do crunching for World Community Grid. I have let them set to autoupdate, and hence my question:

Both computers are receiving updates regularly; do I ever need to restart them, so that any low-level changes can be implemented?

Thanks for your time.

2

Yes. Restarts are required to update things that are loaded in memory and can’t be swapped out easily, like the running kernel.

Clear Linux will automatically restart certain whitelisted services after an update to make sure the newest software is in use but can’t do this for all services without making too many assumption about a system and potentially interrupting service. It tries to notify users that an update requiring a restart is pending.

You can also add your own services to this whitelist: https://docs.01.org/clearlinux/latest/guides/maintenance/restart.html

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3

Yes, it’s necessary to reboot to update the kernel, for example. Some services are automatically restarted on update, but others are left alone because of the potential impact (gdm, X, etc.).

You can check the MOTD for hints, though:

$ cat /var/run/motd
 * A kernel update is available: you may wish to reboot the system.
 * Some system services need a restart.
   Run `sudo clr-service-restart -a -n` to view them.
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4

Thanks for the information.

5

Thanks! This is a big help, with this I can just regularly check the MOTD and only restart if needed.

6

Detail:

  • you can’t restart the kernel without rebooting (effectively)
  • you can’t restart dbus without making pretty much everything else restart

These 2 items are the essence of why reboots are still needed. The rest we can handle much more gracefully.

1 Like
7

Thanks, I assumed as much, but just wanted to confirm.