Yum update

the_gripmaster · 05-29-2012, 12:26 AM

I have a bunch of CentOS 5.5 servers which are in production use. I would like to know what actually happens underneath when I update them.

Running an yum update (pointing to the default repos) will update to CentOS 5.8. Now, during the update process, say apache httpd v 2.2.2 is running live serving pages while at the same time I run yum update and it updates the apache httpd to v 2.2.3. Seems like a very obvious question, but does the it restart the httpd service?

Also, updating from CentOS 5.5 to 5.8 would it matter if I not reboot the machine. A reboot will pick the latest installed kernel but other than that is it ok to keep the server running without a reboot?

cliffordw · 05-29-2012, 12:37 AM

I personally would be very hesitant to update & not reboot asap in a production environment, as I have had unexplained problems after upgrading & not rebooting in the past. Any chance you can test this in a DEV environment first?

the_gripmaster · 05-29-2012, 12:50 AM

Quote:

Originally Posted by cliffordw

I personally would be very hesitant to update & not reboot asap in a production environment, as I have had unexplained problems after upgrading & not rebooting in the past. Any chance you can test this in a DEV environment first?

Not really. I did update the dev environments but had rebooted soon after the yum update.

Yes, now I realize there could be issues not rebooting after such a major leap in versions.

blue_print · 05-29-2012, 07:26 AM

If Yum upgrades httpd, it will definitely restarts httpd since it erases existing version and installs the new one. This scenario, you do not require reboot.

If you upgrade the system packages like kernel etc, you must need to reboot the system.

the_gripmaster · 06-19-2012, 11:33 PM

Quote:

Originally Posted by blue_print

If Yum upgrades httpd, it will definitely restarts httpd since it erases existing version and installs the new one.
[...truncated...]

Found some new info on this: http://it.toolbox.com/blogs/locutus/...ebooting-12826

So after apache (httpd) is updated, the older version is still in memory and it is the one running. A restart of the service will load the updated binaries/libraries.

deep27ak · 06-20-2012, 04:16 AM

Quote:

Originally Posted by blue_print

If you upgrade the system packages like kernel etc, you must need to reboot the system.

I don't believe its mandatory to reboot the system after kernel upgrade, but if you install a new kernel then you need to reboot your machine from the new kernel.

iashkan · 06-20-2012, 04:51 AM

personally I will reboot asap if it is's a desktop computer
but for server I'll wait to have several acceptable reasons for that.

the_gripmaster · 06-20-2012, 07:44 PM

Quote:

Originally Posted by deep27ak

I don't believe its mandatory to reboot the system after kernel upgrade, but if you install a new kernel then you need to reboot your machine from the new kernel.

Correct. Yum always "installs" (rather than update) a new kernel. So it is okay not to reboot unless you want to run using the latest installed kernel.