Le 21/01/2013 02:30, Josh Bowling a écrit : > Hi all, > > I have an Ubuntu 12.04 based HA cluster running a few CentOS VMs and was > wondering what the best practices are for updating both the host machines > and virtual machines that are managed by Corosync + Pacemaker? > > I was thinking that I would put the cluster into maintenance-mode and then > update the machines, but what if one of the updates require a machine > reboot? I'm just worried that something will cause my cluster, and > therefore my services, to go down. > > Here are the steps I was thinking: > 1. put cluster into maintenance-mode > 2. update vms > 3. update secondary host > 4. switch secondary host to primary (moving vms) > 5. update host that was primary
This way of performing updates is called "rolling upgrade". See http://clusterlabs.org/wiki/Upgrade for other possibilities. > > How does that sound? I'm not sure how switch secondary to primary by > command, but I'm sure it's in the documentation somewhere. And I guess > when I switch secondary to primary all of the VMs will be down > momentarily? What do the professionals do to keep all of their cluster > machines up to date without angering the entire customer base? If you intend to also update your VMs, I guess you will have to reboot them on the new kernel, so yes, you have to bring them down anyway, you can take this chance to reboot them on the correct node, eg: 1. maintenance-mode 2. move all VMs to a single node, say node2 3. update node1, reboot, rejoin cluster 4. For each VM on node2: 4.1. Update VM 4.3. Shutdown VM (from outside the cluster) 4.2. Boot VM on already-up-to-date node1. (from outside the cluster) (and I'm assuming shared storage of course) 5. once node2 is free of VMs, update node2, reboot, rejoin cluster 6. all VMs are up-to-date on node1, both nodes are up-to-date 7. reprobe/cleanup resources 8. disable maintenance-mode. That's only if you /need/ to reboot the VMs, otherwise, there may be live migration stuff, I don't use linux-ha with virtualization... My 2 cents ;) -- Cheers, Florian Crouzat _______________________________________________ Linux-HA mailing list [email protected] http://lists.linux-ha.org/mailman/listinfo/linux-ha See also: http://linux-ha.org/ReportingProblems
