I guess what I was most worried about was how Pacemaker would respond to one of the nodes being restarted (assuming one of the updates required a restart). But if I place the cluster into maintenance-mode beforehand it shouldn't be flagged as UNCLEAN or anything right?
On Mon, Jan 21, 2013 at 8:40 AM, Florian Crouzat <[email protected]>wrote: > 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 > _______________________________________________ Linux-HA mailing list [email protected] http://lists.linux-ha.org/mailman/listinfo/linux-ha See also: http://linux-ha.org/ReportingProblems
