Recently we’ve upgraded one of our virtualization clusters (more RAM), and in the course of this did an upgrade of the virtualization hosts from Ubuntu Lucid to RHEL 6.3 — without any service interruption. Read more
For people using the VIM editor I’ve got two small tips when editing Pacemaker configurations:
As briefly mentioned in Pacemaker Explained, DRBD devices need two different values set for their monitor intervals:
primitive pacemaker-resource-name ocf:linbit:drbd \ params drbd_resource="drbd-resource" \ op monitor interval="61s" role="Slave" \ op monitor interval="59s" role="Master"
The reason is that Pacemaker distinguishes monitor operations by their resource and their interval – but not by their role. So, if this distinction is not done “manually”, Pacemaker will monitor only one of the two (and, with DRBD 9, more) nodes, which is not what you want (usually).
We’ve recently come across a case where stopping pacemaker (in this case via
/etc/init.d/heartbeat stop) didn’t work; and, similarly,
crm configure property maintenance-mode=false wouldn’t work.
The bug seems to have been a locking problem.