[Pacemaker] Slave does not get become Master after unplugging power cable at master

hj lee kerdosa at gmail.com
Wed Aug 19 00:39:21 UTC 2009


Thank very much for the reply.

I tested it both stonith-enabled and no-quorum-policy. As Dejan pointed,
this is related to stonith-enabled. With stonith-enabled true (which is
default),
if I kill the master node, the slave stays as a slave, it seems expecting
something from stonith. With stonith-enabled false, the slave was promoted
to master.

The no-quorum-policy controls the behavior when the quorum is not enough.
With no-quorum-policy stop, when one of two nodes dies, the resources in the
other node get stopped. With no-quorum-poolicy ignore, when one of two nodes
dies, nothing happens. If master die, the slave stays as a slave. If slave
dies, the master stays as a master.

By the way during the test, no-quorum-policy works only in openais stack.
With heartbeat stack, there is no difference between no-quorum-policy stop
and ignore. It seems the heartbeat stack always behavior as no-quorum-policy
ignore.

Here are my new questions:
How does stonith detect the node was actually down? Doesn't it get this info
from the cluster stack? Does it have its own mechanism like pinging the
other nodes? Can stonith:external/ipmi detect the node is down? Which type
of stonith has this ability?

Always thank you very much
hj

On Mon, Aug 17, 2009 at 4:58 PM, Dejan Muhamedagic <dejanmm at fastmail.fm>wrote:

> Hi,
>
> >
> > I defined stonith:ssh, they are running in both machines as a clone. How
> is
>
> How do you expect ssh to work if you pull the power plug from the
> target node?
>
> > the stonith related to promoting standby? When the Pacemaker detects
> master
> > node was gone in cluster, then why doesn't Pacemaker promote the standby?
>
> In case of such an event, when a node disappears without saying
> goodbye, the other node has to make sure that the node which left
> is down and not only unreachable, that's where fencing comes in.
>
> >
> > On Mon, Aug 17, 2009 at 4:00 PM, Dejan Muhamedagic <dejanmm at fastmail.fm
> >wrote:
> >
> > >
> > > >
> > > > I am very simple Master/Slave in RHEL 5.3 with pacemaker 1.0.4 and
> > > heartbea
> > > > 2.99. I unplugged the power cable at the master machine, and I
> expected
> > > the
> > > > slave becomes master. But the slave stays at slave state. Is this
> correct
> > > > behavior or a bug? How does Pacemaker (or heartbeat) handle this kind
> of
> > > > sudden power off?
> > >
> > > You probably didn't define fencing (stonith).
> > >
> > > Thanks,
> > >
> > > Dejan
>
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