On 2015-02-05 17:08, Andrea wrote:
Hi
I test location constraint with ping resource to stop resource on
disconnected node, but with stonith active, doesn't works
I used dummy resource for test
[ONE]pcs resource create mydummy ocf:pacemaker:Dummy op monitor
interval=120s --clone
Ping resource
[ONE] pcs resource create ping ocf:pacemaker:ping dampen=5s
multiplier=1000
host_list=pingnode --clone
Location Constraint
[ONE]pcs constraint location mydummy rule score=-INFINITY pingd lt 1 or
not_defined pingd
If the pingnode became not visible on node2, I will see pingd attribute
on
node2 set to 0 and dummy resources stop on node2.
If I cut off nentire network on node2, I will see pingd attribute on
node2
set to 0 bud dummy resource never stop.
During network failure...stonith agent is active and try to fence node
1
without success.
Why? Is the failed fence action that block location constraint?
Andrea
When you disable stonith, pacemaker just assumes that "no contact" ==
"peer dead", so recovery happens. This is a very false sense of security
though, because most people test by actually crashing a node, so there
is no risk of a split-brain. The problem is, in the real world, this can
not be assured. A node can be running just fine, but the connection
fails. If you disable stonith, you get a split-brain.
So when you enable stonith, and you really must, then pacemaker will
never make an assumption about the state of the peer. So when the peer
stops responding, pacemaker blocks and calls a fence. It will then sit
there and wait for the fence to succeed. If the fence *doesn't* succeed,
it ends up staying blocked. This is the proper behaviour!
Now, if you enable stonith *and* it is configured properly, then you
will see that recovery proceeds as expected *after* the fence action
completes successfully. So, setup stonith! :)
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