[ClusterLabs] Resource-stickiness is not working

[Ken Gaillot]

On Sat, 2018-06-02 at 22:14 +0800, Confidential Company wrote:
> On Fri, 2018-06-01 at 22:58 +0800, Confidential Company wrote:
> > Hi,
> > 
> > I have two-node active/passive setup. My goal is to failover a
> > resource once a Node goes down with minimal downtime as possible.
> > Based on my testing, when Node1 goes down it failover to Node2. If
> > Node1 goes up after link reconnection (reconnect physical cable),
> > resource failback to Node1 even though I configured resource-
> > stickiness. Is there something wrong with configuration below?
> > 
> > #service firewalld stop
> > #vi /etc/hosts --> 192.168.10.121 (Node1) / 192.168.10.122 (Node2)
> --
> > ----------- Private Network (Direct connect)
> > #systemctl start pcsd.service
> > #systemctl enable pcsd.service
> > #passwd hacluster --> define pw
> > #pcs cluster auth Node1 Node2
> > #pcs setup --name Cluster Node1 Node2
> > #pcs cluster start -all
> > #pcs property set stonith-enabled=false
> > #pcs resource create ClusterIP ocf:heartbeat:IPaddr2
> > ip=192.168.10.123 cidr_netmask=32 op monitor interval=30s
> > #pcs resource defaults resource-stickiness=100
> > 
> > Regards,
> > imnotarobot
> 
> Your configuration is correct, but keep in mind scores of all kinds
> will be added together to determine where the final placement is.
> 
> In this case, I'd check that you don't have any constraints with a
> higher score preferring the other node. For example, if you
> previously 
> did a "move" or "ban" from the command line, that adds a constraint
> that has to be removed manually if you no longer want it.
> -- 
> Ken Gaillot <kgaillot at redhat.com>
> 
> 
> >>>>>>>>>>
> I'm confused. constraint from what I think means there's a preferred
> node. But if I want my resources not to have a preferred node is that
> possible?
> 
> Regards,
> imnotarobot

Yes, that's one type of constraint -- but you may not have realized you
added one if you ran something like "pcs resource move", which is a way
of saying there's a preferred node.

There are a variety of other constraints. For example, as you add more
resources, you might say that resource A can't run on the same node as
resource B, and if that constraint's score is higher than the
stickiness, A might move if B starts on its node.

To see your existing constraints using pcs, run "pcs constraint show".
If there are any you don't want, you can remove them with various pcs
commands.
-- 
Ken Gaillot <kgaillot at redhat.com>