[ClusterLabs] [Question:pacemaker_remote] About limitation of the placement of the resource to remote node.

[Andrew Beekhof]

> On 13 Aug 2015, at 10:23 am, renayama19661014 at ybb.ne.jp wrote:
> 
> Hi All,
> 
> We confirmed movement of pacemaker_remote.(version:pacemaker-ad1f397a8228a63949f86c96597da5cecc3ed977)
> 
> It is the following cluster constitution.
>  * sl7-01(KVM host)
>  * snmp1(Guest on the sl7-01 host)
>  * snmp2(Guest on the sl7-01 host)
> 
> We prepared for the next CLI file to confirm the resource placement to remote node.
> 
> ------------------------------
> property no-quorum-policy="ignore" \
>   stonith-enabled="false" \
>   startup-fencing="false"
> 
> rsc_defaults resource-stickiness="INFINITY" \
>   migration-threshold="1"
> 
> primitive remote-vm2 ocf:pacemaker:remote \
>   params server="snmp1" \
>   op monitor interval=3 timeout=15
> 
> primitive remote-vm3 ocf:pacemaker:remote \
>   params server="snmp2" \
>   op monitor interval=3 timeout=15
> 
> primitive dummy-remote-A Dummy \
>   op start interval=0s timeout=60s \
>   op monitor interval=30s timeout=60s \
>   op stop interval=0s timeout=60s
> 
> primitive dummy-remote-B Dummy \
>   op start interval=0s timeout=60s \
>   op monitor interval=30s timeout=60s \
>   op stop interval=0s timeout=60s
> 
> location loc1 dummy-remote-A \
>   rule 200: #uname eq remote-vm3 \
>   rule 100: #uname eq remote-vm2 \
>   rule -inf: #uname eq sl7-01
> location loc2 dummy-remote-B \
>   rule 200: #uname eq remote-vm3 \
>   rule 100: #uname eq remote-vm2 \
>   rule -inf: #uname eq sl7-01
> ------------------------------
> 
> Case 1) The resource is placed as follows when I spend the CLI file which we prepared for.
>  However, the placement of the dummy-remote resource does not meet a condition.
>  dummy-remote-A starts in remote-vm2.
> 
> [root at sl7-01 ~]# crm_mon -1 -Af
> Last updated: Thu Aug 13 08:49:09 2015          Last change: Thu Aug 13 08:41:14 2015 by root via cibadmin on sl7-01
> Stack: corosync
> Current DC: sl7-01 (version 1.1.13-ad1f397) - partition WITHOUT quorum
> 3 nodes and 4 resources configured
> 
> Online: [ sl7-01 ]
> RemoteOnline: [ remote-vm2 remote-vm3 ]
> 
>  dummy-remote-A (ocf::heartbeat:Dummy): Started remote-vm2
>  dummy-remote-B (ocf::heartbeat:Dummy): Started remote-vm3
>  remote-vm2     (ocf::pacemaker:remote):        Started sl7-01
>  remote-vm3     (ocf::pacemaker:remote):        Started sl7-01

It is possible that there was a time when only remote-vm2 was available (so we put dummy-remote-A there) and then before we could start dummy-remote-B there too, remote-vm3 showed up but due to resource-stickiness=“INFINITY”, we didn’t move dummy-remote-A.

> 
> (snip)
> 
> Case 2) When we change CLI file of it and spend it,

You lost me here :-)
Can you rephrase please?

> the resource is placed as follows.
>  The resource is placed definitely.
>  dummy-remote-A starts in remote-vm3.
>  dummy-remote-B starts in remote-vm3.
> 
> 
> (snip)
> location loc1 dummy-remote-A \
>   rule 200: #uname eq remote-vm3 \
>   rule 100: #uname eq remote-vm2 \
>   rule -inf: #uname ne remote-vm2 and #uname ne remote-vm3 \
>   rule -inf: #uname eq sl7-01
> location loc2 dummy-remote-B \
>   rule 200: #uname eq remote-vm3 \
>   rule 100: #uname eq remote-vm2 \
>   rule -inf: #uname ne remote-vm2 and #uname ne remote-vm3 \
>   rule -inf: #uname eq sl7-01
> (snip)
> 
> 
> [root at sl7-01 ~]# crm_mon -1 -Af
> Last updated: Thu Aug 13 08:55:28 2015          Last change: Thu Aug 13 08:55:22 2015 by root via cibadmin on sl7-01
> Stack: corosync
> Current DC: sl7-01 (version 1.1.13-ad1f397) - partition WITHOUT quorum
> 3 nodes and 4 resources configured
> 
> Online: [ sl7-01 ]
> RemoteOnline: [ remote-vm2 remote-vm3 ]
> 
>  dummy-remote-A (ocf::heartbeat:Dummy): Started remote-vm3
>  dummy-remote-B (ocf::heartbeat:Dummy): Started remote-vm3
>  remote-vm2     (ocf::pacemaker:remote):        Started sl7-01
>  remote-vm3     (ocf::pacemaker:remote):        Started sl7-01
> 
> (snip)
> 
> As for the placement of the resource being wrong with the first CLI file, the placement limitation of the remote node is like remote resource not being evaluated until it is done start.
> 
> The placement becomes right with the CLI file which I revised, but the description of this limitation is very troublesome when I compose a cluster of more nodes.
> 
> Does remote node not need processing delaying placement limitation until it is done start?

Potentially.  I’d need a crm_report to confirm though.

> 
> Is there a method to easily describe the limitation of the resource to remote node?
> 
>  * As one means, we know that the placement of the resource goes well by dividing the first CLI file into two.
>    * After a cluster sent CLI which remote node starts, I send CLI where a cluster starts a resource.
>  * However, we do not want to divide CLI file into two if possible.
> 
> Best Regards,
> Hideo Yamauchi.
> 
> 
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