[ClusterLabs] Colocation by Node

[Andrei Borzenkov]

01.10.2018 18:23, Ken Gaillot пишет:
> On Mon, 2018-10-01 at 11:09 -0400, Marc Smith wrote:
>> Hi,
>>
>> I'm looking for the correct constraint setup to use for the following
>> resource configuration:
>> --snip--
>> node 1: tgtnode2.parodyne.com
>> node 2: tgtnode1.parodyne.com
>> primitive p_iscsi_tgtnode1 iscsi \
>>         params portal=172.16.0.12 target=tgtnode2_redirect udev=no
>> try_recovery=true \
>>         op start interval=0 timeout=120 \
>>         op stop interval=0 timeout=120 \
>>         op monitor interval=120 timeout=30
>> primitive p_iscsi_tgtnode2 iscsi \
>>         params portal=172.16.0.11 target=tgtnode1_redirect udev=no
>> try_recovery=true \
>>         op start interval=0 timeout=120 \
>>         op stop interval=0 timeout=120 \
>>         op monitor interval=120 timeout=30
>> primitive p_scst ocf:esos:scst \
>>         params alua=false \
>>         op start interval=0 timeout=120 \
>>         op stop interval=0 timeout=90 \
>>         op monitor interval=30 timeout=60
>> clone clone_scst p_scst \
>>         meta interleave=true target-role=Started
>> location l_iscsi_tgtnode1 p_iscsi_tgtnode1 role=Started -inf:
>> tgtnode2.parodyne.com
>> location l_iscsi_tgtnode2 p_iscsi_tgtnode2 role=Started -inf:
>> tgtnode1.parodyne.com
>> property cib-bootstrap-options: \
>>         have-watchdog=false \
>>         dc-version=1.1.16-94ff4df \
>>         cluster-infrastructure=corosync \
>>         stonith-enabled=false \
>>         cluster-name=redirect_test \
>>         last-lrm-refresh=1538405190
>> --snip--
>>
>> The gist of it is the 'ocf:esos:scst' provides an iSCSI target
>> interface that each opposing node connects to (just a two node
>> cluster) via 'ocf:heartbeat:iscsi' on each node. I have location
>> constraints in the above configuration that force the
>> "p_iscsi_tgtnode1" and "p_iscsi_tgtnode2" primitives to the correct
>> node, but what I'm lacking is a colocation constraint that prevents
>> "p_iscsi_tgtnode1" from starting unless "clone_scst" is running on
>> the opposing node and vice versa.
>>
>> Is a configuration like this possible? Without creating two
>> primitives for 'ocf:esos:scst' and ditching the clone rule? Or is the
> 
> No, there's no way to constrain against a particular clone instance.

Hmm ...

commit 6ebb25aaa749903b77ad810c8b100745bb3f2a5f
Author: Andrew Beekhof <andrew at beekhof.net>
Date:   Fri Apr 30 15:01:25 2010 +0200

    Medium: PE: Bug lf#2169 - Allow constraints to apply to specific
instances of clones (regression tests)

It does not appear to be documented anywhere and I am not even sure
whether it is enabled by default, but code appears to be there.

> Using separate primitives would be your best bet.
> 
>> best route creating two separate primitives for 'ocf:esos:scst' and
>> then adding more constraints to prevent these from running on the
>> same node and forcing their node "ownership"?
>>
>> Any help / guidance / advice would be greatly appreciated.
>>
>>
>> Thanks,
>>
>> Marc
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