[ClusterLabs] Colocation by Node

[Ken Gaillot]

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.
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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-- 
Ken Gaillot <kgaillot at redhat.com>