[ClusterLabs] can't create master/slave resource

Klaus Wenninger kwenning at redhat.com
Wed Sep 20 04:57:54 EDT 2017


On 09/20/2017 10:40 AM, Tiemen Ruiten wrote:
> Thank you very much for the detailed explanation. We will look for
> another way to determine master/slave status of this application then.

What you still could try is to write kind of an ocf-wrapper for your
systemd-service
so that you can leave starting/stopping to systemd (controlled via
systemctl) and
do what is needed on top to control master/slave-state in the
ocf-Resource-Agent.
iirc there have been threads about creating ocf-wrappers of systemd-services
on this mailing-list.

Regards,
Klaus

>
> On 20 September 2017 at 09:20, Tomas Jelinek <tojeline at redhat.com
> <mailto:tojeline at redhat.com>> wrote:
>
>
>
>     Dne 20.9.2017 v 09:03 Tomas Jelinek napsal(a):
>
>         Hi,
>
>         systemd resources cannot be used as master/slave resources. In
>         order to use a resource as a master/slave, the resource must
>         support promote and demote actions [1], which systemd
>         resources don't.
>
>         # pcs resource create test systemd:postfix
>         # pcs resource master test
>         # pcs cluster verify -V
>             error: native_unpack:        Resource test:0 is of type
>         systemd and therefore cannot be used as a master/slave resource
>             error: create_child_clone:   Failed unpacking resource test
>             error: unpack_resources:     Failed unpacking master
>         test-master
>         Errors found during check: config not valid
>
>         You need to use an ocf resource agent (with promote and demote
>         actions implemented) for your resource for this to work.
>
>         Because the resource cannot be unpacked by pacemaker, it is
>         not shown in the "pcs status" output - pcs doesn't get any
>         info about it from pacemaker. This issue has been already
>         discussed. Pacemaker will provide info when such errors occur
>         so pcs will be able to display it. [2]
>
>         The resource may not be running but it is still defined in the
>         configuration:
>         # pcs resource --full
>           Master: test-master
>            Resource: test (class=systemd type=postfix)
>             Operations: monitor interval=60 timeout=100
>         (test-monitor-interval-60)
>                         start interval=0s timeout=100
>         (test-start-interval-0s)
>                         stop interval=0s timeout=100
>         (test-stop-interval-0s)
>
>         That's why you get an error that the id already exists.
>
>
>         I'm going to file a bug against pcs so it won't be possible to
>         master/slave systemd resources as it is not supported anyway.
>
>
>     https://bugzilla.redhat.com/show_bug.cgi?id=1493416
>     <https://bugzilla.redhat.com/show_bug.cgi?id=1493416>
>
>
>
>         Regards,
>         Tomas
>
>         [1]:
>         http://clusterlabs.org/doc/en-US/Pacemaker/1.1-pcs/html-single/Pacemaker_Explained/index.html#_requirements_for_multi_state_resource_agents
>         <http://clusterlabs.org/doc/en-US/Pacemaker/1.1-pcs/html-single/Pacemaker_Explained/index.html#_requirements_for_multi_state_resource_agents>
>
>         [2]: https://bugzilla.redhat.com/show_bug.cgi?id=1447951
>         <https://bugzilla.redhat.com/show_bug.cgi?id=1447951>
>
>
>         Dne 19.9.2017 v 17:13 Tiemen Ruiten napsal(a):
>
>             Hello,
>
>             We have a 3-node cluster (CentOS 7.4) with several systemd
>             resources configured. One of them I would like to create
>             as a master/slave resource, so following the RedHat
>             documentation:
>
>             pcs resource create ivr systemd:japp at ivr - works, the
>             service is started on one of the nodes.
>             pcs resource master ivr-master ivr - doesn't work as
>             expected: the service is stopped and the output of pcs
>             resource show doesn't list it anymore. However, if I try
>             the command again, I get an error saying the resource ivr
>             already exists! I have to delete the resource and recreate
>             it to get the service to run.
>
>             pacemaker-libs-1.1.16-12.el7_4.2.x86_64
>             pacemaker-cluster-libs-1.1.16-12.el7_4.2.x86_64
>             pacemaker-1.1.16-12.el7_4.2.x86_64
>             pacemaker-cli-1.1.16-12.el7_4.2.x86_64
>             corosynclib-2.4.0-9.el7_4.2.x86_64
>             corosync-2.4.0-9.el7_4.2.x86_64
>
>             Am I doing something wrong?
>
>             -- 
>             Tiemen Ruiten
>             Systems Engineer
>             R&D Media
>
>
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>
>
> -- 
> Tiemen Ruiten
> Systems Engineer
> R&D Media
>
>
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-- 
Klaus Wenninger

Senior Software Engineer, EMEA ENG Openstack Infrastructure

Red Hat

kwenning at redhat.com   

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