[ClusterLabs] can't create master/slave resource

Tiemen Ruiten t.ruiten at rdmedia.com
Wed Sep 20 08:40:31 UTC 2017


Thank you very much for the detailed explanation. We will look for another
way to determine master/slave status of this application then.

On 20 September 2017 at 09:20, Tomas Jelinek <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
>
>
>
>> Regards,
>> Tomas
>>
>> [1]: http://clusterlabs.org/doc/en-US/Pacemaker/1.1-pcs/html-sing
>> le/Pacemaker_Explained/index.html#_requirements_for_multi_
>> state_resource_agents
>> [2]: 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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>>>
>>>
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>>
>
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>



-- 
Tiemen Ruiten
Systems Engineer
R&D Media
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