[ClusterLabs] EXTERNAL: Re: Pacemaker not reacting as I would expect when two resources fail at the same time

Harvey Shepherd Harvey.Shepherd at Aviatnet.com
Fri Jun 7 22:12:28 EDT 2019


Thank you for your advice Ken. Sorry for the delayed reply - I was trying out a few things and trying to capture extra info. The changes that you suggested make sense, and I have incorporated them into my config. However, the original issue remains whereby Pacemaker does not attempt to restart the failed m_main_system process. I tried setting the migration-threshold of that resource to 1, to try to get Pacemaker to force it to be promoted on the other node, but this had no effect - the master instance remains "failed" and the slave instance remains "running" but is not promoted. Snipped output from crm_mon:

Current DC: primary (version unknown) - partition with quorum
Last updated: Sat Jun  8 02:04:05 2019
Last change: Sat Jun  8 01:51:25 2019 by hacluster via crmd on primary

2 nodes configured
26 resources configured

Online: [ primary secondary ]

Active resources:

 Clone Set: m_main_system [main_system] (promotable)
     main_system      (ocf::main_system-ocf):    FAILED secondary
     Slaves: [ primary ]

Migration Summary:
* Node secondary:
   main_system: migration-threshold=1 fail-count=1 last-failure='Sat Jun  8 01:52:08 2019'

Failed Resource Actions:
* main_system_monitor_10000 on secondary 'unknown error' (1): call=214, status=complete, exitreason='',
    last-rc-change='Sat Jun  8 01:52:08 2019', queued=0ms, exec=0ms


>From the logs I see:

2019 Jun  8 01:52:09.574 daemon.warning VIRTUAL pacemaker-schedulerd 1131  warning: Processing failed monitor of main_system:1 on secondary: unknown error 
2019 Jun  8 01:52:09.586 daemon.warning VIRTUAL pacemaker-schedulerd 1131  warning: Forcing m_main_system away from secondary after 1 failures (max=1)
2019 Jun  8 01:52:09.586 daemon.warning VIRTUAL pacemaker-schedulerd 1131  warning: Forcing m_main_system away from secondary after 1 failures (max=1)
2019 Jun  8 01:52:10.692 daemon.warning VIRTUAL pacemaker-controld 1132  warning: Transition 35 (Complete=33, Pending=0, Fired=0, Skipped=0, Incomplete=67, Source=/var/lib/pacemaker/pengine/pe-input-47.bz2): Terminated
2019 Jun  8 01:52:10.692 daemon.warning VIRTUAL pacemaker-controld 1132  warning: Transition failed: terminated


Do you have any further suggestions? For your information I've upgraded Pacemaker to 2.0.2, but the behaviour is the same.

Thanks,
Harvey
________________________________________
From: Users <users-bounces at clusterlabs.org> on behalf of Ken Gaillot <kgaillot at redhat.com>
Sent: Saturday, 1 June 2019 5:40 a.m.
To: Cluster Labs - All topics related to open-source clustering welcomed
Subject: EXTERNAL: Re: [ClusterLabs] Pacemaker not reacting as I would expect when two resources fail at the same time

On Thu, 2019-05-30 at 23:39 +0000, Harvey Shepherd wrote:
> Hi All,
>
> I'm running Pacemaker 2.0.1 on a cluster containing two nodes; one
> master and one slave. I have a main master/slave resource
> (m_main_system), a group of resources that run in active-active mode
> (active_active - i.e. run on both nodes), and a group that runs in
> active-disabled mode (snmp_active_disabled - resources only run on
> the current promoted master). The snmp_active_disabled group is
> configured to be co-located with the master of m_main_system, so only
> a failure of the master m_main_system resource can trigger a
> failover. The constraints specify that m_main_system must be started
> before snmp_active_disabled.
>
> The problem I'm having is that when a resource in the
> snmp_active_disabled group fails and gets into a constant cycle where
> Pacemaker tries to restart it, and I then kill m_main_system on the
> master, then Pacemaker still constantly tries to restart the failed
> snmp_active_disabled resource and ignores the more important
> m_main_system process which should be triggering a failover. If I
> stabilise the snmp_active_disabled resource then Pacemaker finally
> acts on the m_main_system failure. I hope I've described this well
> enough, but I've included a cut down form of my CIB config below if
> it helps!
>
> Is this a bug or an error in my config? Perhaps the order in which
> the groups are defined in the CIB matters despite the constraints?
> Any help would be gratefully received.
>
> Thanks,
> Harvey
>
> <configuration>
>   <crm_config>
>     <cluster_property_set id="cib-bootstrap-options">
>       <nvpair name="stonith-enabled" value="false" id="cib-bootstrap-
> options-stonith-enabled"/>
>       <nvpair name="no-quorum-policy" value="ignore" id="cib-
> bootstrap-options-no-quorum-policy"/>
>       <nvpair name="have-watchdog" value="false" id="cib-bootstrap-
> options-have-watchdog"/>
>       <nvpair name="cluster-name" value="lbcluster" id="cib-
> bootstrap-options-cluster-name"/>
>       <nvpair name="start-failure-is-fatal" value="false" id="cib-
> bootstrap-options-start-failure-is-fatal"/>
>       <nvpair name="cluster-recheck-interval" value="0s" id="cib-
> bootstrap-options-cluster-recheck-interval"/>
>     </cluster_property_set>
>   </crm_config>
>   <nodes>
>     <node id="1" uname="primary"/>
>     <node id="2" uname="secondary"/>
>   </nodes>
>   <resources>
>     <group id="snmp_active_disabled">
>         <primitive id="snmpd" class="lsb" type="snmpd">
>           <operations>
>             <op name="monitor" interval="10s" id="snmpd-monitor-
> 10s"/>
>             <op name="start" interval="0" timeout="30s" id="snmpd-
> start-30s"/>
>             <op name="stop" interval="0" timeout="30s" id="snmpd-
> stop-30s"/>
>           </operations>
>         </primitive>
>         <primitive id="snmp-auxiliaries" class="lsb" type="snmp-
> auxiliaries">
>           <operations>
>             <op name="monitor" interval="10s" id="snmp-auxiliaries-
> monitor-10s"/>
>             <op name="start" interval="0" timeout="30s" id="snmp-
> auxiliaries-start-30s"/>
>             <op name="stop" interval="0" timeout="30s" id="snmp-
> auxiliaries-stop-30s"/>
>           </operations>
>         </primitive>
>     </group>
>     <clone id="clone_active_active">
>       <meta_attributes id="clone_active_active_meta_attributes">
>         <nvpair id="group-unique" name="globally-unique"
> value="false"/>
>       </meta_attributes>
>       <group id="active_active">
>         <primitive id="logd" class="lsb" type="logd">
>           <operations>
>             <op name="monitor" interval="10s" id="logd-monitor-10s"/>
>             <op name="start" interval="0" timeout="30s" id="logd-
> start-30s"/>
>             <op name="stop" interval="0" timeout="30s" id="logd-stop-
> 30s"/>
>           </operations>
>         </primitive>
>         <primitive id="serviced" class="lsb" type="serviced">
>           <operations>
>             <op name="monitor" interval="10s" id="serviced-monitor-
> 10s"/>
>             <op name="start" interval="0" timeout="30s" id="serviced-
> start-30s"/>
>             <op name="stop" interval="0" timeout="30s" id="serviced-
> stop-30s"/>
>           </operations>
>         </primitive>
>       </group>
>     </clone>
>     <master id="m_main_system">
>       <meta_attributes id="m_main_system-meta_attributes">
>         <nvpair name="notify" value="true" id="m_main_system-
> meta_attributes-notify"/>
>         <nvpair name="clone-max" value="2" id="m_main_system-
> meta_attributes-clone-max"/>
>         <nvpair name="promoted-max" value="1" id="m_main_system-
> meta_attributes-promoted-max"/>
>         <nvpair name="promoted-node-max" value="1" id="m_main_system-
> meta_attributes-promoted-node-max"/>
>       </meta_attributes>
>       <primitive id="main_system" class="ocf" provider="acme"
> type="main-system-ocf">
>         <operations>
>           <op name="start" interval="0" timeout="120s"
> id="main_system-start-0"/>
>           <op name="stop" interval="0" timeout="120s"
> id="main_system-stop-0"/>
>           <op name="promote" interval="0" timeout="120s"
> id="main_system-promote-0"/>
>           <op name="demote" interval="0" timeout="120s"
> id="main_system-demote-0"/>
>           <op name="monitor" interval="10s" timeout="10s"
> role="Master" id="main_system-monitor-10s"/>
>           <op name="monitor" interval="11s" timeout="10s"
> role="Slave" id="main_system-monitor-11s"/>
>           <op name="notify" interval="0" timeout="60s"
> id="main_system-notify-0"/>
>          </operations>
>        </primitive>
>     </master>
>   </resources>
>   <constraints>
>     <rsc_colocation id="master_only_snmp_rscs_with_main_system"
> score="INFINITY" rsc="snmp_active_disabled" with-rsc="m_main_system"
> with-rsc-role="Master"/>
>     <rsc_order id="snmp_active_disabled_after_main_system"
> kind="Mandatory" first="m_main_system" then="snmp_active_disabled"/>

You want first-action="promote" in the above constraint, otherwise the
slave being started (or the master being started but not yet promoted)
is sufficient to start snmp_active_disabled (even though the colocation
ensures it will only be started on the same node where the master will
be).

I'm not sure if that's related to your issue, but it's worth trying
first.

>     <rsc_order id="active_active_after_main_system" kind="Mandatory"
> first="m_main_system" then="clone_active_active"/>

You may also want to set interleave to true on clone_active_active, if
you want it to depend only on the local instance of m_main_system, and
not both instances.

>   </constraints>
>   <rsc_defaults>
>     <meta_attributes id="rsc-options">
>       <nvpair name="resource-stickiness" value="1" id="rsc-options-
> resource-stickiness"/>
>       <nvpair name="migration-threshold" value="0" id="rsc-options-
> migration-threshold"/>
>       <nvpair name="requires" value="nothing" id="rsc-options-
> requires"/>
>     </meta_attributes>
>   </rsc_defaults>
> </configuration>
--
Ken Gaillot <kgaillot at redhat.com>

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