[Pacemaker] ClusterMon Resource starting multiple instances of crm_mon

[Andrew Beekhof]

On 10/05/2013, at 12:40 AM, Steven Bambling <smbambling at arin.net> wrote:

> I'm having some issues with getting some cluster  monitoring setup and configured on a 3 node multi-state cluster.   I'm using Florian's blog as an example http://floriancrouzat.net/2013/01/monitor-a-pacemaker-cluster-with-ocfpacemakerclustermon-andor-external-agent/.
> 
> When I create the primitive resource it starts on one of my nodes but spawns multiple instances of crm_mon.  I don't see any reason that would cause it to spawn multiple instances, its very odd behavior.

If you run:

/usr/sbin/crm_mon -p /tmp/ClusterMon_SNMPMon.pid -d -i 0 -E /usr/local/bin/pcmk_snmp_helper.sh -e zen.arin.net -h /tmp/ClusterMon_SNMPMon.html

manually a few times, what happens?  Multiple processes?

> 
> I was also looking for some clarification on what this resource provides….it looks to me that it kicks off a crm_mon in daemon mode that will update a .html file and with -E it will run an external script.  But the resource itself doesn't trigger anything if another resource changes state only if the crm_mon process ( monitored with PID ) fails and it has to restart.

Correct, it just updates the html file which you can see in your browser.
Or, with -E, it can send an email or snmp alert.

>  If this is correct what is the best practice for monitoring additional resource states?

Define "additional"?
If the resource fails we'll normally recover it automatically.

> 
> v/r
> 
> STEVE
> 
> 
> Below are some additional data points. 
> 
> 
> Creating the Resource
> 
> [root at pgdb2 tmp]# crm configure primitive SNMPMon ocf:pacemaker:ClusterMon \
> >         params user="root" update="30" extra_options="-E /usr/local/bin/pcmk_snmp_helper.sh -e zen.arin.net" \
> >         op monitor on-fail="restart" interval="60"
> 
> 
> Manual crm_mon output
> 
> Last updated: Thu May  9 10:24:30 2013
> Last change: Thu May  9 10:20:49 2013 via cibadmin on pgdb2.example.com
> Stack: cman
> Current DC: pgdb1.example.com - partition with quorum
> Version: 1.1.8-7.el6-394e906
> 3 Nodes configured, unknown expected votes
> 6 Resources configured.
> 
> 
> Node pgdb1.example.com: standby
> Online: [ pgdb2.example.com pgdb3.example.com ]
> 
>  PG_REP_VIP	(ocf::heartbeat:IPaddr2):	Started pgdb2.example.com
>  PG_CLI_VIP	(ocf::heartbeat:IPaddr2):	Started pgdb2.example.com
>  Master/Slave Set: msPGSQL [PGSQL]
>      Masters: [ pgdb2.example.com ]
>      Slaves: [ pgdb3.example.com ]
>      Stopped: [ PGSQL:2 ]
>  SNMPMon	(ocf::pacemaker:ClusterMon):	Started pgdb3.example.com
> 
> PS to check for process on pgdb3
> 
> [root at pgdb3 tmp]# ps aux | grep crm_mon
> root     16097  0.0  0.0  82624  2784 ?        S    10:20   0:00 /usr/sbin/crm_mon -p /tmp/ClusterMon_SNMPMon.pid -d -i 0 -E /usr/local/bin/pcmk_snmp_helper.sh -e zen.arin.net -h /tmp/ClusterMon_SNMPMon.html
> root     16099  0.0  0.0  82624  2660 ?        S    10:20   0:00 /usr/sbin/crm_mon -p /tmp/ClusterMon_SNMPMon.pid -d -i 0 -E /usr/local/bin/pcmk_snmp_helper.sh -e zen.arin.net -h /tmp/ClusterMon_SNMPMon.html
> root     16104  0.0  0.0  82624  2448 ?        S    10:20   0:00 /usr/sbin/crm_mon -p /tmp/ClusterMon_SNMPMon.pid -d -i 0 -E /usr/local/bin/pcmk_snmp_helper.sh -e zen.arin.net -h /tmp/ClusterMon_SNMPMon.html
> root     16515  0.0  0.0 103244   852 pts/0    S+   10:21   0:00 grep crm_mon
> 
> Output from corosync.log
> 
> May 09 10:20:51 [3100] pgdb3.cha.arin.net       lrmd:     info: process_lrmd_get_rsc_info:      Resource 'SNMPMon' not found (3 active resources)
> May 09 10:20:51 [3100] pgdb3.cha.arin.net       lrmd:     info: process_lrmd_rsc_register:      Added 'SNMPMon' to the rsc list (4 active resources)
> May 09 10:20:52 [3103] pgdb3.cha.arin.net       crmd:     info: services_os_action_execute:     Managed ClusterMon_meta-data_0 process 16010 exited with rc=0
> May 09 10:20:52 [3103] pgdb3.cha.arin.net       crmd:   notice: process_lrm_event:      LRM operation SNMPMon_monitor_0 (call=61, rc=7, cib-update=28, confirmed=true) not running
> May 09 10:20:52 [3103] pgdb3.cha.arin.net       crmd:   notice: process_lrm_event:      LRM operation SNMPMon_start_0 (call=64, rc=0, cib-update=29, confirmed=true) ok
> May 09 10:20:52 [3103] pgdb3.cha.arin.net       crmd:   notice: process_lrm_event:      LRM operation SNMPMon_monitor_60000 (call=67, rc=0, cib-update=30, confirmed=false) ok
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