[Pacemaker] Network outage debugging

Sean Lutner sean at rentul.net
Wed Nov 13 14:24:46 UTC 2013 

On Nov 13, 2013, at 3:15 AM, Jan Friesse <jfriesse at redhat.com> wrote:

> Andrew Beekhof napsal(a):
>> 
>> On 13 Nov 2013, at 11:49 am, Sean Lutner <sean at rentul.net> wrote:
>> 
>>> 
>>> 
>>>> On Nov 12, 2013, at 7:33 PM, Andrew Beekhof
>>>> <andrew at beekhof.net> wrote:
>>>> 
>>>> 
>>>>> On 13 Nov 2013, at 11:22 am, Sean Lutner <sean at rentul.net>
>>>>> wrote:
>>>>> 
>>>>> 
>>>>> 
>>>>>> On Nov 12, 2013, at 6:01 PM, Andrew Beekhof
>>>>>> <andrew at beekhof.net> wrote:
>>>>>> 
>>>>>> 
>>>>>>> On 13 Nov 2013, at 6:10 am, Sean Lutner <sean at rentul.net>
>>>>>>> wrote:
>>>>>>> 
>>>>>>> The folks testing the cluster I've been building have run
>>>>>>> a script which blocks all traffic except SSH on one node
>>>>>>> of the cluster for 15 seconds to mimic a network failure.
>>>>>>> During this time, the network being "down" seems to cause
>>>>>>> some odd behavior from pacemaker resulting in it dying.
>>>>>>> 
>>>>>>> The cluster is two nodes and running four custom
>>>>>>> resources on EC2 instances. The OS is CentOS 6.4 with the
>>>>>>> config below:
>>>>>>> 
>>>>>>> I've attached the /var/log/messages and
>>>>>>> /var/log/cluster/corosync.log from the time period during
>>>>>>> the test. I've having some difficulty in piecing together
>>>>>>> what happened and am hoping someone can shed some light
>>>>>>> on the problem. Any indications why pacemaker is dying on
>>>>>>> that node?
>>>>>> 
>>>>>> Because corosync is dying underneath it:
>>>>>> 
>>>>>> Nov 09 14:51:49 [942] ip-10-50-3-251        cib:    error:
>>>>>> send_ais_text:    Sending message 28 via cpg: FAILED
>>>>>> (rc=2): Library error: Connection timed out (110) Nov 09
>>>>>> 14:51:49 [942] ip-10-50-3-251        cib:    error:
>>>>>> pcmk_cpg_dispatch:    Connection to the CPG API failed: 2 
>>>>>> Nov 09 14:51:49 [942] ip-10-50-3-251        cib:    error:
>>>>>> cib_ais_destroy:    Corosync connection lost!  Exiting. Nov
>>>>>> 09 14:51:49 [942] ip-10-50-3-251        cib:     info:
>>>>>> terminate_cib:    cib_ais_destroy: Exiting fast...
>>>>> 
>>>>> Is that the expected behavior?
>>>> 
>>>> It is expected behaviour when corosync dies.  Ideally corosync
>>>> wouldn't die though.
>>> 
>>> What other debugging can I do to try to find out why corosync
>>> died?
>> 
>> There are various logging setting that may help. CC'ing Jan to see
>> if he has any suggestions.
>> 
> 
> If corosync really died corosync-fplay output (right after corosync
> death) and coredump are most useful.
> 
> Regards,
>  Honza

So the process to collect this would be:

- Run the test
- Watch the logs for corosync to die
- Run corosync-fplay and capture the output (will corosync-fplay > file.out suffice?)
- Capture a core dump from corosync 

How do I capture the core dump? Is it something that has to be enabled in the /etc/corosync/corosync.conf file first and then run the tests? I've not done this in the past.

Thanks

> 
>>> 
>>> Thanks
>>> 
>>>> 
>>>>> Is it because the DC was the other node?
>>>> 
>>>> No.
>>>> 
>>>>> 
>>>>> I did notice that there was an attempted fence operation but
>>>>> it didn't look successful.
>>>>> 
>>>>>> 
>>>>>> 
>>>>>>> 
>>>>>>> 
>>>>>>> [root at ip-10-50-3-122 ~]# pcs config Corosync Nodes:
>>>>>>> 
>>>>>>> Pacemaker Nodes: ip-10-50-3-122 ip-10-50-3-251
>>>>>>> 
>>>>>>> Resources: Resource: ClusterEIP_54.215.143.166
>>>>>>> (provider=pacemaker type=EIP class=ocf) Attributes:
>>>>>>> first_network_interface_id=eni-e4e0b68c
>>>>>>> second_network_interface_id=eni-35f9af5d
>>>>>>> first_private_ip=10.50.3.191 second_private_ip=10.50.3.91
>>>>>>> eip=54.215.143.166 alloc_id=eipalloc-376c3c5f interval=5s
>>>>>>> Operations: monitor interval=5s Clone:
>>>>>>> EIP-AND-VARNISH-clone Group: EIP-AND-VARNISH Resource:
>>>>>>> Varnish (provider=redhat type=varnish.sh class=ocf) 
>>>>>>> Operations: monitor interval=5s Resource: Varnishlog
>>>>>>> (provider=redhat type=varnishlog.sh class=ocf) 
>>>>>>> Operations: monitor interval=5s Resource: Varnishncsa
>>>>>>> (provider=redhat type=varnishncsa.sh class=ocf) 
>>>>>>> Operations: monitor interval=5s Resource: ec2-fencing
>>>>>>> (type=fence_ec2 class=stonith) Attributes:
>>>>>>> ec2-home=/opt/ec2-api-tools pcmk_host_check=static-list
>>>>>>> pcmk_host_list=HA01 HA02 Operations: monitor
>>>>>>> start-delay=30s interval=0 timeout=150s
>>>>>>> 
>>>>>>> Location Constraints: Ordering Constraints: 
>>>>>>> ClusterEIP_54.215.143.166 then Varnish Varnish then
>>>>>>> Varnishlog Varnishlog then Varnishncsa Colocation
>>>>>>> Constraints: Varnish with ClusterEIP_54.215.143.166 
>>>>>>> Varnishlog with Varnish Varnishncsa with Varnishlog
>>>>>>> 
>>>>>>> Cluster Properties: dc-version: 1.1.8-7.el6-394e906 
>>>>>>> cluster-infrastructure: cman last-lrm-refresh:
>>>>>>> 1384196963 no-quorum-policy: ignore stonith-enabled:
>>>>>>> true
>>>>>>> 
>>>>>>> <net-failure-messages-110913.out><net-failure-corosync-110913.out>
>>>>>>> 
>>>>>>> 
> _______________________________________________
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>>>>>>> 
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>>>>>> 
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>>>>>> 
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>>>>> 
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>>>> 
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>>> 
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>> 
> 
> 
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> 
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