[ClusterLabs] Antw: Re: Notification agent and Notification recipients
Sriram
sriram.ec at gmail.com
Tue Aug 15 07:51:22 UTC 2017
Thanks for clarifying.
Regards,
Sriram.
On Mon, Aug 14, 2017 at 7:34 PM, Klaus Wenninger <kwenning at redhat.com>
wrote:
> On 08/14/2017 03:19 PM, Sriram wrote:
>
> Yes, I had precreated the script file with the required permission.
>
> [root@*node1* alerts]# ls -l /usr/share/pacemaker/alert_file.sh
> -rwxr-xr-x. 1 root root 4140 Aug 14 01:51 /usr/share/pacemaker/alert_
> file.sh
> [root@*node2* alerts]# ls -l /usr/share/pacemaker/alert_file.sh
> -rwxr-xr-x. 1 root root 4139 Aug 14 01:51 /usr/share/pacemaker/alert_
> file.sh
> [root@*node3* alerts]# ls -l /usr/share/pacemaker/alert_file.sh
> -rwxr-xr-x. 1 root root 4139 Aug 14 01:51 /usr/share/pacemaker/alert_
> file.sh
>
> Later I observed that user "hacluster" is not able to create the log file
> under /usr/share/pacemaker/alert_file.log.
> I am sorry, I should have observed this in the log before posting the
> query. Then I gave the path as /tmp/alert_file.log, it is able to create
> now.
> Thanks for pointing it out.
>
> I have one more clarification,
>
> if the resource is running in node2,
> [root at node2 tmp]# pcs resource
> TRR (ocf::heartbeat:TimingRedundancyRA): Started node2
>
> And I executed the below command to make it standby.
> [root at node2 tmp] # pcs node standby node2
>
> Resource shifted to node3, because of higher location constraint.
> [root at node2 tmp]# pcs resource
> TRR (ocf::heartbeat:TimingRedundancyRA): Started node3.
>
>
> I got the log file created under node2(resource stopped) and
> node3(resource started).
>
> Node1 was not notified about the resource shift, I mean no log file was
> created there.
> Its because alerts are designed to notify the external agents about the
> cluster events. Its not for internal notifications.
>
> Is my understanding correct ?
>
>
> Quite simple: crmd of node1 just didn't have anything to do with shifting
> the resource
> from node2 -> node3. There is no additional information passed between the
> nodes
> just to create a full set of notifications on every node. If you want to
> have a full log
> (or whatever you altert-agent is doing) in one place this would be up to
> your alert-agent.
>
>
> Regards,
> Klaus
>
>
> Regards,
> Sriram.
>
>
>
> On Mon, Aug 14, 2017 at 5:42 PM, Klaus Wenninger <kwenning at redhat.com>
> wrote:
>
>> On 08/14/2017 12:32 PM, Sriram wrote:
>>
>> Hi Ken,
>>
>> I used the alerts as well, seems to be not working.
>>
>> Please check the below configuration
>> [root at node1 alerts]# pcs config show
>> Cluster Name:
>> Corosync Nodes:
>> Pacemaker Nodes:
>> node1 node2 node3
>>
>> Resources:
>> Resource: TRR (class=ocf provider=heartbeat type=TimingRedundancyRA)
>> Operations: start interval=0s timeout=60s (TRR-start-interval-0s)
>> stop interval=0s timeout=20s (TRR-stop-interval-0s)
>> monitor interval=10 timeout=20 (TRR-monitor-interval-10)
>>
>> Stonith Devices:
>> Fencing Levels:
>>
>> Location Constraints:
>> Resource: TRR
>> Enabled on: node1 (score:100) (id:location-TRR-node1-100)
>> Enabled on: node2 (score:200) (id:location-TRR-node2-200)
>> Enabled on: node3 (score:300) (id:location-TRR-node3-300)
>> Ordering Constraints:
>> Colocation Constraints:
>> Ticket Constraints:
>>
>> Alerts:
>> Alert: alert_file (path=/usr/share/pacemaker/alert_file.sh)
>> Options: debug_exec_order=false
>> Meta options: timeout=15s
>> Recipients:
>> Recipient: recipient_alert_file_id (value=/usr/share/pacemaker/al
>> ert_file.log)
>>
>>
>> Did you pre-create the file with proper rights? Be aware that the
>> alert-agent
>> is called as user hacluster.
>>
>>
>> Resources Defaults:
>> resource-stickiness: INFINITY
>> Operations Defaults:
>> No defaults set
>>
>> Cluster Properties:
>> cluster-infrastructure: corosync
>> dc-version: 1.1.15-11.el7_3.4-e174ec8
>> default-action-timeout: 240
>> have-watchdog: false
>> no-quorum-policy: ignore
>> placement-strategy: balanced
>> stonith-enabled: false
>> symmetric-cluster: false
>>
>> Quorum:
>> Options:
>>
>>
>> /usr/share/pacemaker/alert_file.sh does not get called whenever I
>> trigger a scenario for failover.
>> Please let me know if I m missing anything.
>>
>>
>> Do you get any logs - like for startup of resources - or nothing at all?
>>
>> Regards,
>> Klaus
>>
>>
>>
>>
>> Regards,
>> Sriram.
>>
>> On Tue, Aug 8, 2017 at 8:29 PM, Ken Gaillot <kgaillot at redhat.com> wrote:
>>
>>> On Tue, 2017-08-08 at 17:40 +0530, Sriram wrote:
>>> > Hi Ulrich,
>>> >
>>> >
>>> > Please see inline.
>>> >
>>> > On Tue, Aug 8, 2017 at 2:01 PM, Ulrich Windl
>>> > <Ulrich.Windl at rz.uni-regensburg.de> wrote:
>>> > >>> Sriram <sriram.ec at gmail.com> schrieb am 08.08.2017 um
>>> > 09:30 in Nachricht
>>> > <CAMvdjurcQc6t=ZfGr=cRL25Xq0Je9h9F_TvZXyxVAn3n
>>> > +Dvcgw at mail.gmail.com>:
>>> > > Hi Ken & Jan,
>>> > >
>>> > > In the cluster we have, there is only one resource running.
>>> > Its a OPT-IN
>>> > > cluster with resource-stickiness set to INFINITY.
>>> > >
>>> > > Just to clarify my question, lets take a scenario where
>>> > there are four
>>> > > nodes N1, N2, N3, N4
>>> > > a. N1 comes up first, starts the cluster.
>>> >
>>> > The cluster will start once it has a quorum.
>>> >
>>> > > b. N1 Checks that there is no resource running, so it will
>>> > add the
>>> > > resource(R) with the some location constraint(lets say score
>>> > 100)
>>> > > c. So Resource(R) runs in N1 now.
>>> > > d. N2 comes up next, checks that resource(R) is already
>>> > running in N1, so
>>> > > it will update the location constraint(lets say score 200)
>>> > > e. N3 comes up next, checks that resource(R) is already
>>> > running in N1, so
>>> > > it will update the location constraint(lets say score 300)
>>> >
>>> > See my remark on quorum above.
>>> >
>>> > Yes you are right, I forgot to mention it.
>>> >
>>> >
>>> > > f. N4 comes up next, checks that resource(R) is already
>>> > running in N1, so
>>> > > it will update the location constraint(lets say score 400)
>>> > > g. For the some reason, if N1 goes down, resource(R) shifts
>>> > to N4(as its
>>> > > score is higher than anyone).
>>> > >
>>> > > In this case is it possible to notify the nodes N2, N3 that
>>> > newly elected
>>> > > active node is N4 ?
>>> >
>>> > What type of notification, and what would the node do with it?
>>> > Any node in the cluster always has up to date configuration
>>> > information. So it knows the status of the other nodes also.
>>> >
>>> >
>>> > I agree that the node always has upto date configuration information,
>>> > but an application or a thread needs to poll for that information. Is
>>> > there any way, where the notifications are received through some
>>> > action function in RA. ?
>>>
>>> Ah, I misunderstood your situation, I thought you had a cloned resource.
>>>
>>> For that, the alerts feature (available in Pacemaker 1.1.15 and later)
>>> might be useful:
>>>
>>> http://clusterlabs.org/doc/en-US/Pacemaker/1.1-pcs/html-sing
>>> le/Pacemaker_Explained/index.html#idm139900098676896
>>>
>>>
>>> >
>>> >
>>> > Regards,
>>> > Sriram.
>>> >
>>> > >
>>> > > I went through clone notifications and master-slave, Iooks
>>> > like it either
>>> > > requires identical resources(Anonymous) or Unique or
>>> > Stateful resources to
>>> > > be running
>>> > > in all the nodes of the cluster, where as in our case there
>>> > is only
>>> > > resource running in the whole cluster.
>>> >
>>> > Maybe the main reason for not having notifications is that if
>>> > a node fails hard, it won't be able to send out much status
>>> > information to the other nodes.
>>> >
>>> > Regards,
>>> > Ulrich
>>> >
>>> > >
>>> > > Regards,
>>> > > Sriram.
>>> > >
>>> > >
>>> > >
>>> > >
>>> > > On Mon, Aug 7, 2017 at 11:28 AM, Sriram
>>> > <sriram.ec at gmail.com> wrote:
>>> > >
>>> > >>
>>> > >> Thanks Ken, Jan. Will look into the clone notifications.
>>> > >>
>>> > >> Regards,
>>> > >> Sriram.
>>> > >>
>>> > >> On Sat, Aug 5, 2017 at 1:25 AM, Ken Gaillot
>>> > <kgaillot at redhat.com> wrote:
>>> > >>
>>> > >>> On Thu, 2017-08-03 at 12:31 +0530, Sriram wrote:
>>> > >>> >
>>> > >>> > Hi Team,
>>> > >>> >
>>> > >>> >
>>> > >>> > We have a four node cluster (1 active : 3 standby) in
>>> > our lab for a
>>> > >>> > particular service. If the active node goes down, one of
>>> > the three
>>> > >>> > standby node becomes active. Now there will be (1
>>> > active : 2
>>> > >>> > standby : 1 offline).
>>> > >>> >
>>> > >>> >
>>> > >>> > Is there any way where this newly elected node sends
>>> > notification to
>>> > >>> > the remaining 2 standby nodes about its new status ?
>>> > >>>
>>> > >>> Hi Sriram,
>>> > >>>
>>> > >>> This depends on how your service is configured in the
>>> > cluster.
>>> > >>>
>>> > >>> If you have a clone or master/slave resource, then clone
>>> > notifications
>>> > >>> is probably what you want (not alerts, which is the path
>>> > you were going
>>> > >>> down -- alerts are designed to e.g. email a system
>>> > administrator after
>>> > >>> an important event).
>>> > >>>
>>> > >>> For details about clone notifications, see:
>>> > >>>
>>> > >>>
>>> > http://clusterlabs.org/doc/en-US/Pacemaker/1.1-pcs/html-sing
>>> > >>>
>>> > le/Pacemaker_Explained/index.html#_clone_resource_agent_req
>>> uirements
>>> > >>>
>>> > >>> The RA must support the "notify" action, which will be
>>> > called when a
>>> > >>> clone instance is started or stopped. See the similar
>>> > section later for
>>> > >>> master/slave resources for additional information. See the
>>> > mysql or
>>> > >>> pgsql resource agents for examples of notify
>>> > implementations.
>>> > >>>
>>> > >>> > I was exploring "notification agent" and "notification
>>> > recipient"
>>> > >>> > features, but that doesn't seem to
>>> > work. /etc/sysconfig/notify.sh
>>> > >>> > doesn't get invoked even in the newly elected active
>>> > node.
>>> > >>>
>>> > >>> Yep, that's something different altogether -- it's only
>>> > enabled on RHEL
>>> > >>> systems, and solely for backward compatibility with an
>>> > early
>>> > >>> implementation of the alerts interface. The new alerts
>>> > interface is more
>>> > >>> flexible, but it's not designed to send information
>>> > between cluster
>>> > >>> nodes -- it's designed to send information to something
>>> > external to the
>>> > >>> cluster, such as a human, or an SNMP server, or a
>>> > monitoring system.
>>> > >>>
>>> > >>>
>>> > >>> > Cluster Properties:
>>> > >>> > cluster-infrastructure: corosync
>>> > >>> > dc-version: 1.1.17-e2e6cdce80
>>> > >>> > default-action-timeout: 240
>>> > >>> > have-watchdog: false
>>> > >>> > no-quorum-policy: ignore
>>> > >>> > notification-agent: /etc/sysconfig/notify.sh
>>> > >>> > notification-recipient: /var/log/notify.log
>>> > >>> > placement-strategy: balanced
>>> > >>> > stonith-enabled: false
>>> > >>> > symmetric-cluster: false
>>> > >>> >
>>> > >>> >
>>> > >>> >
>>> > >>> >
>>> > >>> > I m using the following versions of pacemaker and
>>> > corosync.
>>> > >>> >
>>> > >>> >
>>> > >>> > /usr/sbin # ./pacemakerd --version
>>> > >>> > Pacemaker 1.1.17
>>> > >>> > Written by Andrew Beekhof
>>> > >>> > /usr/sbin # ./corosync -v
>>> > >>> > Corosync Cluster Engine, version '2.3.5'
>>> > >>> > Copyright (c) 2006-2009 Red Hat, Inc.
>>> > >>> >
>>> > >>> >
>>> > >>> > Can you please suggest if I m doing anything wrong or if
>>> > there any
>>> > >>> > other mechanisms to achieve this ?
>>> > >>> >
>>> > >>> >
>>> > >>> > Regards,
>>> > >>> > Sriram.
>>>
>>> --
>>> Ken Gaillot <kgaillot at redhat.com>
>>>
>>>
>>>
>>>
>>>
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>>
>>
>>
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