[ClusterLabs] Antw: Re: Notification agent and Notification recipients
Sriram
sriram.ec at gmail.com
Mon Aug 14 13:19:50 UTC 2017
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 ?
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/
> alert_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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