[Pacemaker] Consider extra slave node resource when calculating actions for failover
Andrew Beekhof
andrew at beekhof.net
Wed Jan 15 00:29:02 EST 2014
On 14 Jan 2014, at 11:25 pm, Juraj Fabo <juraj.fabo at gmail.com> wrote:
> Hi
>
> I have master-slave cluster with configuration attached below.
> It is based on documented postgresql master-slave cluster configuration.
> Colocation constraints should work that way that if some of "master-group"
> resources fails,
> failover to slave node will be done. This basically works ok.
>
> I would like to have an additional condition integrated.
> On and only on the HotStandby runs resource SERVICE-res-mon-s1.
> If the SERVICE-res-mon-s1 resource on slave reports negative score then
> failover should not be done,
> because it indicates that the slave node is not ready to run services from
> master-group.
> However, even if the SERVICE-res-mon-s1 fails, postgresql slave (HotStandby)
> should still run,
> because the SERVICE-res-mon-s1 monitors some application related
> functionality which does not block the postgres itself.
>
> The requested feature is very close to the one described in the
> http://clusterlabs.org/doc/en-
> US/Pacemaker/1.0/html/Pacemaker_Explained/ch09s03s03s02.html
> "prefer nodes with the most connectivity"
>
> with that difference, that the resource agent is running only on the standby
> node.
> Reason is, that the SERVICE-res-mon-s1 is in reality minimalistic
> implementation of the SERVICE-service
> in order to know whether the slave would be able to run the SERVICE-service.
The simplest approach might be to run:
crm_attribute --name postgres --value 100 --node serv1 --lifetime forever
And then have SERVICE-res-mon-s1 run:
crm_attribute --name postgres --value 10 --node serv2 --lifetime reboot
whenever it starts and
crm_attribute --name postgres --delete --node serv2 --lifetime reboot
whenever it stops.
Then you can use the 'postgres' attribute in the same way as you did with 'ping'.
>
> If needed, I could change this design to use clone of SERVICE-res-mon-s1 to
> run them on both nodes, however, I did not succeed even with this
> configuration.
> Next step would be to have multiple instances of this resource agent running
> on both nodes (with different parameter spanID) and preffer node where "more
> spans" are ok.
>
> Ocf agent service_res_check reports the resource availability via "monitor"
> function, where it updates its own score attribute via crm_attribute.
> I thought that using this custom score attribute in location or colocation
> constraint could do the job, but it did not affected the failover logic.
>
> Please, what should be done in order to have the cluster consider also the
> SERVICE-res-mon-s1 results when calculating resources score and "willingnes
> to move"?
>
> note: my pacemaker contains also patch from
> https://github.com/beekhof/pacemaker/commit/58962338
>
> Thank you in advance
>
> node $id="1" serv1 \
> attributes SERVICE-pgsql-data-status="STREAMING|ASYNC"
> node $id="2" serv2 \
> attributes SERVICE-pgsql-data-status="LATEST"
> primitive SERVICE-MIP1 ocf:heartbeat:IPaddr2 \
> params ip="10.40.0.70" cidr_netmask="24" iflabel="ma1" \
> op monitor interval="10s"
> primitive SERVICE-MIP2 ocf:heartbeat:IPaddr2 \
> params ip="10.40.0.71" cidr_netmask="26" iflabel="ma2" \
> op monitor interval="10s"
> primitive SERVICE-VIP ocf:heartbeat:IPaddr2 \
> params ip="10.40.0.72" cidr_netmask="24" iflabel="sla" \
> meta resource-stickiness="1" \
> op monitor interval="10s" timeout="60s" on-fail="restart"
> primitive SERVICE-res-mon-s1 ocf:heartbeat:service_res_check \
> params spanID="1" \
> meta resource-stickiness="1" \
> op monitor interval="9s" timeout="4s" on-fail="restart"
> primitive SERVICE-pgsql ocf:heartbeat:pgsql \
> params master_ip="10.40.0.70" slave_ip="10.40.0.72" node_list="serv1
> serv2" pgctl="/usr/bin/pg_ctl" psql="/usr/bin/psql"
> pgdata="/var/lib/pgsql/data/" start_opt="-p 5432" rep_mode="async"
> logfile="/var/log/service_ra_pgsql.log"
> primary_conninfo_opt="keepalives_idle=60 keepalives_interval=5
> keepalives_count=5" stop_escalate="0" \
> op start interval="0s" timeout="120s" on-fail="restart" \
> op monitor interval="7s" timeout="30s" on-fail="restart" \
> op monitor interval="2s" role="Master" timeout="30s" on-
> fail="restart" \
> op promote interval="0s" timeout="120s" on-fail="restart" \
> op demote interval="0s" timeout="30s" on-fail="stop" \
> op stop interval="0s" timeout="30s" on-fail="block" \
> op notify interval="0s" timeout="30s"
> primitive SERVICE-pingCheck ocf:pacemaker:ping \
> params host_list="10.40.0.99" name="default_ping_set"
> multiplier="100" \
> op start interval="0s" timeout="60s" on-fail="restart" \
> op monitor interval="2s" timeout="60s" on-fail="restart" \
> op stop interval="0s" timeout="60s" on-fail="ignore"
> primitive SERVICE-service ocf:heartbeat:service_service_ocf \
> op monitor interval="7s" timeout="30s" on-fail="restart"
> primitive SERVICE-tomcat ocf:heartbeat:tomcat \
> params java_home="/usr/java/default"
> catalina_home="/usr/share/tomcat6" statusurl="http://127.0.0.1:9081/admin"
> catalina_pid="/var/run/tomcat6.pid" tomcat_user="tomcat"
> script_log="/var/log/service_ra_tomcat.log" \
> op monitor interval="10s" timeout="40s" on-fail="restart" depth="0"
> \
> op start interval="0" timeout="40s"
> group master-group SERVICE-MIP1 SERVICE-MIP2 SERVICE-service SERVICE-tomcat
> ms msPostgresql SERVICE-pgsql \
> meta master-max="1" master-node-max="1" clone-max="2" clone-node-
> max="1" notify="true"
> clone clnPingd SERVICE-pingCheck
> location rsc_location-1 msPostgresql \
> rule $id="rsc_location-1-rule" -inf: not_defined default_ping_set or
> default_ping_set lt 100
> colocation rsc_colocation-1 inf: msPostgresql clnPingd
> colocation rsc_colocation-2 inf: master-group msPostgresql:Master
> colocation rsc_colocation-3 -inf: SERVICE-VIP msPostgresql:Master
> colocation rsc_colocation-4 -inf: SERVICE-res-mon-s1 msPostgresql:Master
> order rsc_order-1 0: clnPingd msPostgresql symmetrical=false
> order rsc_order-2 inf: msPostgresql:promote master-group:start
> symmetrical=false
> order rsc_order-3 0: msPostgresql:demote master-group:stop symmetrical=false
> property $id="cib-bootstrap-options" \
> dc-version="1.1.10-368c726" \
> cluster-infrastructure="corosync" \
> no-quorum-policy="ignore" \
> stonith-enabled="false" \
> crmd-transition-delay="0s" \
> last-lrm-refresh="1389346364"
> rsc_defaults $id="rsc-options" \
> resource-stickiness="INFINITY" \
> migration-threshold="1"
> #vim:set syntax=pcmk
>
>
>
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