[Pacemaker] [SOLVED] RE: Slave does not start after failover: Mysql circular replication and master-slave resources
Attila Megyeri
amegyeri at minerva-soft.com
Sat Dec 17 09:51:50 UTC 2011
Hi all,
For anyone interested.
I finally made the mysql replication work. For some strange reason there were no [mysql] log entries at all neither in corosync.log nor in the syslog. After a couple of corosync restarts (?!) [mysql] RA debug/error entries started to show up.
The issue was that the slave could not apply the binary logs due to some duplicate errors. I am not sure how this could happen, but the solution was to ignore the duplicate errors on the slaves, by adding the following line to the my.conf:
slave-skip-errors = 1062
I hope this helps to some of you guys as well.
P.S. Did anyone else notice missing mysql debug/info/error entries in corosync log as well?
Cheers,
Attila
-----Original Message-----
From: Attila Megyeri [mailto:amegyeri at minerva-soft.com]
Sent: 2011. december 16. 12:39
To: The Pacemaker cluster resource manager
Subject: Re: [Pacemaker] Slave does not start after failover: Mysql circular replication and master-slave resources
Hi Andreas,
The slave lag cannot be high, as the slave was restarted within 1-2 mins and there are no active users on the system yet.
I did not find anything at all in the logs.
I will doublecheck if the RA is the latest.
Thanks,
Attila
-----Original Message-----
From: Andreas Kurz [mailto:andreas at hastexo.com]
Sent: 2011. december 16. 1:50
To: pacemaker at oss.clusterlabs.org
Subject: Re: [Pacemaker] Slave does not start after failover: Mysql circular replication and master-slave resources
Hello Attila,
... see below ...
On 12/15/2011 02:42 PM, Attila Megyeri wrote:
> Hi All,
>
>
>
> Some time ago I exchanged a couple of posts with you here regarding
> Mysql active-active HA.
>
> The best solution I found so far was the Mysql multi-master
> replication, also referred to as circular replication.
>
>
>
> Basically I set up two nodes, both were capable of the master role,
> and the changes were immediately propagated to the other node.
>
>
>
> But still I wanted to have a M/S approach, to have a RW master and a
> RO slave - mainly because I prefer to have a signle master VIP where
> my apps can connect to.
>
>
>
> (In the first approach I configured a two node clone, and the master
> IP was always bound to one of the nodes)
>
>
>
> I applied the following configuration:
>
>
>
> node db1 \
>
> attributes IP="10.100.1.31" \
>
> attributes standby="off"
> db2-log-file-db-mysql="mysql-bin.000021" db2-log-pos-db-mysql="40730"
>
> node db2 \
>
> attributes IP="10.100.1.32" \
>
> attributes standby="off"
>
> primitive db-ip-master ocf:heartbeat:IPaddr2 \
>
> params lvs_support="true" ip="10.100.1.30" cidr_netmask="8"
> broadcast="10.255.255.255" \
>
> op monitor interval="20s" timeout="20s" \
>
> meta target-role="Started"
>
> primitive db-mysql ocf:heartbeat:mysql \
>
> params binary="/usr/bin/mysqld_safe" config="/etc/mysql/my.cnf"
> datadir="/var/lib/mysql" user="mysql" pid="/var/run/mysqld/mysqld.pid"
> socket="/var/run/mysqld/mysqld.sock" test_passwd="XXXXX"
>
> test_table="replicatest.connectioncheck" test_user="slave_user"
> replication_user="slave_user" replication_passwd="XXXXX"
> additional_parameters="--skip-slave-start" \
>
> op start interval="0" timeout="120s" \
>
> op stop interval="0" timeout="120s" \
>
> op monitor interval="30" timeout="30s" OCF_CHECK_LEVEL="1" \
>
> op promote interval="0" timeout="120" \
>
> op demote interval="0" timeout="120"
>
> ms db-ms-mysql db-mysql \
>
> meta notify="true" master-max="1" clone-max="2"
> target-role="Started"
>
> colocation db-ip-with-master inf: db-ip-master db-ms-mysql:Master
>
> property $id="cib-bootstrap-options" \
>
> dc-version="1.1.5-01e86afaaa6d4a8c4836f68df80ababd6ca3902f" \
>
> cluster-infrastructure="openais" \
>
> expected-quorum-votes="2" \
>
> stonith-enabled="false" \
>
> no-quorum-policy="ignore"
>
> rsc_defaults $id="rsc-options" \
>
> resource-stickiness="0"
>
>
>
>
>
> The setup works in the basic conditions:
>
> * After the "first" startup, nodes start up as slaves, and
> shortly after, one of them is promoted to master.
>
> * Updates to the master are replicated properly to the slave.
>
> * Slave accepts updates, which is Wrong, but I can live with
> this - I will allow connect to the Master VIP only.
>
> * If I stop the slave for some time, and re-start it, it will
> catch up with the master shortly and get into sync.
>
>
>
> I have, however a serious issue:
>
> * If I stop the current master, the slave is promoted, accepts
> RW queries, the Master IP is bound to it - ALL fine.
>
> * BUT - when I want to bring the other node online, it simply
> shows: Stopped (not installed)
>
>
>
> Online: [ db1 db2 ]
>
>
>
> db-ip-master (ocf::heartbeat:IPaddr2): Started db1
>
> Master/Slave Set: db-ms-mysql [db-mysql]
>
> Masters: [ db1 ]
>
> Stopped: [ db-mysql:1 ]
>
>
>
> Node Attributes:
>
> * Node db1:
>
> + IP : 10.100.1.31
>
> + db2-log-file-db-mysql : mysql-bin.000021
>
> + db2-log-pos-db-mysql : 40730
>
> + master-db-mysql:0 : 3601
>
> * Node db2:
>
> + IP : 10.100.1.32
>
>
>
> Failed actions:
>
> db-mysql:0_monitor_30000 (node=db2, call=58, rc=5, status=complete):
> not installed
>
Looking at the RA (latest from git) I'd say the problem is somewhere in the check_slave() function. Either the check for replication errors or for a too high slave lag ... though on both errors you should see the log. entries.
Regards,
Andreas
--
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>
>
>
>
> I checked the logs, and could not find a reason why the slave at db2
> is not started.
>
> Any IDEA Anyone ?
>
>
>
>
>
> Thanks,
>
> Attila
>
>
>
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