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https://issues.apache.org/jira/browse/AMQ-4122?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13584596#comment-13584596
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Gary Tully commented on AMQ-4122:
---------------------------------
@SouNayi - thanks for the slq log.
>From looking at
>https://issues.apache.org/jira/secure/attachment/12570319/mysql.log, it looks
>like a configuration problem.
node-h03-ap21 is obtaining a 5s lease that it renews every 10s. So there is a s
period when the lease is available to others.
It needs to obtain a 10 second lease and update it every 5 seconds. So that a
second (slave) broker always sees time > now when it attempts an update as part
of an acquire.
You need:
{code}
<jdbcPersistenceAdapter ... lockKeepAlivePeriod="5000">
..
<locker>
<lease-database-locker lockAcquireSleepInterval="10000"/>
</locker>
{code}
lockAcquireSleepInterval is the lease duration, lockKeepAlivePeriod is the
lease renew period. On a renew, the lease is extended by the
lockAcquireSleepInterval (lease duration). So a master is always
(lockAcquireSleepInterval - lockKeepAlivePeriod) ahead with its lease.
In short, ensure: lockAcquireSleepInterval > lockKeepAlivePeriod.
Can you verify this.
I think it may also makes sense to add lease related attributes to this locker.
leaseDuration, leaseRenewPeriod so that it is a little more intuitive and
obvious that the leaseDuration > leaseRenewPeriod
> Lease Database Locker failover broken
> -------------------------------------
>
> Key: AMQ-4122
> URL: https://issues.apache.org/jira/browse/AMQ-4122
> Project: ActiveMQ
> Issue Type: Bug
> Affects Versions: 5.7.0
> Environment: Java 7u9, SUSE 11, Mysql
> Reporter: st.h
> Assignee: Gary Tully
> Fix For: 5.8.0
>
> Attachments: activemq-kyle.xml, activemq.xml, activemq.xml,
> AMQ4122.patch, mysql.log
>
>
> We are using ActiveMQ 5.7.0 together with a mysql database and could not
> observe correct failover behavior with lease database locker.
> It seems that there is a race condition, which prevents the correct failover
> procedure.
> We noticed that when starting up two instances, both instance are becoming
> master.
> We did several test, including the following and could not observe intended
> functionality:
> - shutdown all instances
> - manipulate database lock that one node has lock and set expiry time in
> distance future
> - start up both instances. both instances are unable to acquire lock, as the
> lock hasn't expired, which should be correct behavior.
> - update the expiry time in database, so that the lock is expired.
> - first instance notices expired lock and becomes master
> - when second instance checks for lock, it also updates the database and
> becomes master.
> To my understanding the second instance should not be able to update the
> lock, as it is held by the first instance and should not be able to become
> master.
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