带有JDBC MasterSlave的ActiveMQ计划程序故障转移

Question

I currently have a working two-broker JDBC MasterSlave configuration, and the next step for me is to implement a scheduler with failover. I've looked around and haven't seen any information about this, and was curious to see if this is possible or if I should try a different approach.

Currently, I have the two brokers using the same dataDirectory both within the broker tag and the JDBCPersistenceAdapter tag. However, within that data directory ActiveMQ creates two separate scheduler folders. I cannot seem to force it to use the same one, so failover with scheduling isn't working.

I've also tried the KahaDB approach with the same criteria, and that doesn't seem to work either.

Another option would be for the scheduler information to be pushed to the database (in this case, oracle) and be able to be picked up from there (not sure if possible).

Here is a basic overview of what I need:

1. Master and slave brokers up and running, using same dataDirectory (lets say, broker1 and broker2)
2. If I send a request to process messages through master at a certain time and master fails, slave should be able to pick up the scheduler information from master (this is where I'm stuck)
3. Slave should be processing these messages at the scheduled time

activemq.xml (relevant parts)

<broker xmlns="http://activemq.apache.org/schema/core" brokerName="b1" useJmx="true"
    persistent="true" schedulerSupport="true">

<!-- kahaDB persistenceAdapter -->

<persistenceAdapter>
    <kahaDB directory="{activemq.data}/kahadb" enableIndexWriteAsync="false" 
    ignoreMissingJournalfiles="true" checkForCorruptJournalFiles="true"
    checksumJournalFiles="true"/> 
</persistenceAdapter>

<!-- JDBC persistenceAdapter -->

<persistenceAdapter>
    <jdbcPersistenceAdapter dataDirectory="{activemq.data}" dataSource="#oracle-ds"/>
</persistenceAdapter>

Can someone possibly point me in the right direction? I'm fairly new to ActiveMQ. Thanks in advance!

Answer 1

If anyone is curious, adding the schedulerDirectory property to the broker tag seems to be working fine. So my broker tag in activemq.xml now looks like this:

<broker xmlns="http://activemq.apache.org/schema/core" brokerName="broker1"
    dataDirectory="{activemq.data}" useJmx="true" persistent="true"
    schedulerSupport="true" schedulerDirectory="{activemq.data}/broker1/scheduler"/>

Answer 2

You have probably figured out what you need to do to make this work, but for the sake of other folks like me who was/is looking for the answer. if you're trying to make failover work for scheduled messages with the default kahaDb store (as of v 5.13.2) and a shared file system, you will need to do the following:

1. Have a folder in the shared file system defined as the dataDirectory attribute in the broker tag. /shared/folder in the example below
2. Use the same brokerName for all nodes in that master/slave cluster. myBroker1 in the example below.

Example:

<broker xmlns="http://activemq.apache.org/schema/core" 
        brokerName="myBroker1" 
        dataDirectory="/shared/folder" 
        schedulerSupport="true">

Answer 3

我建议在ActiveMQ上支持问题https://issues.apache.org/jira/browse/AMQ-5238 ，因为即使您不使用计划的消息，也可以使用重新交付策略来解决计划程序问题。