Re: Newbie configuration questions

[Adrian Co]

Also, network connectors at the moment are uni-directional, which means 
that if brokerA has a network connector that connects to brokerB, 
brokerA can send messages to brokerB, but brokerB cannot send messages 
to brokerA. See https://issues.apache.org/activemq/browse/AMQ-920. In 
your config below, the embedded brokers can send messages to the remote 
broker, but the remote broker cannot send messages to the embedded brokers.

Adrian Co wrote:
ktrue wrote:
Hi guys,

Adrian Co wrote:
 
For me, one of the key use of embedding brokers in the client, is 
that clients can continue processing stuff even when the remote 
broker is down. AFAIK, using the failover protocol, will block the 
sending of a message until the client is able reconnect to the 
broker. If you use an embedded broker, messages will be persisted 
automatically, and be sent when the remote broker comes online 
again, and the actual producer need not worry about it. I don't 
think theres not much use for a failover:vm://client as using an 
embedded broker assumes that if a broker goes down, the client in 
essence is also down.
        

Adrian, I wanted to share with you the previous "network of brokers"
configuration that was used in our product that didn't seem to implement
failover as expected.
Previously the server defined a broker thusly:

    <beans xmlns="http://activemq.org/config/1.0";>
        <broker brokerName="adminserver" useJmx="false"
useShutdownHook="false">
            <transportConnectors>
                <transportConnector name="default"
uri="tcp://localhost:61616"/>
            </transportConnectors>
            <networkConnectors>
                <networkConnector name="default"
uri="static:tcp://localhost:61616"/>
            </networkConnectors>
        </broker>
    </beans>
  
I find this part odd. You have a network connector to 
tcp://localhost:61616, and you're exposing the same transport 
connector. Seems that you're connecting to yourself? I'm not sure if 
this is the actual problem, its just odd.
The previous configuration of the clients included an embedded broker as
well:

    <bean id="jmsBroker"
      class="org.apache.activemq.broker.BrokerService"
      init-method="start"
      destroy-method="stop">
        <property name="brokerName" value="cruncheragent"/>
        <property name="useJmx" value="false"/>
        <property name="useShutdownHook" value="false"/>
        <property name="networkConnectorURIs">
            <list>
                <value>static:(failover:(tcp://localhost:61616))</value>
            </list>
        </property>
    </bean>
    <bean id="jmsConnectionFactory"
      class="org.apache.activemq.pool.PooledConnectionFactory"
      init-method="start"
      destroy-method="stop">
        <property name="connectionFactory">
            <bean class="org.apache.activemq.ActiveMQConnectionFactory">
                <property name="brokerURL" value="vm://cruncheragent"/>
            </bean>
        </property>
    </bean>
However, what happened when I stopped the server (broker 
"adminserver"), I
get this message in the client:

    2006-11-17 16:20:41,588 WARN
[org.apache.activemq.network.DemandForwardingBridge] - Unexpected 
                                                          remote 
command:
ShutdownInfo {commandId = 52, responseRequired = false}
    2006-11-17 16:20:41,590 WARN
[org.apache.activemq.network.DemandForwardingBridge] - Outbound 
                                                          transport to
adminserver interrupted ...

However, once I start the server, I never see any further messages 
about the
matter and the clients don't appear to reconnect (i.e. I never see 
messages
on the server from the clients again). HOWEVER, if I don't use an 
embedded
broker on the client and use failover:tcp://localhost:61616, the 
messages
are sent to the server when it is once again available.

In short, it seems like sticking an embedded broker in between the
ConnectionFactory and the server seems to break failover.

Additionally, you asked:

    Could be if you are connecting to other JMS brokers aside from 
AMQ, but
if you are networking
    ActiveMQ brokers only, I don't think so.

Just to rule that out, no, I'm only connecting to ActiveMQ servers.

Adrian and Gabriel: thanks for your input and help so far.

Thanks!
Kirk