I'm working on a project where I have several war files inside a tomcat 7 have to communicate with a single embedded activeMQ (5.5.1) broker inside the same Tomcat.
I'm wondering what was the best practice to manage this and how to start and stop the broker properly.
Actually I try tu use a global JNDI entry in server.xml and in each war gets my activemq connection with a lookup. The first connection to the broker implicitly starts it. But with this method I run into various problems like instance already existing or locks in data store.
Should I use instead an additional war which uses a BrokerFactory to start the broker explicitly? In this case how to make sure that this war executes first in Tomcat ? And how do I stop my broker and where?
Thanks for the help.
from the docs...
If you are using the VM transport and wish to explicitly configure an
Embedded Broker there is a chance that you could create the JMS
connections first before the broker starts up. Currently ActiveMQ will
auto-create a broker if you use the VM transport and there is not one
already configured. (In 5.2 it is possible to use the waitForStart and
create=false options for the connection uri)
So to work around this if you are using Spring you may wish to use the
depends-on attribute so that your JMS ConnectionFactory depends on the
embedded broker to avoid this happening. e.g.
see these pages for more information...
http://activemq.apache.org/vm-transport-reference.html
http://activemq.apache.org/how-do-i-embed-a-broker-inside-a-connection.html
http://activemq.apache.org/how-do-i-restart-embedded-broker.html
Related
One can create network connectors to exchange messages between two brokers with one of two ways:
Edit the conf/activemq.xml and adding network connectors inside <networkConnectors></networkConnectors>
Using the JMX API to add them programmatically via a BrokerViewMBean
When creating a network connector via JMX, this is not persistent, i.e. on broker restart it is not there anymore. Is this normal? Is there a way to create NCs using JMX that persist broker restart?
The connections created via JMX are temporary and are not written into the ActiveMQ configuration. You can view these as devops connections that can be used to test connectivity or to solve some messaging problems but for a permanent solution one needs to edit the ActiveMQ configuration file and add the desired connections there so that on each start they are recreated.
I have deployed two application in my mule standalone in which one application requires ActiveMQ up and running because I have applied reconnect-forever policy for connection.
but without starting ActiveMQ broker if i start mule.bat file it doesn't even deploy other applications which are not dependent on ActiveMQ.
What can be done to solve this issue so that only ActiveMQ dependent applications wait for the connection and other application start working.
Thank You.
Have you set blocking="false" in the reconnect?
I am using Glassfish 3.1.2, and I set up a cluster with one node and two instances.
I have an message driven bean in my application that subscribes to a topic, which I deployed to the cluster.
When I publish a message to the topic I want both instances to receive the message.
However, in practice I am finding that only one instance receives the message.
I believe I am running into a feature called "shared subscriptions"
http://docs.oracle.com/cd/E18930_01/html/821-2438/gjzpg.html#MQAGgjzpg
The feature (which is enabled by default) says that beans in the cluster with the same client id are shared, and are effectively only one subscription.
It says that by default the client id of an MDB is its name, which means that both my instances are using the same client id.
So other than completely disabling this feature, I would like to know if it is possible to setup an MDB so that each instance subscribes with a different client ID? This seems a bit tricky since both instances are using the same WAR file. I think you can set the client ID in an annotation, but I'm not sure if that can be changed at runtime...
I'm not sure why you would completly disable this feature. In the link you provided, it states clearly that you configure this per ActivationSpec/MDB. So as far as I understand it, it would affect only the MDB you have at hand.
For an MDB, set the ActivationSpec property useSharedSubscriptionInClusteredContainer to false. Do this in exactly
the same way as with other ActivationSpec properties, using
annotations in the MDB itself or in the deployment descriptor
ejb-jar.xml or glassfish-ejb-jar.xml.
But you can of course set the client ID on a connection dynamically during runtime. Please note that you probably would have to handle the JMS connection yourself a bit more than relying on the features managed by the container.
http://docs.oracle.com/javaee/6/api/javax/jms/Connection.html#setClientID(java.lang.String)
I am confused about the function of Apache ActiveMQ.
I downloaded ActiveMQ from this link.
So I use it this way (environment: Windows 7): I start the bin/activemq.bat, then it works.
My question is: Does this mean I start a server on my machine? When I initialize the ActiveMQConnectionFactory, the broker URL is tcp://localhost:61616. But what if I want my machine to serve as a server and another machine to connect to my server?
Yes, you can use the primary box as a server and have consumers/subscribers running on other boxes (which will need to connect to the server - you will need to specify the server hostname & port for the connection to be established) - once in place, the messages on the server (topic or queue) can be consumed by the clients.
If you one have one producer and one consumer, you can look into using queues - if you have more than one consumer/subscriber, you can look into setting up a topic to which the consumers will subscribe to. Messages need to be inserted to the topic/queue as needed.
You can specify the server information in your code or preferably in the config file.
For reference to topologies:
http://activemq.apache.org/topologies.html
Also, you can choose to persist your messages or not based on your use case. Kaha DB is the preferred route (specially if performance is of concern).
Useful examples:
http://sujitpal.blogspot.com/2007/12/jms-patterns-with-activemq.html
http://vvratha.blogspot.com/2012/05/java-client-to-sendreceive-messages-for.html
Hope it helps.
Apache ActiveMQ ™ is the most popular and powerful open source messaging and Integration Patterns server
& it act like a third party server.
Apache ActiveMQ is fast, supports many Cross Language Clients and Protocols, comes with easy to use Enterprise Integration Patterns and many advanced features while fully supporting JMS 1.1 and J2EE 1.4. Apache ActiveMQ is released under the Apache 2.0 License.
ActiveMQ have the capabilities to send 100 MB single message framework and maintain 1000 concurrent connection simultaneously , for the further information you can check activemq.xml in your documentation.
Further Info at here about the ActiveMQ
I have a WebLogic cluster on which I've deployed numerous topics and applications that use them. My applications uniformly show themselves in a Warning status. Looking at Monitoring on the deployment, I see the MDB application connects to Server #1, but on server #2 it shows this:
MDB application appName is NOT connected to messaging system.
My JMS Server is targetted to a migratable target, which is in turn targetted to the #1 server and has a cluster identified. And messages sent to either server all flow as expected. I just don't know why these deployments show in a Warning state.
WebLogic 11g
This can be avoided by using the parameter below
<start-mdbs-with-application>false</start-mdbs-with-application>
In the weblogic-application.xml, Setting start-mdbs-with-application to false forces MDBs to defer starting until after the server instance opens its listen port, near the end of the server boot up process.
If you want to perform startup tasks after JMS and JDBC services are available, but before applications and modules have been activated, you can select the Run Before Application Deployments option in the Administration Console (or set the StartupClassMBean’s LoadBeforeAppActivation attribute to “true”).
If you want to perform startup tasks before JMS and JDBC services are available, you can select the Run Before Application Activations option in the Administration Console (or set the StartupClassMBean’s LoadBeforeAppDeployments attribute to “true”).
Refer :http://docs.oracle.com/cd/E13222_01/wls/docs81/ejb/message_beans.html
this is applicable for the versions till 12c and later
I don't like unanswered questions, so I'm going to answer this one.
The problem is resolved, though I was not involved in its resolution. At present the problem only exists for the length of time it takes the JMS subsystem to fully initialize. During that period (with many queues, it can take a while) the JNDI system throws errors and the apps are truly in warning state. Once the JMS is fully initialized, everything goes green.
My belief is that someone corrected something in the JMS Server / Cluster config. I'll never know what it was.