I am developing a service for JMS messaging using IBM WMQ version 7.5 as Message oriented middleware. I am in a dilemma. The IBM specification says to use WebSphere MQ JMS API in JAVA EE environment. My sender and receivers will be in remote JBoss deployments. IBM provides a resource adapter to connect via JCA. This connection requires static administration of components such as Queue managers, queue channels, queue names.
Is JCA the best I can do ? Is there any other way where I can dynamically create the queues provided that I know other configuration details ? There will be multiple applications using this setup running on their own servers. If I use JCA, all have to make their own configurations. Can I make dynamic configurations ?
Typically within the application server environment resources would be created in some JNDI context. These would be Connection Factories and Destinations.
Depending on the app server, it may be possible to share this configuration across a network of individual servers. So typically there would be some set of static definitions.
However within say a servlet the MQConnectionFactory can be dynamically created.
In all cases the backing WMQ Resources do need to exist; though it is possible to send administrative command messages to WMQ to create queues and do other admin. The only exception is topics, accessing a topic string brings it into existence. Though this has default security properties that you might not want.
Related
We are designing a solution that will consume messages from IBM MQ using JMS. The plan is to use WAS Liberty, so JMS is the technology of choice. We will create Message-Drive beans that will listen for messages in MQ queues.
We are considering both WAS Liberty and OpenLiberty as well.
The trick here is that we must implement it with fail-over, so that if one of our server fail, the other will keep consuming messages from MQ automatically. Like in a ative/passive mechanism.
I'm aware that the MQ adapter needs to be installed as it is not provided out-of-the-box.
I have the following questions:
Does WAS Liberty messaging implementation supports fail-over? Meaning that if the ative message consumer node fails, the stand-by node will automatically migrate and start consuming messages from MQ? What about OpenLiberty?
How can I configure the message system to work that way? Can you point out to the documentation?
Or is this feature only provided by WebSphere?
There is no such functionality in WebSphere Liberty or Open Liberty yet. You can create RFE here https://www.ibm.com/developerworks/rfe/?PROD_ID=544 .
There are ways to do it manually, check these links:
JMS Activation spec on Liberty: “WAS_EndpointInitialState” full profile equivalent property?
Controlling the state of endpoints at runtime
Solution that you could do:
create a script/application that will monitor your servers and call that API to enable/disable endpoint in specific server
or use Dynamic cluster/ auto scaling feature of Liberty and divide you app to two clusters - one with MDBs, one without. And then define policy that MDBs cluster has 1 instance always available. So once the server dies it is automatically restarted somewhere in the cluster
or use Kubernetes/ICP platform in the same way - so deploying 2 versions of app, and defining different replicasets parameters.
We have a requirement for one standalone Java application that can push JMS message to a JMS queue configured on Weblogic, Websphere and JBoss application server.
Is there any generic JMS client library available, that we can use in our application for pushing the messages to any or all of these servers?
As we understand, there is a specific JMS client for each server (for e.g. wljmsclient.jar required for Weblogic target server, as we would need weblogic.jndi.WLInitialContextFactory to be available as Initial Context factory class, similarly for Websphere and JBoss). And we would like to avoid having 3 different JMS client libraries (1 each for server) in the same application.
However, the catch here is, destination server is not known during compilation time. Only during runtime, it will be known whether the given message is to be pushed to Weblogic, Websphere or JBoss server or all of them. Hence, there is a need for a deployed application to support all 3 servers during runtime.
Is there any alternative generic JMS client library?
You can develop your own client that supports the 3 servers.
Basically you need to have for your standalone application :
The different JMS provider jar on the classpath
For example a jms_config.properties file which stores the configuration for each server (initial context factory, etc.)
Then from a generic code you can build the InitialContext, JMS Queues, etc. depending on the target server.
I wrote a java client to connect to jms in websphere.
I was able to connect and produce and consume message.
Problem I am facing is when I do Session.createQueue(), websphere jms is not creating a new queue.
Please could some one throw some light on this issue...
Thanks in advance...
If you are working with WebSphere MQ as the messaging provider within WebSphere Application Server the queue will need to be created on the WebSphere MQ QueueManager first. This can be done either via the graphical WMQ Explorer or via the command line using the 'runmqsc' tool.
Information can be found for these via the WMQ InfoCentre - suggest doing a websearch for "WMQ Library" to get the latest link, currently though it is http://www-01.ibm.com/software/integration/wmq/library/index.html
Topics though don't need to be pre-created - though they can be if required. Various properties can be set different to the default.
If the Queue doesn't need to be permanent, for example as a temporary reply to then look into creating a temporary queue from the JMS Connection.
createQueue doesn't create a new queue. It simply creates a javax.jms.Queue object from a vendor specific identifier. javax.jms.Queue objects are just references to existing queues. Typically, you retrieve javax.jms.Queue objects from JNDI; createQueue is only useful in scenarios where using JNDI is not possible or not desirable.
Note: there is one exception to this, namely JMS providers that support autocreation of queues (I think ActiveMQ has such a feature).
Want to know how to create physical queue in JMS at run time.
when I search for this I got Creating JMS Queues at runtime
But when I read http://activemq.apache.org/how-do-i-create-new-destinations.html I come to know queue which mention in Creating JMS Queues at runtime is not creating any physical queue at server side.
Please correct me if I m wrong. If any one know to create physical queue at run time please replay.
Thanks in advance.
The creation of "normal" queues is not adressed by the JMS standard. Depending on what you want to do there are two approaches:
use temporary queues -> however they have many restrictions, most commonly they are used forrequest-reply scenarios
use the API of the JMS provider - however your solution will be depending on this specific provider then
The JMS standard only addresses sending and receiving data from objects like queues and topics. Creation of JMS artefacts is vendor specific and most often requires using:
1)specific vendor APIs (not JMS)
2)command/admin messages aimed at the JMS server (command agents on activemq)
3)JMX API
I have used JMX method, which is the most powerful, but also the most work.
JMX Method for activemq (version 5.0+)
a) JMS Server Setup
1) Enable JMX in activemq startup scripts and activemq.xml files
2) If you are authenticating to to the server, make sure your user has admin privileges setup in activemq.xml (see http://activemq.apache.org/security.html)
3)restart activemq server
b) Your Client Code
1) create an instance of org.apache.activemq.broker.jmx.BrokerViewMBean (you will need to connect with some JMX connectivity code which is a bit messy)
2) use its addQueue method. This will create a queue on the server
(The process is similar for hornetq but since you mentioned Activemq I have omitted hornetq details here.)
I have used this method myself and it works.
An alternative is to use Command Agents in Activemq, but I have no personal experience with these. These are special messages contain admin commands and may do what you want as well.
Currently I am working on a JMS application. But I use plain JMS API and Property file for configurations. My application is running in Weblogic and connects to MQ series server of my client.
Recently I got to know I can use Weblogic for JMS configurations.
Please explain.
What is "Foreign JMS provider"?
Is Weblogic also a JMS server or Foreign JMS provider or Both?
Weblogic provides the JMS Server features fully compliant with all JMS spec elements such as ConnectionFactory and Destinations. On this JMS Server you can connect and send messages to the client's Messaging Server via a configured Destination.
In addition using Weblogic as the JMS Server gives you lot many features such as Message Retry in case of failure, setting message quotas as well as enhanced monitoring of the JMS Server to track errors. The idea is to have more configuration driven settings for performance, deadlocks, tuning, filestore or database store etc.
A full list of such features is given at http://download.oracle.com/docs/cd/E12840_01/wls/docs103/jms/fund.html#wp1071787
A Foreign JMS Provider in Weblogic is the term used to define JMS implementations other than Weblogic JMS. An example is IBM MQ in your case.
Once the Foreign Provider is configured within Weblogic, for all practical purposes within the code - it can be called as if it was on local JNDI lookup. Weblogic will make the remote calls transparent to your code. This allows you to change your destination via configuration on the Weblogic console.
You will need a Messaging Bridge within Weblogic JMS Server to connect a source destination from which messages are received, and a target destination to which messages are sent.
Some essential reading on this is at: http://download.oracle.com/docs/cd/E12840_01/wls/docs103/jms_admin/advance_config.html#wp1075917
and an example of configuring IBM MQ as a Foreign Provider is at http://www.ibm.com/developerworks/websphere/library/techarticles/0604_kesavan/0604_kesavan.html#N1011D