In a full WAS it is possible to stop and restart a JMS activation specification, either by using the administrative console or by using the J2CMessageEndpoint MBean. My question is if the J2CMessageEndpoint MBean will be available in Liberty Profile, making it possible to pause an activation specification?
If not, is there any other way that I can activate/deactivate the message endpoint in Liberty Profile?
There isn't a direct equivalent, but you can change the server xml so the activation specification binding no longer matches. When the server picks up the new configuration, which is dynamic by default, the binding won't match and the mdb will stop.
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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.
I want to make an application like JConsole. Is it possible? If yes, what are the changes need to done at JVM level? I am planning to use Spring-Boot. As per my knowledge, JMX is enabled by default. Do I need to configure anything extra in my Spring-Boot app in order to access the JMXBeans which are exposed by default?
Here I'm not trying to expose any MBean instead I'm trying to access those beans which are already exposed by JVM. How to achieve it?
JConsole is a JMX compliant monitoring and management application. The architecture is quite simple. It's a client-server architecture. Where the client is the Remote application (Example JConsole or the one that you want to build) and the server is the JMX Agent. In your case, you want to build your own client which is possible.
I want to make an application like JConsole. Is it possible?
Yes, it is possible.
If yes, what are the changes need to done at JVM level?
What do you mean by changes at JVM level? You are simply creating a client application that connects to the server (JMX Agent) using a certain protocol. Remote Method Invocation (RMI) is the protocol used by JConsole for the connection to the JMX Agent. If you want to use RMI for communication, you don't have to do anything on the server side. But if you want to use some other protocol for communication, you can define your own Protocol adapter.
As per my knowledge, JMX is enabled by default.
As of Java SE 6 it is. But you can only monitor it locally. For connection from a remote machine, you need to define an RMI port to start listening for incoming connections.
Here I'm not trying to expose any MBean instead I'm trying to access those beans which are already exposed by JVM. How to achieve it?
Please check out the example from this link - Mimicking Out-of-the-Box Management Using the JMX Remote API. It shows you how to create a simple client application that connects to a remote JMX agent and access the MBeans. This should guide you in the right direction.
I am trying to add new parameter from WSO2 admin console Transport Management -> JMS Listener screen (don't want to use axis2.xml as I want updates to be used by proxy services without re-starting servers - hope this is possible ?). While adding new parameter I am getting following error -
Error while initializing JMS listener
java.lang.String cannot be cast to org.apache.axiom.om.OMElement
Can you please advise what should be the format of parameter value. I am trying to add similar value as available under "default" or "myQueueConnectionFactory".
I tested your scenario and this seems to be a bug with ESB. Go to JMS Listener Configuration and click on Update without any change to the default parameter values. Even then the same error is thrown. So I have reported this issue at https://wso2.org/jira/browse/ESBJAVA-2412.
Unfortunately for now you will have to configure the parameters through axis2.xml until this issue is fixed. You can enable/disable the listeners through management console without any issue.
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.