Can you please explain me what is the meaning of deploy term on Application Server (JBoss for example) ? Does it mean class loading of war/ear to JVM ?
If so , does war/ear is being undeploy automatically when server is stopped ?
Does war with deployed marker is deploy also when server is stop ?
When you deploy an app, the application servers allocates the resources needed for that app to work.. Like you say, it means loading the app's classes, but also making database connections, etc.
When you stop the server, all apps are undeployed (because you are terminating the jvm). Shutting down the server releases all the resources that were allocated.
Once the app server is down, the jvm no longer exists, so no app will be deployed..
Related
IBM MobileFirst 7.1 is not auto recovering after a network failure / lost of connection even though all services/connections are back to normal.
We have a clustered / farm setup with 2 web and app servers (Tomcat). Both app servers are able to serve incoming transactions. We have this incident where-in there is a network failure/lost connection and during that time, all transactions are pointing to 1 app server. Although all connections went back to normal, this 1 app server still unable to connect to the configuration DB. What we did is turn-off this failure server and try the app which is now pointing to the other app server and the app works. We tried to restart the failure app server, test the app and is now accepting transactions. The question is, why it does not auto recover and Tomcat service needs to be restarted? Is MobileFirst 7.1 designed/built in such behavior (not auto recover)?
The expectation is, it should auto recover.
Please help and advise what can be checked/adjusted.
Thanks in advance.
Best regards,
Jonathan
The default DB configuration (datasource configuration) provided with MFP is not designed to auto recover when there is a DB connectivity issue. You
should be able to configure the MFP for auto-reconnect by providing correct data source configuration. See an article on how this is done for different app servers : https://www.techpaste.com/2016/04/jndi-autoreconnect-java-application-servers/
I noticed that both options are available while running Jboss, and they both recompile the project (I noticed 'make' running with both). I did see this question, the accepted answer made sense, but I wasn't sure what hot-swapping means. What is a possible example of a change which could be registered without needing to restart the server?
Your question needs more details to answer completely, but here are some basic concepts:
Hot-swapping is simply replacing the files of your project into the deployment folder of the application server (unpackaged, i.e. not the .war/.ear but all separate files). It is usually faster because the change are immediately visible in the web-application. But it is not always possible/supported by application servers, and often if you hot-swap .jar files the application server doesn't pick it up or end up confused.
Restarting JBoss will stop all existing services ( EJBs, Pooling, Queues, Messaging...) and restart them. It is almost the cleanest way to run your application (the cleanest would be un-deploy, restart and deploy)
Redeploy means your application and its services are first removed from JBoss, but other services setup at server level (Messaging, Pools, JMX,... depends on your actual settings) are still deployed. Then the application is deployed (copied from your dev folder or .WAR/.EAR to JBoss webapp)
Typically, you would hot-swap (eventually manually) .(x)html/.jsp/.jsf/images/.js/.css safely as JBoss doesn't need to process them.
Changing code in java classes deployed as .class in a WEB-INF/classes can often be hot-swapped.
Changing code in java files deployed as .jar will almost always need at least redeployment. Some OSGi enabled application server properly configured are more flexible in hot-swapping a complete application (I know Glassfish does but I don't know what specific setting is needed)
Finally, in development, sometimes the multiple redeployments lead to memory leak or unstable application server (often you'll get a OutOfMemory exception in the logs) then you need to cleanup (undeploy, stop, start then deploy)
When running jboss 7.1 as a windows service (or not), it occasionally takes more than one try to successfully deploy a war file. This is not a problem when starting jboss manually since restarts are easy. However, when jboss runs as a windows service and it is restarted automatically (due to a windows patch), jboss itself may launch, but the war may not.
Is there any way to cause jboss to retry deploying the war after it fails the first time - for example, by changing a setting in standalone.xml?
There are to ways to fix your problem.
1) go to standalone.xml (or whatever configuration you are running), find deployment-scanner and add/modify attribute deployment-timeout in seconds
2) Deploy your application as managed deployment, you can do that if you deploy trough admin console or via cli with deploy command. This way deployment will then be "managed" and will always be deployed and wont be using deployment scanner and its timeouts.
I recommend you to use deploy as managed deployment as deployment scanner is not really recommend to be used in production environments as it adds additional IO load on filesystem.
It is great for development / testing scenarios but should be avoided in production if possible.
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.
When I start a Weblogic instance with a deployed application, the deployment is sometimes left in prepared state, not in active state. I have to go to Weblogic Console and start the deployment manually, which is quite slow and annoying repetetive work. Since this is done on a development machine — sometimes 50 times a day, — there are no security implication as the server is only visible on the local network. Is there some way to have it always start the deployment active?
Note that I'm not redeploying the application, I instead have it "constantly deployed" and stop/start the Weblogic instance using the scripts in bin directory.
If you are running weblogic in development mode, you can use the autodeploy folder for your app. See details here: http://download.oracle.com/docs/cd/E11035_01/wls100/deployment/autodeploy.html#wp1021620
Think this should solve your problem