1 Reply Latest reply on Oct 29, 2015 8:02 PM by jameslivingston

How to make sure application starts after the management interface

edykory Oct 29, 2015 6:42 AM

So, we have this very simple app (Reduced to simple), where we do the initialization in a @PostConstruct method of a @Startup @Singleton EJB bean.

The code is very simple, but it tries to read some resources throught the management interface

@Startup
@Singleton
public class StartupBean {
  @PostConstruct
  public void run() {
  try {
  final ModelNode addr = new ModelNode().add("subsystem", "security");
  final ModelNode mn = Operations.createReadResourceOperation(addr, true);

  final ModelControllerClient client = ModelControllerClient.Factory.create(InetAddress.getByName("127.0.0.1"), 9990);

  final ModelNode response;
  response = client.execute(mn);

  System.out.println(response.toJSONString(false));
  } catch (IOException e) {
  e.printStackTrace();
  }

  }
}

The problem is that if I just deploy (that is, if wildfly is already started), everything works as expected, but if I restart widfly, I receive

{
    "outcome" : "failed",
    "failure-description" : "WFLYCTL0379: System boot is in process; execution of remote management operations is not currently available"
}

and immediately after,

10:05:38,873 INFO [org.jboss.as] (Controller Boot Thread) WFLYSRV0060: Http management interface listening on http://127.0.0.1:9990/management

10:05:38,874 INFO [org.jboss.as] (Controller Boot Thread) WFLYSRV0051: Admin console listening on http://127.0.0.1:9990

Is there any way to configure my application to start after the management interface has been started?

1. Re: How to make sure application starts after the management interface

jameslivingston Oct 29, 2015 8:02 PM (in response to edykory)

You *really* shouldn't do that, there is a fairly major risk that you will cause a server deadlock.

If you perform a management operation, it could be queued behind any in-progress operations, such as performing a deployment. This means that JBoss may be waiting until the deployment finished, and hence waiting for your @PostConstruct method to complete. If you perform a blocking management operation from such a method, you will then make it wait until the operation completes and it can deadlock. In short, it is not safe to use management API from within any container-managed thread.

What precisely are you doing with the data it returns, and does the EJB absolutely require that information in the @PostConstruct method? You two options are to make it non-blocking (for example start a thread which runs the operation, and not make the method wait for completion) or get the data you need another way.
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