HA-JNDI and twiddle

[jerrygauth]

JBAS-3138 reports that when HA-JNDI is used with twiddle to return attributes for an mbean deployed on one server in a cluster, the operation frequently fails. For example, the following works sporadically.

twiddle --server=jnp://localhost:1100 get "mybean:service=myservice" MyAttribute

I've confirmed the report on JBossAS 4 and 5. Upon investigation, I'm not sure that this is a bug as it seems like twiddle can't use HA-JNDI in this manner.

Because twiddle is running remotely and MBeans can't be directly looked up via JNDI, twiddle (or some other software in the stack) does a JNDI lookup on jmx/invoker/RMIAdaptor. It then uses this object to access the desired mbean.

When the user performs this operation using a HA-JNDI server, the operation is routed to one of the HA-JNDI servers based upon the load balancing policy in use. This might not be the server the user specified in the url and it might not be the server where the mbean was deployed.

If the lookup returns the adapter from the server where the mbean was deployed, it successfully accesses the mbean and returns the expected result. If the lookup returns the adapter from a different HA-JNDI server, the adapter can't locate the mbean so the operation fails.

This doesn't seem to be an HA-JNDI issue and may not be a bug at all, depending on how twiddle is supposed to work with HA-JNDI servers.

Thoughts?

[brian.stansberry]

Thanks for looking into this :). This seems like a WON'T_FIX to me, unless someone jumps in and says twiddle was really intended to support this use case.

[starksm64]

I wouldn't say its a won't fix, but its well outside of the scope of twiddle and the single node jmx-invoker. Even if we had a cluster aware binding of the jmx-invoker or jsr160 jmx remoting layer, twiddle would have to be rewritten to query all servers, a random server, the correlator, etc based on some behavior option.

[jerrygauth]

I've updated this issue with Scott's comments and marked it as unassigned.

[brian.stansberry]

Changed to an unscheduled feature request. If you are interested in this feature, please vote for the JIRA.