Re: [wildfly-dev] Gathering diagnostic data

Hi, I do support for JBoss at RH, especially lower level components like the JVM and core server, and I've come to realise that we don't have particularly good mechanisms for gathering diagnostic data. Obviously there is logging, but for a number of problems it isn't enough. There is also the JDR subsystem, but that has the serious limitation that the server instance(s) have to be working correctly to use it. One piece of data that I think can be useful for a common set of problems are thread dumps. For standalone instances Oracle/OpenJDK's 'jstack' tool is useful, but for domain mode you need to manually go to each machine and find the correct process ID to use it. Something that could potentially be useful is to be able to tell Host Controllers to take a thread dump from the servers it manages (or all of them), using the same Attach/SA APIs as jstack. A feature to allow HC-based extensions as mentioned in the thread about the RHQ agent could be useful for implementing this too. Right now, I believe it would need to be added to the HC code directly. Is this something that might be possible or a good idea to do? I have some ideas about other things that may be useful, like per-thread CPU usage which RH support currently uses a pile of shell scripts for, but starting with one thing may be simpler.