Re: [vcap-dev] Java OOM debugging

Daniel Mikusa


I've found using SSH tunnels can make debugging the JVM easier. I haven't
tried using Yourkit via a tunnel, but I suspect it would work. Maybe worth
a try. Some more details on setting up the tunnel here.


On Wed, Apr 29, 2015 at 10:53 AM, Head-Rapson, David <
David.Head-Rapson(a)> wrote:


I’m after some guidance on how to get profile Java apps in CF, in order to
get to the bottom of memory issues.

We have an app that’s crashing every few hours with OOM error, most likely
it’s a memory leak.

I’d like to profile the JVM and work out what’s eating memory, however
tools like yourkit require connectivity INTO the JVM server (i.e. the
warden container), either via host / port or via SSH.

Since warden containers cannot be connected to on ports other than for
HTTP and cannot be SSHd to, neither of these works for me.

I tried installed a standalone JDK onto the warden container, however as
soon as I ran ‘jmap’ to invoke the dump, warden cleaned up the container –
most likely for memory over-consumption.

I had previously found a hack in the Weblogic buildpack (
for modifying the start script which, when used with
–XX:HeapDumpOnOutOfMemoryError, should copy any heapdump files to a file
share somewhere. I have my own custom buildpack so I could use something

Has anyone got a better solution than this?

We would love to use newrelic / app dynamics for this however we’re not
allowed. And I’m not 100% certain they could help with this either.


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