Adjusting thread pools for container environments

Default thread pool values in Infinispan Server cloud.xml can make containers be killed if all of them are in use. The main defaults are:

• HotRod-hotrod-internal-ServerHandler: core=160 max=160
• remote-thread: core=25 max=25
• transport-thread: core=25 max=25
• async-thread: core=25 max=25
• jgroups: core=0 max=200
• jgroups-int: core=0 max=16
• stateTransferExecutor-thread: core=1 max=60
• add-listener-thread: core=0 max=10
• REST-rest-ServerHandler: core=1 max=1
• DefaultExecutorService: core=1 max=1
• notification-thread: core=1 max=1

The total number of core threads is 239, and if the system is under load, the threads alone can take ~239mb of native memory. That's before the heap and other parameters are counted. Our defaults are 0.5 CPU and 512mb.

This thread pools should be trimmed, since if used at full capacity, 0.5 CPU won't be able to do much with ~200+ threads.