Make JVM respect CPU and RAM limits

On startup JVM tries to detect the number of available CPU cores and the amount of RAM to adjust its internal parameters (like the number of garbage collector threads to spawn) accordingly. When container is run with limited CPU/RAM, standard system API, used by JVM for probing, will return host-wide values. This can cause excessive CPU usage and memory allocation errors with older versions of JVM.

Inside Linux containers, recent versions of OpenJDK 8 (8u131 or newer and 9) can correctly detect container-limited number of CPU cores by default. To enable the detection of container-limited amount of RAM the following options can be used:

$ java -XX:+UnlockExperimentalVMOptions -XX:+UseCGroupMemoryLimitForHeap ...