GRAYLOG_SERVER_JAVA_OPTS default settings about graylog-docker

[runningman84]

Does the current docker image respect the cgroup settings and does not need any Xms setting in JAVA_OPTS?

[vaizki]

I am running 3.0.2 and can see the JVM started with these flags:

-XX:+UnlockExperimentalVMOptions 
-XX:+UseCGroupMemoryLimitForHeap
-XX:NewRatio=1 
-XX:MaxMetaspaceSize=256m 
-server 
-XX:+ResizeTLAB 
-XX:+UseConcMarkSweepGC 
-XX:+CMSConcurrentMTEnabled 
-XX:+CMSClassUnloadingEnabled 
-XX:+UseParNewGC 
-XX:-OmitStackTraceInFastThrow -jar 
-Dlog4j.configurationFile=/usr/share/graylog/data/config/log4j2.xml 
-Djava.library.path=/usr/share/graylog/lib/sigar/ 
-Dgraylog2.installation_source=docker

If I set the memory limit for the container to 2GB, I get a max heap size of 486.4MB so it is respecting the container cgroup limits but being very wasteful. The machine has 64GB of RAM.

With Java 10, the JVM by default respects container limits by default and has much nicer tunables... wink wink.

[malcyon]

Just doing some testing, it seems like it does respect the cgroup settings. If you limit the amount of RAM available to the container, the JVM will start with less RAM. But if you don't limit it, it uses what the underlying OS has available.