container support not enabled due to required cgroup subsystems not found

[Baesken, Matthias]

> Following subsystems are present in the docker container:
> # ls /sys/fs/cgroup/
> blkio  cpu  cpuacct  cpuacct,cpu  cpuset  devices  freezer  hugetlb
> memory  net_cls  net_prio  net_prio,net_cls  perf_event  pids  systemd
>
> As far as I understand, JVM is using only memory, cpu and cpuset
> subsystems

Hi,  in  jdk10  

"cpu,cpuacct"


Is checked  as well , see

http://hg.openjdk.java.net/jdk/jdk10/file/b09e56145e11/src/hotspot/os/linux/osContainer_linux.cpp

 ( but unfortunately  not  cpuacct,cpu  ).
This might cause  the message  :

> [0.001s][debug][os,container] Required cgroup subsystems not found


In  jdk11  both  "cpu,cpuacct"  and  "cpuacct,cpu"   are checked .
Jdk11  has also  a bit better  logging , so I think it would tell  you what  subsystem  is  not found .
Could you maybe   rerun  with jdk11  ?


Thanks, Matthias



> -----Original Message-----
> From: jdk-dev [mailto:jdk-dev-bounces at openjdk.java.net] On Behalf Of
> ashutosh mehra
> Sent: Donnerstag, 15. März 2018 11:52
> To: jdk-dev at openjdk.java.net
> Subject: container support not enabled due to required cgroup subsystems
> not found
> 
> When I run  jdk-10+46 build in a docker container, I don't see MaxHeapSize
> being adjusted based on container memory limit.
> 
> Command to run docker container with 2G memory, 2 CPUs:
> $ docker run -m2g --memory-swap=2g --cpus=2 -it --rm -v
> /home/ashu/data/builds/openjdk/jdk-10+46:/root/jdk-10 ubuntu:16.04
> 
> Once inside the container ran the following command:
> 
> # /root/jdk-10//bin/java -XX:+UnlockDiagnosticVMOptions
> -XX:+PrintFlagsFinal -version | grep MaxHeapSize
> 
> Output:
>    size_t MaxHeapSize                              = 2015363072
>                    {product} {ergonomic}
> openjdk version "10" 2018-03-20
> OpenJDK Runtime Environment 18.3 (build 10+46)
> OpenJDK 64-Bit Server VM 18.3 (build 10+46, mixed mode)
> 
> When I used -Xlog:os+container=trace option, I get following information:
> 
> # /root/jdk-10//bin/java "-Xlog:os+container=trace" -version
> 
> [0.001s][trace][os,container] OSContainer::init: Initializing Container
> Support
> [0.001s][debug][os,container] Required cgroup subsystems not found
> openjdk version "10" 2018-03-20
> OpenJDK Runtime Environment 18.3 (build 10+46)
> OpenJDK 64-Bit Server VM 18.3 (build 10+46, mixed mode)
> 
> Following subsystems are present in the docker container:
> # ls /sys/fs/cgroup/
> blkio  cpu  cpuacct  cpuacct,cpu  cpuset  devices  freezer  hugetlb
> memory  net_cls  net_prio  net_prio,net_cls  perf_event  pids  systemd
> 
> As far as I understand, JVM is using only memory, cpu and cpuset
> subsystems
> which are present in my system. Not sure why is it reporting "Required
> cgroup subsystems not found".
> 
> Any idea what could be wrong here? Are there other debug options to figure
> out what is going wrong?
> 
> Regards,
> Ashutosh Mehra