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  1. JDK
  2. JDK-8250627

Use -XX:+/-UseContainerSupport for enabling/disabling Java container metrics

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    • Resolved In Build:
      b09
    • CPU:
      generic
    • OS:
      linux

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        Description

        For hotspot one can disable container detection with a simple switch:

        $ java -XX:-UseContainerSupport -Xlog:os+container=trace -version
        [0.000s][trace][os,container] OSContainer::init: Initializing Container Support
        [0.000s][trace][os,container] Container Support not enabled
        openjdk version "15-internal" 2020-09-15
        OpenJDK Runtime Environment (build 15-internal+0-adhoc.sgehwolf.openjdk-head-2)
        OpenJDK 64-Bit Server VM (build 15-internal+0-adhoc.sgehwolf.openjdk-head-2, mixed mode, sharing)

        The same cannot be achieved with the Java code,
        jdk.internal.platform.Metrics.java and friends in the JDK. At the time
        Metrics were added the only consumer of them was the Java Launcher via
        -XshowSettings:system. This has changed with JDK-8226575:
        OperatingSystemMXBean should be made container aware.

        It is known that in certain cases the container detection code will
        detect for a system to be supposedly in a container where it actually
        isn't:
        https://bugs.openjdk.java.net/browse/JDK-8227006?focusedCommentId=14275604&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-14275604

        For hotspot there is a flag, to turn auto-detection off for exactly the
        case when heuristics are wrong: -XX:-UseContainerSupport. However, this
        flag has no effect on the Java metrics code. There is a risk that on
        some systems the auto-detection will be wrong and might cause
        regressions.

        I propose to make the Java metrics code adhere to -XX:+/-
        UseContainerSupport flag.

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                • Assignee:
                  sgehwolf Severin Gehwolf
                  Reporter:
                  sgehwolf Severin Gehwolf
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                    Updated:
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