When running TestJcmd with podman under the root user I'm seeing a failure that looks like this:
----------System.err:(16/899)----------
[main-container-process] Error: keep-id is only supported in rootless mode
Failed to start a process (thread dump follows)
java.util.concurrent.TimeoutException
        at jdk.test.lib.process.ProcessTools.startProcess(ProcessTools.java:223)
        at jdk.test.lib.process.ProcessTools.startProcess(ProcessTools.java:143)
        at TestJcmd.startObservedContainer(TestJcmd.java:182)
        at TestJcmd.main(TestJcmd.java:77)
        at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103)
        at java.base/java.lang.reflect.Method.invoke(Method.java:578)
        at com.sun.javatest.regtest.agent.MainWrapper$MainThread.run(MainWrapper.java:125)
        at java.base/java.lang.Thread.run(Thread.java:1623)

JavaTest Message: Test threw exception: java.util.concurrent.TimeoutException
JavaTest Message: shutting down test

STATUS:Failed.`main' threw exception: java.util.concurrent.TimeoutException
----------rerun:(28/2230)*----------

The keep-id option should only be added when run as non-root.