Unable to use jstack or jmap when running Jenkins inside Docker container

Article ID:360037139692
1 minute readKnowledge base

Issue

Attempting to run jstack or jmap on the Jenkins process results in the following exception:

Error attaching to process: sun.jvm.hotspot.debugger.DebuggerException: Can't attach to the process: ptrace(PTRACE_ATTACH, ..) failed for my_pid: Operation not permitted

sun.jvm.hotspot.debugger.DebuggerException: sun.jvm.hotspot.debugger.DebuggerException: Can't attach to the process: ptrace(PTRACE_ATTACH, ..) failed for my_pid: Operation not permitted

                at sun.jvm.hotspot.debugger.linux.LinuxDebuggerLocal$LinuxDebuggerLocalWorkerThread.execute(LinuxDebuggerLocal.java:163)

                at sun.jvm.hotspot.debugger.linux.LinuxDebuggerLocal.attach(LinuxDebuggerLocal.java:278)

                at sun.jvm.hotspot.HotSpotAgent.attachDebugger(HotSpotAgent.java:671)

                at sun.jvm.hotspot.HotSpotAgent.setupDebuggerLinux(HotSpotAgent.java:611)

                at sun.jvm.hotspot.HotSpotAgent.setupDebugger(HotSpotAgent.java:337)

                at sun.jvm.hotspot.HotSpotAgent.go(HotSpotAgent.java:304)

                at sun.jvm.hotspot.HotSpotAgent.attach(HotSpotAgent.java:140)

                at sun.jvm.hotspot.tools.Tool.start(Tool.java:185)

                at sun.jvm.hotspot.tools.Tool.execute(Tool.java:118)

                at sun.jvm.hotspot.tools.JStack.main(JStack.java:92)

                at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

                at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)

                at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)

                at java.lang.reflect.Method.invoke(Method.java:498)

                at sun.tools.jstack.JStack.runJStackTool(JStack.java:140)

                at sun.tools.jstack.JStack.main(JStack.java:106)

Caused by: sun.jvm.hotspot.debugger.DebuggerException: Can't attach to the process: ptrace(PTRACE_ATTACH, ..) failed for my_pid: Operation not permitted

                at sun.jvm.hotspot.debugger.linux.LinuxDebuggerLocal.attach0(Native Method)

                at sun.jvm.hotspot.debugger.linux.LinuxDebuggerLocal.access$100(LinuxDebuggerLocal.java:62)

                at sun.jvm.hotspot.debugger.linux.LinuxDebuggerLocal$1AttachTask.doit(LinuxDebuggerLocal.java:269)

                at sun.jvm.hotspot.debugger.linux.LinuxDebuggerLocal$LinuxDebuggerLocalWorkerThread.run(LinuxDebuggerLocal.java:138)
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Environment

Resolution

You can try using jcmd as an alternative:

For threads:

jcmd [PID] Thread.print > [FILE]
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For heap:

jcmd [PID] GC.heap_dump [PATH]
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This article is part of our Knowledge Base and is provided for guidance-based purposes only. The solutions or workarounds described here are not officially supported by CloudBees and may not be applicable in all environments. Use at your own discretion, and test changes in a safe environment before applying them to production systems.