JDK-8205992 : jhsdb cannot attach to Java processes running in Docker containers
Type:Bug
Component:core-svc
Sub-Component:tools
Affected Version:9,10,11,12
Priority:P4
Status:Resolved
Resolution:Fixed
Submitted:2018-06-28
Updated:2024-06-04
Resolved:2018-07-26
The Version table provides details related to the release that this issue/RFE will be addressed.
Unresolved : Release in which this issue/RFE will be addressed. Resolved: Release in which this issue/RFE has been resolved. Fixed : Release in which this issue/RFE has been fixed. The release containing this fix may be available for download as an Early Access Release or a General Availability Release.
jcmd supports container in JDK-8193710. However. jhsdb cannot do it.
JDK-8193710 has been changed to check PID namespace. jhsdb should also do so.
Comments
Fix request for 11u:
This patch makes jhsdb to attach to the process on container.
Original change cannot apply cleanly due to JDK-8202884.
The conflict is caused by header file inclusion in ps_proc.c, the others can be applied cleanly.
Review thread: https://mail.openjdk.java.net/pipermail/jdk-updates-dev/2020-December/004445.html
http://mail.openjdk.java.net/pipermail/serviceability-dev/2018-June/024288.html
I tried to attach jhsdb to java process in docker container from container host, but it couldn't.
jcmd supports PID namespace in JDK-8193710, but jhsdb hasn't yet.
SA gets LWP ID via thread stack and funcs in libthread_db.so, but they returns PIDs in container - they are different from host's PID. So I added the code to scan /proc/<PID>/task to get all LWP IDs and they are kept in a Map in LinuxDebuggerLocal.
Also SA_ALTROOT is set to /proc/<PID>/root if SA detects debuggee runs in container. It helps SA to parse binaries in container.