Zombie processes: from manually closing websocket?

[craigwalton-dsit]

Looking at ps aux in an agent container with 1 running command shows lots of zombied processes

root@agent-env-9oge6g5v-default-0:~# ps aux
USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
root         1  0.0  0.0  11028  3816 ?        Ss   17:37   0:00 tail -f /dev/null
root        87  0.0  0.0      0     0 ?        Z    17:39   0:00 [bash] <defunct>
root        88 72.0  0.0      0     0 ?        Z    17:39   4:36 [bash] <defunct>
root        89  0.0  0.0      0     0 ?        Z    17:39   0:00 [grep] <defunct>
root     37816  0.3  0.0  12720  6280 ?        Ss   17:43   0:00 bash
root     42980  0.0  0.0      0     0 ?        Z    17:44   0:00 [bash] <defunct>
root     42982  0.0  0.0      0     0 ?        Z    17:44   0:00 [bash] <defunct>
root     42985  0.0  0.0      0     0 ?        Z    17:44   0:00 [bash] <defunct>
root     42987  0.0  0.0      0     0 ?        Z    17:44   0:00 [timeout] <defunct>
root     42989  0.0  0.0      0     0 ?        Z    17:44   0:00 [bash] <defunct>
root     42990  0.0  0.0      0     0 ?        Z    17:44   0:00 [timeout] <defunct>
root     42992  0.0  0.0      0     0 ?        Z    17:44   0:00 [bash] <defunct>
root     42993  0.1  0.0      0     0 ?        Z    17:44   0:00 [timeout] <defunct>
root     42995  0.1  0.0      0     0 ?        Z    17:44   0:00 [bash] <defunct>
root     42997  0.0  0.0      0     0 ?        Z    17:44   0:00 [bash] <defunct>
root     42998  0.1  0.0      0     0 ?        Z    17:44   0:00 [timeout] <defunct>
root     43000  0.1  0.0      0     0 ?        Z    17:44   0:00 [timeout] <defunct>
root     43001  0.0  0.0      0     0 ?        Z    17:44   0:00 [bash] <defunct>
root     43002  0.0  0.0      0     0 ?        Z    17:44   0:00 [bash] <defunct>
root     43003  0.0  0.0      0     0 ?        Z    17:44   0:00 [timeout] <defunct>
root     43005  0.0  0.0      0     0 ?        Z    17:44   0:00 [timeout] <defunct>
root     43007  0.0  0.0      0     0 ?        Z    17:44   0:00 [bash] <defunct>
root     43008  0.0  0.0      0     0 ?        Z    17:44   0:00 [bash] <defunct>
root     43010  0.0  0.0  11000  3712 ?        Ss   17:44   0:00 timeout 300s /bin/sh
root     43011  0.0  0.0  10664  2828 ?        S    17:44   0:00 /bin/sh
root     43012  0.0  0.0  12456  6176 ?        S    17:44   0:00 bash -c finally() {     pwd > /tmp/bash_tool_last_dir     export -p  > /tmp/bash_tool_last_env } trap 'f
root     43013 96.1  0.0  15260  8084 ?        R    17:44   1:17 bash -c finally() {     pwd > /tmp/bash_tool_last_dir     export -p  > /tmp/bash_tool_last_env } trap 'f
root     43014  0.0  0.0  11968  4608 ?        S    17:44   0:00 grep is open
root     59414  176  0.0  16256  8540 ?        R    17:45   0:00 ps aux
root     59426 45.4  0.0  15260  8088 ?        R    17:45   0:00 [bash]
root     59433 85.7  0.0  15260  8088 ?        S    17:45   0:00 bash -c finally() {     pwd > /tmp/bash_tool_last_dir     export -p  > /tmp/bash_tool_last_env } trap 'f
root     59438  116  0.0  15260  8088 ?        S    17:45   0:00 bash -c finally() {     pwd > /tmp/bash_tool_last_dir     export -p  > /tmp/bash_tool_last_env } trap 'f
root     59440  150  0.0  15260  8088 ?        S    17:45   0:00 bash -c finally() {     pwd > /tmp/bash_tool_last_dir     export -p  > /tmp/bash_tool_last_env } trap 'f
root     59443  200  0.0  15260  8088 ?        S    17:45   0:00 bash -c finally() {     pwd > /tmp/bash_tool_last_dir     export -p  > /tmp/bash_tool_last_env } trap 'f
root     59444  550  0.0  11000  2984 ?        R    17:45   0:00 [timeout]
root     59445  600  0.0  15260  8088 ?        S    17:45   0:00 bash -c finally() {     pwd > /tmp/bash_tool_last_dir     export -p  > /tmp/bash_tool_last_env } trap 'f

Are these just sticking around because we manually closed the websocket upon seeing the sentinel value? I.e. maybe the stdout/stderr file descriptors remain open? Should we be closing it in some other way? Is this problematic?

Couldn't repro this reliably. It doesn't appear to be something which always happens.