缺少 docker 容器内进程的 PID

Question

I'm running a simple web application inside a docker container. When I look at the output of netstat, the PID/Program name is blank.

root@fasf343344423# sudo netstat -tulnp Active Internet connections (only servers) Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name tcp 0 0 0.0.0.0:5697 0.0.0.0:* LISTEN -
tcp 0 0 0.0.0.0:9090 0.0.0.0:* LISTEN -

I've seen the PID before on a different setup. So, I want to understand if this is because of a setup issue. Appreciate your help

Answer 1

I was able to resolve this with the following change:

1. Edit /etc/apparmor.d/docker file and add the following line

   ptrace peer=docker-default,

2. sudo service apparmor restart

Answer 2

As in my related question Which PID is using a PORT inside a k8s pod without net tools

The lack of POSIX Capability CAP_SYS_PTRACE avoids netstat to trace the inode to PID