Finding Docker container processes? (from host point of view)

Question

I am doing some tests on docker and containers and I was wondering:

Is there a method I can use to find all process associated with a docker container by its name or

Answer 1

the process run in a docker container is a child of a process named containerd-shim (in Docker v18.09.4)

• First figure out the process IDs of the containerd-shim processes.
• For each of them, find their child process.

---

pgrep containerd-shim

7105
7141
7248

To find the child process of parent process 7105:

pgrep -P 7105

7127

---

In the end you could get the list with:

for i in $(pgrep containerd-shim); do pgrep -P $i; done

7127
7166
7275