root@server:~/docker# docker container ps --filter "ancestor=example/echo"
CONTAINER ID        IMAGE                 COMMAND                  CREATED             STATUS              PORTS                    NAMES
0371d5eb3d1e        example/echo:latest   "go run /echo/main.go"   9 minutes ago       Up 9 minutes        0.0.0.0:9001->8000/tcp   echo2
e2c45c8b92f9        example/echo:latest   "go run /echo/main.go"   10 minutes ago      Up 10 minutes       0.0.0.0:9000->8000/tcp   echo1