docker is process

docker ps

$ docker ps
CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS              PORTS               NAMES
9324a140f76b        node:8-alpine       "node"                   6 seconds ago       Up 5 seconds                            keen_hermann
6076ade2ab4f        nginx               "nginx -g 'daemon ..."   46 seconds ago      Up 45 seconds       80/tcp, 443/tcp     eager_bartik

ps axf.txt

 1118 ?        Ssl    0:01 /usr/bin/dockerd -H fd://
 1151 ?        Ssl    0:00  \_ docker-containerd -l unix:///var/run/docker/libcontainerd/docker-containerd.sock --metrics-interval=0 --start-time
 3161 ?        Sl     0:00      \_ docker-containerd-shim 6076ade2ab4f34176033b2a39aeb1e2228c3cfbb4189a83240259f89947b3b6d /var/run/docker/libcon
 3180 ?        Ss     0:00      |   \_ nginx: master process nginx -g daemon off;
 3212 ?        S      0:00      |       \_ nginx: worker process
 3408 ?        Sl     0:00      \_ docker-containerd-shim 9324a140f76b594cc004d18dedab597d73464ca8bf7f4a622892e86163234518 /var/run/docker/libcon
 3425 pts/5    Ssl+   0:00          \_ node