docker container 내에 ps 명령이 없는 경우 docker 명령을 통해 프로세스 정보를 확인할 수 있습니다.
docker top
$ docker top --help
Usage: docker top CONTAINER [ps OPTIONS]
Display the running processes of a container
$ docker top container1
UID PID PPID C STIME TTY TIME CMD
systemd+ 5447 5427 0 10월02 ? 00:00:07 postgres
systemd+ 5506 5447 0 10월02 ? 00:00:00 postgres: checkpointer
systemd+ 5507 5447 0 10월02 ? 00:00:00 postgres: background writer
systemd+ 5508 5447 0 10월02 ? 00:00:00 postgres: walwriter
systemd+ 5509 5447 0 10월02 ? 00:00:02 postgres: autovacuum launcher
systemd+ 5510 5447 0 10월02 ? 00:00:07 postgres: stats collector
systemd+ 5511 5447 0 10월02 ? 00:00:00 postgres: logical replication launcher
systemd+ 71037 5447 0 01:01 ? 00:00:00 postgres: postgres devpg 172.17.0.1(44588) idle
systemd+ 71054 5447 0 01:02 ? 00:00:00 postgres: postgres devpg 172.17.0.1(2274) idle
systemd+ 71062 5447 0 01:02 ? 00:00:00 postgres: postgres devpg 172.17.0.1(57654) idle
systemd+ 71079 5447 0 01:03 ? 00:00:00 postgres: postgres devpg 172.17.0.1(57554) idle
systemd+ 71085 5447 0 01:03 ? 00:00:00 postgres: postgres devpg 172.17.0.1(1990) idle
systemd+ 71103 5447 0 01:04 ? 00:00:00 postgres: postgres devpg 172.17.0.1(12182) idle
systemd+ 71153 5447 0 01:06 ? 00:00:00 postgres: postgres devpg 172.17.0.1(41064) idle
systemd+ 71161 5447 0 01:07 ? 00:00:00 postgres: postgres devpg 172.17.0.1(24732) idle
systemd+ 71166 5447 0 01:07 ? 00:00:00 postgres: postgres devpg 172.17.0.1(51552) idle
systemd+ 75606 5447 0 01:27 ? 00:00:00 postgres: postgres devpg 172.17.0.1(39372) idle