Update gitlab docker image documentation

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What does this MR do?

This MR updates the gitlab docker image documentation. This was fixed in this issue and MR a few years ago, but somehow reverted.

• Issue: omnibus-gitlab#1767 (closed)
• MR: omnibus-gitlab!1158 (merged)

I have confirmed that the ssh port can be set to a custom port with the following docker compose file, even in the current version.

services:
  gitlab:
    image: 'gitlab/gitlab-ee:16.11.2-ee.0'
    container_name: gitlab
    restart: always
    hostname: '<hostname>'
    environment:
      GITLAB_OMNIBUS_CONFIG: |
        external_url 'https://<hostname>'
        gitlab_rails['gitlab_shell_ssh_port'] = 2222
    ports:
      - '80:80'
      - '443:443'
      - '2222:22'
    volumes:
      - '/srv/gitlab/config:/etc/gitlab'
      - '/srv/gitlab/logs:/var/log/gitlab'
      - '/srv/gitlab/data:/var/opt/gitlab'
    shm_size: '256m'

Edit: I would add some evidences that the above docker compose file works.

• Confirmed that the docker is listening the port 2222 in the host

[ec2-user@ip-172-31-8-14 ~]$ sudo netstat -apn | grep 2222
tcp        0      0 0.0.0.0:2222            0.0.0.0:*               LISTEN      9031/docker-proxy   
tcp6       0      0 :::2222                 :::*                    LISTEN      9037/docker-proxy   
[ec2-user@ip-172-31-8-14 ~]$ docker ps | grep gitlab-ee
828e04d9cd51   gitlab/gitlab-ee:16.11.2-ee.0   "/assets/wrapper"        About an hour ago   Up About an hour (healthy)   0.0.0.0:80->80/tcp, :::80->80/tcp, 0.0.0.0:443->443/tcp, :::443->443/tcp, 0.0.0.0:2222->22/tcp, :::2222->22/tcp   gitlab

• Confirmed that the ssh is listening the port 22 in the container even gitlab_rails['gitlab_shell_ssh_port'] = 2222 is set.

[ec2-user@ip-172-31-8-14 ~]$ docker exec -ti gitlab lsof -i -n
COMMAND PID USER   FD   TYPE DEVICE SIZE/OFF NODE NAME
sshd     34 root    3u  IPv4  42850      0t0  TCP *:22 (LISTEN)
sshd     34 root    4u  IPv6  42851      0t0  TCP *:22 (LISTEN)
nginx   614 root    9u  IPv4  45568      0t0  TCP *:80 (LISTEN)
nginx   614 root   10u  IPv4  45569      0t0  TCP *:443 (LISTEN)
nginx   614 root   11u  IPv4  45570      0t0  TCP *:5050 (LISTEN)
nginx   614 root   12u  IPv4  45571      0t0  TCP *:8060 (LISTEN)

• Confirmed that the user can do git clone via SSH that is using port 2222

kkamiya@KosukenoMacBook-Pro:~/repo$ git clone ssh://git@docker.kkamiya-sandbox.com:2222/test/test2.git
Cloning into 'test2'...
remote: Enumerating objects: 3, done.
remote: Counting objects: 100% (3/3), done.
remote: Compressing objects: 100% (2/2), done.
remote: Total 3 (delta 0), reused 0 (delta 0), pack-reused 0
Receiving objects: 100% (3/3), done.

Related issues

omnibus-gitlab#1767 (closed)

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