Error 502 after Pages Deploy

GitLab CI/CD
1

I have recently deployed GitLab with GitLab Pages on our local environment. Its a linux hosted instance of GitLab 17.3.1 and is deployed behind a Traefik reverse proxy. I also deployed a runner on a separate container to build the Docker files.

I am trying to deploy the HTML Pages template, but I cannot seem to get it working. The build and deploy process is successful according to the job report, however, I cannot access the deployed page or even the artifact. Both give an error 502. I have tried every setting I could find, even just the plain wildercard domain directly to GitLab (without going through Traefik) and I always get the same error 502.

I need help please.

a.b.c.d = replace the IP address
x.y.z = replaced our domain

Below is an extract of the gitlab.rb file:

nginx['listen_https'] = false
nginx['proxy_set_headers'] = {"X-Forwarded-Proto" => "https","X-Forwarded-Ssl" => "on"}
nginx['listen_addresses'] = ['a.b.c.d']
nginx['listen_port'] = 80
letsencrypt['enable'] = false
external_url 'https://gitlab.x.y.z'

pages_external_url 'https://docs.x.y.z'
gitlab_pages['enable'] = true
pages_nginx['listen_https'] = false
pages_nginx['listen_port'] = 15002
pages_nginx['proxy_set_headers'] = {"X-Forwarded-Proto" => "https","X-Forwarded-Ssl" => "on"}

Here is the .gitlab-ci.yml file:

# This file is a template, and might need editing before it works on your project. 
# Full project: https://gitlab.com/pages/plain-html

image: busybox

pages:
  stage: deploy
  script:
    - echo "The site will be deployed to $CI_PAGES_URL"
  artifacts:
    paths:
      - public
  rules:
    - if: $CI_COMMIT_BRANCH == $CI_DEFAULT_BRANCH

Running with gitlab-runner 17.3.1 (66269445)
[2] on Gitlab-runner1 qsyc9Vnh9, system ID: s_9b6fc9f7e1e2
[3]Preparing the "docker" executor00:02
[4]Using Docker executor with image busybox ...
[5]Pulling docker image busybox ...
[6]Using docker image sha256:87ff76f62d367950186bde563642e39208c0e2b4afc833b4b3b01b8fef60ae9e for busybox with digest busybox@sha256:34b191d63fbc93e25e275bfccf1b5365664e5ac28f06d974e8d50090fbb49f41 ...
[7]Preparing environment00:00
[8]Running on runner-qsyc9vnh9-project-13-concurrent-0 via Gitlab-runner...
[9]Getting source from Git repository00:02
[10]Fetching changes with git depth set to 20...
[11]Reinitialized existing Git repository in /builds/cyberrange/doctest/.git/
[12]Checking out 183e947b as detached HEAD (ref is master)...
[13]Skipping Git submodules setup
[14]Executing "step_script" stage of the job script00:00
[15]Using docker image sha256:87ff76f62d367950186bde563642e39208c0e2b4afc833b4b3b01b8fef60ae9e for busybox with digest busybox@sha256:34b191d63fbc93e25e275bfccf1b5365664e5ac28f06d974e8d50090fbb49f41 ...
[16]$ echo "The site will be deployed to $CI_PAGES_URL"
[17]The site will be deployed to https://cyberrange.docs.x.y.z/doctest
[18]Uploading artifacts for successful job00:01
[19]Uploading artifacts...
[20]public: found 3 matching artifact files and directories
[21]Uploading artifacts as "archive" to coordinator... 201 Created id=79 responseStatus=201 Created token=glcbt-64
[22]Job succeeded

GitLab Pages Error log:

{"correlation_id":"01J710DHMD461Y5FWBWA06SH4Q","error":"invalid character '\u003c' looking for beginning of value","host":"cyberrange.docs.x.y.z","level":"error","msg":"could not fetch domain information from a source","path":"/doctest","time":"2024-09-05T13:51:49+02:00"}
{"content_type":"text/html; charset=utf-8","correlation_id":"01J710DHMD461Y5FWBWA06SH4Q","duration_ms":0,"host":"cyberrange.docs.x.y.z","level":"info","method":"GET","msg":"access","pages_https":true,"proto":"HTTP/1.1","referrer":"","remote_addr":"10.1.1.15","remote_ip":"10.1.1.15","status":502,"system":"http","time":"2024-09-05T13:51:49+02:00","ttfb_ms":0,"uri":"/doctest","user_agent":"Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/128.0.0.0 Safari/537.36","written_bytes":2905}
{"correlation_id":"01J710DHMV4Y4VE71NSBN5KXCB","error":"invalid character '\u003c' looking for beginning of value","host":"cyberrange.docs.x.y.z","level":"error","msg":"could not fetch domain information from a source","path":"/favicon.ico","time":"2024-09-05T13:51:49+02:00"}
{"content_type":"text/html; charset=utf-8","correlation_id":"01J710DHMV4Y4VE71NSBN5KXCB","duration_ms":0,"host":"cyberrange.docs.x.y.z","level":"info","method":"GET","msg":"access","pages_https":true,"proto":"HTTP/1.1","referrer":"https://cyberrange.docs.x.y.z/doctest","remote_addr":"10.1.1.15","remote_ip":"10.1.1.15","status":502,"system":"http","time":"2024-09-05T13:51:49+02:00","ttfb_ms":0,"uri":"/favicon.ico","user_agent":"Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/128.0.0.0 Safari/537.36","written_bytes":2905}
2

I finally managed to get it working. The problem was that the Pages instance was trying to connect to the GitLab instance API, but was redirected to Traefik (and Authentik) which was obviously causing issues. I had to specify the docs and gitlab IPs in the hosts file (pointing to 127.0.0.1) as well as made some changes to the gitlab.rb file and traefik rules.

My final working gitlab.rb file for those that need help is:

nginx['listen_https'] = false
nginx['redirect_http_to_https'] = false
nginx['listen_addresses'] = ['10.1.2.12']
nginx['listen_port'] = 80
letsencrypt['enable'] = false
external_url 'https://gitlab.x.y.z'

pages_external_url 'https://docs.x.y.z'
gitlab_pages['enable'] = true
gitlab_pages['port'] = 8090
gitlab_pages['gitlab_server'] = 'http://gitlab.x.y.z'
gitlab_pages['log_verbose'] = true
pages_nginx['listen_https'] = false
gitlab_pages['external_http'] = ['10.1.2.13:80']
gitlab_pages['access_control'] = true
gitlab_pages['inplace_chroot'] = true