GitLab and Docker registry on seperate servers

Question

I'm a little bit desperate and starting to going mad. I tried to configure my gitlab instance (omnibus) to work with external private docker image registry. Initialy I thought is should be relatively easy task. But now I totaly confused.

My initial installation looked like this:

• generate selfsigned cert
• clear instance of docker registry on Ubuntu 18.04 with docker-compose and nginx. Secured with letsEncrypt on registry.domain.com I use following script:

version: '3'

        services:
          registry:
            restart: always
            image: registry:2
            ports:
            - "5000:5000"
            environment:
              REGISTRY_AUTH: token
              REGISTRY_AUTH_TOKEN_REALM: https://registry.domain.com:5000/auth
              REGISTRY_AUTH_TOKEN_SERVICE: "Docker registry"
              REGISTRY_AUTH_TOKEN_ISSUER: "gitlab-issuer"
              REGISTRY_AUTH_TOKEN_ROOTCERTBUNDLE: /etc/gitlab/registry-certs/registry-auth.crt
              REGISTRY_STORAGE_FILESYSTEM_ROOTDIRECTORY: /data
            volumes:
              - ./auth:/auth
              - ./data:/data

• clear instance of gitlab on Ubuntu 18.04. Secured with letsEncrypt on gitlab.domain.com

• some changes in gitlab.rb like:

    registry_external_url ‘https://registry.domain.com/’
    gitlab_rails[‘registry_enabled’] = true
    gitlab_rails[‘registry_host’] = “registry.domain.com”
    gitlab_rails[‘registry_port’] = “5000”

    gitlab_rails[‘registry_api_url’] = “htps://registry.prismstudio.space:5000”
    gitlab_rails[‘registry_key_path’] = “/etc/gitlab/registry-certs/registry-auth.key”
    gitlab_rails[‘registry_issuer’] = “gitlab-issuer”

After gitlab-ctl reconfigure i receive letsEncrypt error:

letsencrypt_certificate[gitlab.domain.net] (letsencrypt::http_authorization line 5) had an error: RuntimeError: acme_certificate[staging] (/opt/gitlab/embedded/cookbooks/cache/cookbooks/letsencrypt/resources/certificate.rb line 25) had an error: RuntimeError: ruby_block[create certificate for gitlab.domain.net] (/opt/gitlab/embedded/cookbooks/cache/cookbooks/acme/resources/certificate.rb line 108) had an error: RuntimeError: [gitlab.domain.com] Validation failed, unable to request certificate

I literary try everything but nothing helps me.

Is there any straightforward way to se tup GitLab server with external Docker registry? How to configure it properly? I'm open to burn everything to the ground and make it once again with working configuration.