Cannot connect to the Docker daemon - Gitlab runner on Kubernetes

My issue is similar to gitlab-org/gitlab-foss#34419 (closed) but I'm creating a new one because

  1. The original issue is closed.
  2. None of the suggested answers is working for me.
  3. Issue template in gitlab-foss is pointing to this repository.

I'm running a Gitlab server v12.5.3-ee on a Kubernetes cluster v1.15.6. The Gitlab server (and runner) has been built using the official Gitlab Helm chart with the following values:

certmanager:
  install: false
certmanager-issuer:
  email: ####
gitlab-runner:
  runners:
    privileged: true
global:
  email:
    display_name: ####
    from: ####
    reply_to: ####
  hosts:
    domain: ####
    https: false
  ingress:
    annotations:
      kubernetes:
        io/tls-acme: true
    tls:
      enabled: false
  smtp:
    address: smtp.gmail.com
    authentication: login
    enabled: true
    openssl_verify_mode: peer
    password:
      secret: smtp-gmail
    port: 587
    starttls_auto: true
    user_name: ####

AutoDevOps pipelines are working but I'm not able to have custom ci/cd working with .gitlab-ci.yml file. this is my .gitlab-ci.yml:

image: docker:git
services:
  - docker:18.09.7-dind
variables:
  DOCKER_DRIVER: overlay

before_script:
  - docker info

build:
  script: 
    - echo 'this is the script'
    - docker build -t frontend .
    - docker run -v ${PWD}:/app -v /app/node_modules -p 4200:4200 --rm frontend
    - docker tag frontend registry.gitlab.com:5000/frontend
    - docker push registry.gitlab.com:5000/frontend

What I already tried:

  • Replace docker:git image by docker:latest
  • Using 19.03.0-dind image
  • Adding DOCKER_HOST: tcp://localhost:2375 variable

When installing Gitlab with Helm chart I've been passing the gitlab-runner.runners.privileged=true as we can see in my Helm chart values. I assume my runner is in privileged mode because at first it wasn't and AutoDevOps was facing the same error but after enabling it via Helm chart the AutoDevOps started to work.

However what seems a bit strange is that if I run kubectl describe configmap gitlab-gitlab-runner -n gitlab on my cluster, the config.toml is not showing the privileged attribute:

config.toml:
----
concurrent = 10
check_interval = 30
log_level = "info"
listen_address = '[::]:9252'

However I'm not sure how Helm chart assign the privileged attribute. I'm also not able to access the config.toml file inside the container by doing an exec as the owner of the file is "root".

Am I missing something on how to use custom CI/CD on a Kubernetes runner ?

Thanks.