Gitlab Runner with Docker and shell error — Permission denied - docker

Question

Installed a brand new Gitlab CE 13.9.1 on a Ubuntu Server 20.04.2.0.
This is the pipeline
image: node:latest
before_script:
- apt-get update -qq
stages:
- install
install:
stage: install
script:
- npm install --verbose
To run it I configure my Gitlab Runner using the same procedure as in my previous Gitlab CE 12:
I pull last Gitlab runner image:
docker pull gitlab/gitlab-runner:latest
First try:
Start GitLab Runner container mounting on local volume
docker run -d \
--name gitlab-runner \
--restart always \
-v /srv/gitlab-runner/config:/etc/gitlab-runner \
-v /var/run/docker.sock:/var/run/docker.sock \
gitlab/gitlab-runner:latest
And register runner
docker run --rm -t -i \
-v /srv/gitlab-runner/config:/etc/gitlab-runner gitlab/gitlab-runner register
When registering runner, for executor I pick shell
Finally, when I push to Gitlab, on the pipeline, I see this error:
$ apt-get update -qq
E: List directory /var/lib/apt/lists/partial is missing. - Acquire (13: Permission denied)
ERROR: Job failed: exit status 1
Second try:
Start GitLab Runner container mounting on Docker volume
Create volume
docker volume create gitlab-runner-config
Start GitLab Runner container
docker run -d \
--name gitlab-runner \
--restart always \
-v gitlab-runner-config:/etc/gitlab-runner \
-v /var/run/docker.sock:/var/run/docker.sock \
gitlab/gitlab-runner:latest
Register runner (picking shell again as executor)
docker run \
--rm -t -i \
-v gitlab-runner-config:/etc/gitlab-runner gitlab/gitlab-runner register
Same results.
$ apt-get update -qq
E: List directory /var/lib/apt/lists/partial is missing. - Acquire (13: Permission denied)
ERROR: Job failed: exit status 1
Third try:
Granting permissions to gitlab-runner
I ended up reading In gitlab CI the gitlab runner choose wrong executor and https://docs.gitlab.com/runner/executors/shell.html#running-as-unprivileged-user, which states these solutions:
move to docker
grant user gitlab-runner the permissions he needs to run specified commands. gitlab-runner may run apt-get without sudo, also he will need perms for npm install and npm run.
grant sudo nopasswd to user gitlab-runner. Add gitlab-runner ALL=(ALL) NOPASSWD: ALL (or similar) to /etc/sudoers on the machine gitlab-runner is installed and change the lines apt-get update to sudo apt-get update, which will execute them as privileged user (root).
I need to use shell
I already did that with sudo usermod -aG docker gitlab-runner
Tried as well with sudo nano /etc/sudoers, adding gitlab-runner ALL=(ALL) NOPASSWD: ALL, and using sudo apt-get update -qq in the pipeline, which results in bash: line 106: sudo: command not found
I'm pretty lost here now. Any idea will be welcome.

Answer 1

IMHO, using shell executor on a Docker runner with already mounted Docker socket on it is not a good idea. You'd better use docker executor, which will take care of everything and probably is how it's supposed to be run.
Edit
Alternatively, you can use a customized Docker image to allow using the shell executor with root permissions. First, you'll need to create a Dockerfile:
FROM gitlab/gitlab-runner:latest
# Change user to root
USER root
Then, you'll have to build the image (here, I tagged it as custom-gitlab-runner):
$ docker build -t custom-gitlab-runner .
Finally, you'll need to use this image:
docker run -d \
--name gitlab-runner \
--restart always \
-v /srv/gitlab-runner/config:/etc/gitlab-runner \
-v /var/run/docker.sock:/var/run/docker.sock \
custom-gitlab-runner:latest

Answer 2

I had a similar issue trying to use locally installed gitlab-runner on ubuntu with a shell executor (I had other issues using docker executor not being able to communicate between stages)
$ docker build -t myapp .
Got permission denied while trying to connect to the Docker daemon socket at unix:///var/run/docker.sock: Post "http://%2Fvar%2Frun%2Fdocker.sock/v1.24/build?buildargs=%7B%7D&cachefrom=%5B%5D&cgroupparent=&cpuperiod=0&cpuquota=0&cpusetcpus=&cpusetmems=&cpushares=0&dockerfile=Dockerfile&labels=%7B%7D&memory=0&memswap=0&networkmode=default&rm=1&shmsize=0&t=myapp&target=&ulimits=null&version=1": dial unix /var/run/docker.sock: connect: permission denied
ERROR: Job failed: exit status 1
I then printed what user was running the docker command within the gitlab-ci.yml file, which was gitlab-runner
...
build:
script:
- echo $USER
- docker build -t myapp .
...
I then added gitlab-runner to the docker group using
sudo usermod -aG docker gitlab-runner
which fixed my issue. No more docker permission errors.