Gitlab CI cannot pull image from private docker registry - gitlab

Question

I'd like to create a Docker based Gitlab CI runner which pulls the docker images for the build from a private Docker Registry (v2). I cannot make the Gitlab Runner to pull the image from a local Registry, it tries to GET something from a /v1 API. I get the following error message:
ERROR: Build failed: Error while pulling image: Get http://registry:5000/v1/repositories/maven/images: dial tcp: lookup registry on 127.0.1.1:53: no such host
Here's a minimal example, using docker-compose and a web browser.
I have the following docker-compose.yml file:
version: "2"
services:
gitlab:
image: gitlab/gitlab-ce
ports:
- "22:22"
- "8080:80"
links:
- registry:registry
gitlab_runner:
image: gitlab/gitlab-runner
volumes:
- /var/run/docker.sock:/var/run/docker.sock
links:
- registry:registry
- gitlab:gitlab
registry:
image: registry:2
After the first Gitlab login, I register the runner into the Gitlab instance:
root#130d08732613:/# gitlab-runner register
Running in system-mode.
Please enter the gitlab-ci coordinator URL (e.g. https://gitlab.com/ci):
http://192.168.61.237:8080/ci
Please enter the gitlab-ci token for this runner:
tE_1RKnwkfj2HfHCcrZW
Please enter the gitlab-ci description for this runner:
[130d08732613]: docker
Please enter the gitlab-ci tags for this runner (comma separated):
Registering runner... succeeded runner=tE_1RKnw
Please enter the executor: docker-ssh+machine, docker, docker-ssh, parallels, shell, ssh, virtualbox, docker+machine:
docker
Please enter the default Docker image (eg. ruby:2.1):
maven:latest
Runner registered successfully. Feel free to start it, but if it's running already the config should be automatically reloaded!
After this, I see the Gitlab runner in my Gitlab instance:
After this I push a simple maven image to my newly created Docker repository:
vilmosnagy#vnagy-dell:~/$ docker tag maven:3-jdk-7 172.19.0.2:5000/maven:3-jdk7
vilmosnagy#vnagy-dell:~/$ docker push 172.19.0.2:5000/maven:3-jdk7
The push refers to a repository [172.19.0.2:5000/maven]
79ab7e0adb89: Pushed
f831784a6a81: Pushed
b5fc1e09eaa7: Pushed
446c0d4b63e5: Pushed
338cb8e0e9ed: Pushed
d1c800db26c7: Pushed
42755cf4ee95: Pushed
3-jdk7: digest: sha256:135e7324ccfc7a360c7641ae20719b068f257647231d037960ae5c4ead0c3771 size: 1794
(I got the 172.19.0.2 IP-address from a docker inspect command's output)
After this I create a test project in the Gitlab and add a simple .gitlab-ci.yml file:
image: registry:5000/maven:3-jdk-7
stages:
- build
- test
- analyze
maven_build:
stage: build
script:
- "mvn -version"
And after the build the Gitlab gives the error in seen in the beginning of the post.
If I enter into the running gitlab-runner container, I can access the registry under the given URL:
vilmosnagy#vnagy-dell:~/$ docker exec -it comptest_gitlab_runner_1 bash
root#c0c5cebcc06f:/# curl http://registry:5000/v2/maven/tags/list
{"name":"maven","tags":["3-jdk7"]}
root#c0c5cebcc06f:/# exit
exit
vilmosnagy#vnagy-dell:~/$
But the error still the same:
Do you have any idea how to force the gitlab-runner to use the v2 api of the private registry?

Answer 1

Current Gitlab and Gitlab Runners support this, see: https://docs.gitlab.com/runner/configuration/advanced-configuration.html#use-a-private-container-registry
On older Gitlab I've solved this with copying an auth key into ~/.docker/config.json
{
"auths": {
"my.docker.registry.url": {
"auth": "dmlsbW9zLm5hZ3k6VGZWNTM2WmhC"
}
}
}
I've logged into this container from my computer and copied this auth key into the Gitlab Runner's docker container.

Answer 2

What version of docker do you run on Gitlab ?
Also for a v2 registry, you have to explicitly allow insecure registry with a command line switch, or secure your registry using a certificate.
Otherwise Docker fallback to the v1 registry if it gets a security exception.