gitlab-runner Could not resolve host: gitlab.com

Question

I have a raspberry pi with gitlab-runner installed (linux version) and a git repository on gitlab.com (not self hosted).

At the beginning of pipeline, gitlab-runner on raspberry try to fetch the .git repo but I get :

Could not resolve host: gitlab.com

I tried :

• ping gitlab.com is ok on the raspberry
• Add extra_host = ['localhost:my.ip.ad.ress] --> No changes
• Add netword_mode = "gitlab_default" like this, And get :

This error :

Error response from daemon: network gitlab_default not found (exec.go:57:1s)

I am in the simplest configuration with repo on gitlab.com and a gitlab-runner on raspberry. How can I deal with it ?

Here is the config.toml :

concurrent = 1
check_interval = 0

[session_server]
  session_timeout = 1800

[[runners]]
  name = "gitlab runner on raspberryPi"
  url = "https://gitlab.com/"
  token = "XXXX"
  executor = "docker"
  [runners.custom_build_dir]
  [runners.cache]
    [runners.cache.s3]
    [runners.cache.gcs]
    [runners.cache.azure]
  [runners.docker]
    tls_verify = false
    image = "node:latest"
    privileged = false
    disable_entrypoint_overwrite = false
    oom_kill_disable = false
    disable_cache = false
    volumes = ["/cache"]
    shm_size = 0

Answer 1

I had same issue , my gitlab-runner was running on my local. I restarted my docker

systemctl restart docker

and error went away.

Answer 2

Not being able to resolve the host name can have multiple root-causes:

IP forwarding disabled?

Routing might be disabled on your system. Check if IP forwarding is enabled (== 1).

cat /proc/sys/net/ipv4/ip_forward
1

If it's disabled, it will return 0, please enable it by editing a sysctl file. For example edit and add: /etc/sysctl.d/99-sysctl.conf:

net.ipv4.conf.all.forwarding = 1
net.ipv4.ip_forward = 1

Apply the setting without rebooting: sudo sysctl --system

Important Note: Even if the system is reporting that IP forwarding is currently enabled, you might want to set to explicitly and correctly in your sysctl configs. Since Docker will run sysctl -w net.ipv4.ip_forward=1 when the Daemon starts-up. But that is not a persistent setting, and might cause very random issues!! Like you have.

DNS missing / invalid?

You can try if setting a DNS server to 8.8.8.8 might fix the problem:

 [runners.docker]
    dns = ["8.8.8.8"]

Add extra_host?

You can also try to add an extra host, which might be mainly relevant within a local network (so not with gitlab.com domain).

 [runners.docker]
    extra_hosts = ["gitlab.yourdomain.com:192.168.xxx.xxx"]

Using host network

I really do not advise this, but you could configure the Docker container to run with network_mode as "host". Again, only do this for debugging reasons:

 [runners.docker]
   network_mode = "host"