How do I enable cloning over SSH for a Gitlab runner?

Question

I am having some trouble cloning large repositories over HTTP on my Windows Gitlab runner. I\'ve tried several methods to do shallow clones or disable clone compression. Sti

Answer 1

I had a similar problem that necessitated the use of cloning via ssh: using the virtualbox executor with very old guest linux OSes. I was able to get around it by doing a few small configuration changes:

1. Create a deploy key for access to the project.

2. Force the user account that will perform the clone to use the deploy key. In my virtualbox case, I modified the ssh configuration for the user that's configured for virtualbox in /etc/gitlab-runnner/config.toml.

~/.ssh/config

Host gitlab.example.com
  Preferredauthentications publickey
  IdentityFile ~/.ssh/deploy-key

3. Configure the runner to perform the clone via ssh in /etc/config.toml.

/etc/config.toml

[[runners]]

  # [...]

  environment = ["GIT_STRATEGY=none"]
  pre_build_script = '''
    # Fetching using ssh (via pre_build_script in config.toml)
    if [ -d "${CI_PROJECT_DIR}" ]; then rm -rf "${CI_PROJECT_DIR}"; fi
    mkdir -p "${CI_PROJECT_DIR}"
    cd "${CI_PROJECT_DIR}"
    git init
    git remote add origin "ssh://git@${CI_SERVER_HOST}/${CI_PROJECT_PATH}.git"
    git fetch origin "${CI_COMMIT_SHA}"
    git reset --hard FETCH_HEAD
  '''

  # [...]

Here's a breakdown of the additions to config.toml:

• The GIT_STRATEGY=none environment variable disables the runner's internal git cloning mechanism. (See the Git Strategy section of the CI/CD reference)
• The pre_build_script performs the actual clone using predefined CI/CD environment variables. In my case, this is a bash script to perform something similar to what a GIT_STRATEGY=fetch might do.
• If pre_build_script is multi-line, the output of the runner will only show the first line. Having a comment as the first line helps add clarity to the runner output.
• pre_clone_script is not used here. It's disabled since the environment has GIT_STRATEGY=none set.