.gitlab.ci.yml for SSH with private key.

.gitlab.ci.yml

# Image neeeds to have ssh-client
image: docker:git

services:
  - docker:dind

stages:
  - staging
before_script:
  - docker login -u gitlab-ci-token -p $CI_BUILD_TOKEN $CI_REGISTRY
  - mkdir -p ~/.ssh
  # Paste the PRIVATE key into a gitlab variable. Pay attention to the linebreak at the end when pasting
  - echo "$DEPLOY_SERVER_PRIVATE_KEY" | tr -d '\r' > ~/.ssh/id_rsa
  - chmod 600 ~/.ssh/id_rsa
  - eval "$(ssh-agent -s)"
  - ssh-add ~/.ssh/id_rsa
  - ssh-keyscan -H 'your.server.hostname' >> ~/.ssh/known_hosts

staging:
  stage: staging
  tags:
    - docker
  only:
    - staging
  script:
    - docker build --pull -t $CI_REGISTRY_IMAGE:staging .
    - docker push $CI_REGISTRY_IMAGE:staging
    # your own server details here
    - ssh $SERVER_USER@$SERVER_HOSTNAME < deploy.sh

Thanks @amatiash !

How to add multiple Private keys to known_host??

Hey all, just tackled this today. FYI, this is how you can do git operations (i.e. tagging) from within CI as of today (variable of type 'File'):

tagging_job:
  stage: release
  image: ubuntu
  before_script:
    - mkdir -p ~/.ssh
    # Settings > Repository > Deploy Keys > "DEPLOY_KEY_PUBLIC" is the public key of the utitlized SSH pair (choose `Write access allowed` on creation)
    # Settings > CI/CD > Variables > "DEPLOY_KEY_PRIVATE" is the private key of the utitlized SSH pair, type is 'File' and ends with empty line
    - mv "$DEPLOY_KEY_PRIVATE" ~/.ssh/id_rsa
    - chmod 600 ~/.ssh/id_rsa
    - 'which ssh-agent || ( apt-get update -y && apt-get install openssh-client git -y )'
    - eval "$(ssh-agent -s)"
    - ssh-add ~/.ssh/id_rsa
    - ssh-keyscan -H 'gitlab.com' >> ~/.ssh/known_hosts
  script:
    # try to connect to GitLab.com
    - ssh git@gitlab.com
    # fresh clone
    - mkdir ~/source && cd $_
    - git clone git@gitlab.com:$CI_PROJECT_PATH.git
    - cd $CI_PROJECT_NAME
    # Version tag
    - git tag my-tag
    - git push --tags -o ci.skip

The -o ci.skip part causes the generated pipeline to be skipped (not auto-ran). If you want to not generate a pipeline at all for your tag push, add this to the top of the .gitlab-ci.yml:

workflow:
  rules:
    - if: $CI_COMMIT_TAG
      when: never
    - when: always

Peace

Thx, you made my day !