install-ssh-agent

.deploy_job: &deploy_job
  before_script:
    # Install ssh-agent if not already installed, it is required by Docker.
    # (change apt-get to yum if you use a CentOS-based image)
    - 'which ssh-agent || ( apt-get update -y && apt-get install openssh-client -y ) || (apk update && apk add openssh-client)'

    # Run ssh-agent (inside the build environment)
    - eval $(ssh-agent -s)

    # Add the SSH key stored in SSH_PRIVATE_KEY variable to the agent store
    - mkdir -m 700 -p ~/.ssh
    - echo "$SSH_PRIVATE_KEY" > ~/.ssh/id_rsa
    - chmod 600 ~/.ssh/id_rsa
    - apt-get install -y sshpass || apk add --update sshpass
    - sshpass -p "" ssh-add ~/.ssh/id_rsa

    # For Docker builds disable host key checking. Be aware that by adding that
    # you are suspectible to man-in-the-middle attacks.
    # WARNING: Use this only with the Docker executor, if you use it with shell
    # you will overwrite your user's SSH config.
    - mkdir -p ~/.ssh
    - '[[ -f /.dockerenv ]] && echo -e "Host *\n\tStrictHostKeyChecking no\n\n" > ~/.ssh/config'
    # In order to properly check the server's host key, assuming you created the
    # SSH_SERVER_HOSTKEYS variable previously, uncomment the following two lines
    # instead.
    - mkdir -p ~/.ssh
    - '[[ -f /.dockerenv ]] && echo "$SSH_SERVER_HOSTKEYS" > ~/.ssh/known_hosts'