Фатальный: не удалось установить Gitlab-Runner: Service Gitlab-Runner уже существует

Rename the init file with

sudo mv /etc/systemd/system/gitlab-runner.service  /etc/systemd/system/gitlab-runner.service.bak
and execute again

sudo gitlab-runner install --user=my-user --working-directory=/home/my-user
cleanup the backup file

sudo rm /etc/systemd/system/gitlab-runner.service.bak
BoomSlang Frikkie