(SOLVED) Gitlab CI – docker: command not found

If you get this error in the job of GitLab CI

docker: command not found
ERROR: Job failed: exit code 1

The solution is :

To run Docker commands in your CI/CD jobs, you must configure GitLab Runner to enable docker support.

To enable it, there are three ways to enable the use of docker build and docker run during jobs :

• The shell executor
• The Docker executor with the Docker image (Docker-in-Docker)
• Docker socket binding

References :

https://docs.gitlab.com/ee/ci/docker/using_docker_build.html