A simple example for a docker deployment with Gitlab CE and the built-in docker registry. Just a starting point for dev-deployments with Gitlab tools. No need for extra CI Tools.

We will use:

• Gitlab as VCS
• Gitlab as Docker registry
• Gitlab as CI / CD deployment tool

We will run all of the dependencies in docker containers:

• Gitlab
• Gitlab runner
• Docker dind

We will use https://gitlab/ as host so make sure you have added it in your /etc/hosts file.

For the example docker configuration check the docker-compose.yml provided by this project.
Now let's bring up the containers we need with:

docker-compose up

After a short startup (and initialisation of each container) the project should be running.
(For the first start it will take some minutes. We are done when you reach https://gitlab/ via your browser)

You can verify that all containers where bring up correctly by

$ docker ps
CONTAINER ID  IMAGE                        COMMAND                 CREATED            STATUS         NAMES
c05e61d16a34  gitlab/gitlab-ce:latest      "/assets/wrapper"       12 seconds ago     Up 11 seconds  gitlab
dde31f19a26c  gitlab/gitlab-runner:latest  "/usr/bin/dumb-init …"  12 seconds ago     Up 11 seconds  runner
23eed28af396  docker:18.05.0-ce-dind       "dockerd-entrypoint.…"  About an hour ago  Up 11 seconds  registry

Fine, everything is running!

Do not forget to add your SSH key in Gitlab backend for communicate via SSH with Gitlab.

We need the IP of the host (wich is running the compose file). In my case its my local maschine, so to grab your ip you could use something like:

ip route get 1 | awk '{print $NF;exit}'
# or
ip route get 8.8.8.8 | awk '{print $NF; exit}'
# or
hostname -I | cut -d' ' -f1
...

and copy the IP for the next step:

Now it's time to setup and register our runner for Gitlab. We need a registration token from Gitlab to register our runner.

Go to https://gitlab/admin/runners and copy your token under the "Setup a shared Runner manually" section.

Now we will login to the runner container

docker exec -it runner bash

and execute the register runner script (change the token and IP you copied before):

gitlab-runner register -n \
  --url https://gitlab/ \
  --registration-token TOKEN_FROM_GITLAB \
  --executor docker \
  --description "Docker Runner" \
  --docker-image "docker:stable" \
  --docker-privileged \
  --docker-extra-hosts "gitlab:IP_FROM_SERVER_WHERE_COMPOSE_IS_RUNNING" \
  --docker-volumes "/var/run/docker.sock:/var/run/docker.sock"

If everything went fine you should see a console output like this:

Runner registered successfully. Feel free to start it, but if it's running already the config should be automatically reloaded! 

and see the runner in Gitlabs backend when you refresh https://gitlab/admin/runners.

Great, you registered your runner

Now we will make a fresh project repository. Let's call it application in our new Gitlab.
For this example we will use a basic NGINX webserver. So create a new file called Dockerfile in your new repository with this content:

FROM nginx:latest
RUN echo "<h1>Deployment</h1>" > /usr/share/nginx/html/index.html

That's all for our basic application, cos we want to test the deployment and dont want to make a big application.

Again got to https://gitlab/admin/runners and "edit" the runner for taking effect on our new project (enable it).

Our runner need to know what to exactly to do for our project. That we will define in a file called .gitlab-ci.yml. Create this file in our application repository and after finish push the new changes to the repo.

image: docker:stable

variables:
  DOCKER_DRIVER: overlay2

build:
  stage: build
  script:
    - docker login -u gitlab-ci-token -p $CI_JOB_TOKEN $CI_REGISTRY
    - docker build -t gitlab:4567/root/application:dev .
    - docker push gitlab:4567/root/application:dev

you can find the instructions to pull/push to the gitlab docker registry in the registry tab of the repo navigation.

And if you now push the changes to Gitlab, the pipeline will start as soon as Gitlab receive your push. Go to CI / CD --> pipelines in Gitlab menu of your repo and check your build state.

GREAT
You just run your first docker deployment

No its time test the image locally. First we will login to our gitlab registry:

docker login gitlab:4567

after that we will pull the image:

docker pull gitlab:4567/root/application:dev

and now run it:

docker run -p "8080:80" gitlab:4567/root/application:dev

Now you should see a output on http://localhost:8080/ like this:

Deployment

I have added some dummy SSL certificates and a root CA certificate to let the systems trust the certificates.
You should generate and use your own certificates! (see docker-compose.yml volumes)
See my Local SSL repository for generating your own certs.