Building and Deploying Docker Containers Using GitLab CI Pipelines

As part of migrating this blog to Docker containers to move to a different VPS provider (here, here and here), I found myself repeating a number of steps manually, which always a good indication that there's an opportunity to automate some or all of those steps.

Each time I made a change in the configuration or changed the content to be deployed, I found myself rebuilding the Docker image and either running locally, pushing to my test server, and eventually pushing to my prod VPS and running there.

I'm using a locally running GitLab for my version control, so to use its build pipeline features was a natural next step. I talked about setting up a GitLab runner previously here - this is what performs the work for your pipeline.

You configure your pipeline with a .gitlab-ci.yml file in the root of your repo. I defined 2 stages, build and deploy:

stages:
 - build
 - deploy

For my build stage, I have a single task which is to build my images using my docker-compose.yml:

build:
 stage: build
 script:
 - docker-compose build
 tags:
 - docker-test

For my deploy steps, I defined one for deploying to my test server, and one for deploying to my production VPS. This is the deploy to my locally running Docker server. It changes DOCKER_HOST to point to my test server, and then uses the docker-compose.yml again to bring down the running containers, and bring up the new containers with the updated images:

deploy-containers:
 stage: deploy
 script:
 - export DOCKER_HOST=tcp://192.x.x.x:2375
 - docker-compose down
 - docker-compose up -d
 tags:
 - docker-test

And one for my deploy to production. Note that this step is defined with 'when: manual' which tells GitLab the task is only run manually (when you click on the '>' run icon):

prod-deploy-containers:
 stage: deploy
 script:
 - pwd && ls -l
 - ./docker-compose-vps-down.sh
 - ./docker-compose-vps-up.sh
 when: manual
 tags:
 - docker-prod

Here's what the complete pipeline looks like in GitLab:

With this in place, now any changes committed to the repo result in a new image created and pushed to my test server automatically, and when I've completed testing the changes I can optionally deploy the changes to my prod VPS hosted server.