Master GitLab CI: From Code to Docker Deployment in Minutes

1. Preparation

Set up a GitLab instance (using the hosted service for convenience) and a target server that has Docker and GitLab Runner installed (e.g., a CentOS 7 64‑bit machine). Use a sample Go project ( testgolang) from the official GitLab repository as the source code.

Create a Dockerfile to build the Go binary and package it into an image, and a .gitlab-ci.yml file that defines the CI/CD pipeline.

# Dockerfile example
FROM golang:latest
MAINTAINER William "[email protected]"
WORKDIR $GOPATH/src/chinaase.com/testgolang
COPY . $GOPATH/src/chinaase.com/testgolang
RUN go build .
EXPOSE 8001
ENTRYPOINT ["./testgolang"]

# .gitlab-ci.yml example
stages:
  - deploy

docker-deploy:
  stage: deploy
  script:
    - docker build -t testgolang .
    - if [ $(docker ps -aq --filter name=testgolang) ]; then docker rm -f testgolang; fi
    - docker run -d -p 8001:8001 --name testgolang testgolang
  tags:
    - mbp13
  only:
    - golang

2. Environment Configuration

Register a runner on the target server and link it to the GitLab project. The runner is identified by the tag mbp13, which is used in the pipeline definition to select the execution node.

Typical registration steps involve obtaining the registration token from GitLab and executing:

sudo gitlab-runner register
# Follow prompts to provide URL, token, description, tags (e.g., mbp13), and executor (docker)

Additional commands to ensure the runner can use Docker:

sudo groupadd docker
sudo gpasswd -a gitlab-runner docker
newgrp docker
sudo docker ps   # verify Docker works without sudo

3. Commit Updates and Automatic Deployment

Push changes to the golang branch. GitLab CI automatically detects the push, reads .gitlab-ci.yml, and starts the defined job.

The pipeline builds the Docker image, removes any existing container with the same name, and runs a new container exposing port 8001.

Job results are visible under the CI/CD → Jobs section in GitLab.

4. Access the Deployed Service

After the pipeline finishes, the Go application is reachable at http://127.0.0.1:8001/hello.

5. Supplement: Deploying GitLab Itself with Docker

For a self‑hosted GitLab instance, run the following commands:

docker pull beginor/gitlab-ce:11.3.0-ce.0

docker run --detach \
  --publish 8443:443 \
  --publish 8880:80 \
  --publish 8822:22 \
  --name my-gitlab \
  --restart unless-stopped \
  --volume /Users/ys/05Docker_workspace/gitlab/etc:/etc/gitlab \
  --volume /Users/ys/05Docker_workspace/gitlab/log:/var/log/gitlab \
  --volume /Users/ys/05Docker_workspace/gitlab/data:/var/opt/gitlab \
  --privileged=true \
  beginor/gitlab-ce:11.3.0-ce.0

6. Prerequisite Knowledge

Basic Docker commands

Git command usage

GitLab operation basics

Writing a .gitlab-ci.yml file

Programming language fundamentals (Go used in examples)