GitLab Runner supports multiple executors, but Shell and Docker are the most commonly used for C/C++ CI/CD pipelines on Linux.

• Both are easy to configure
• Selection depends on: System restrictions, Security policies and Resource availability

Executors Overview

Shell Executor

• Runs jobs directly on the host machine
• Requires manual installation of dependencies
• Faster execution (no container overhead)
• Limited isolation → potential dependency conflicts

Best for:

• Dedicated servers
• Controlled environments

Docker Executor

• Runs jobs inside containers
• No manual dependency setup required
• Provides isolated, reproducible builds
• Slight startup overhead

Best for:

• Team environments
• Scalable CI/CD pipelines
• Microservices architecture

C/C++ CI/CD with Shell Executor

Software Requirements

Install the following:

• Git : version control
• CMake : build automation
• GCC / G++ : C/C++ compilers
• grep : optional (for text processing in scripts)

Verify Installation

which git
gcc --version
g++ --version
cmake --version

GitLab Runner Setup (Linux)

1. Download Binary

sudo curl -L --output /usr/local/bin/gitlab-runner \
https://gitlab-runner-downloads.s3.amazonaws.com/latest/binaries/gitlab-runner-linux-amd64

2. Grant Execute Permission

sudo chmod +x /usr/local/bin/gitlab-runner

3. Create Runner User

sudo useradd --comment 'GitLab Runner' --create-home gitlab-runner --shell /bin/bash

4. Install as Service

sudo gitlab-runner install --user=gitlab-runner --working-directory=/home/gitlab-runner

5. Start Runner

sudo gitlab-runner start

Register Runner

sudo gitlab-runner register

Provide:

• GitLab instance URL (e.g., http://gitlab.example.com)
• Project registration token
  (GitLab → Project → Settings → CI/CD → Runners)
• Runner description (any name)
• Tags (optional but recommended)
• Executor: shell

Shell Executor: .gitlab-ci.yml

stages:

- build

- test

build_job:

stage: build

only:

- master

script:

- cd sourcecode

- chmod +x BuildPackage.sh

- ./BuildPackage.sh

artifacts:

expire_in: 7 days

paths:

- sourcecode/binaryfolder_name

test_job:

stage: test

only:

- master

script:

- cd testdir

- chmod +x tests.sh

- ./tests.sh

dependencies:

- build_job

Java CI/CD with Docker Executor

Key Advantages

• No manual installation required
• Clean, isolated environment
• Consistent builds across systems

Recommended Approach

• Use prebuilt images instead of installing packages every run
• Custom Docker images with required tools

Docker Executor: .gitlab-ci.yml

image: gcc:latest

stages:

- build

- test

before_script:

- apt-get update && apt-get install -y cmake

build_job:

stage: build

script:

- cd sourcecode

- chmod +x BuildPackage.sh

- ./BuildPackage.sh

artifacts:

expire_in: 7 days

paths:

- sourcecode/binaryfolder_name

test_job:

stage: test

script:

- cd testdir

- chmod +x tests.sh

- ./tests.sh

dependencies:

- build_job

Add Caching

cache:

paths:

- build/

Use Runner Tags

tags:

- docker

Common GitLab Runner Commands