Note: GitHub-hosted runners are not currently supported on GitHub Enterprise Server. You can see more information about planned future support on the GitHub public roadmap.
Introduction
GitLab CI/CD and GitHub Actions both allow you to create workflows that automatically build, test, publish, release, and deploy code. GitLab CI/CD and GitHub Actions share some similarities in workflow configuration:
- Workflow configuration files are written in YAML and are stored in the code's repository.
- Workflows include one or more jobs.
- Jobs include one or more steps or individual commands.
- Jobs can run on either managed or self-hosted machines.
There are a few differences, and this guide will show you the important differences so that you can migrate your workflow to GitHub Actions.
Jobs
Jobs in GitLab CI/CD are very similar to jobs in GitHub Actions. In both systems, jobs have the following characteristics:
- Jobs contain a series of steps or scripts that run sequentially.
- Jobs can run on separate machines or in separate containers.
- Jobs run in parallel by default, but can be configured to run sequentially.
You can run a script or a shell command in a job. In GitLab CI/CD, script steps are specified using the script
key. In GitHub Actions, all scripts are specified using the run
key.
Below is an example of the syntax for each system.
GitLab CI/CD syntax for jobs
job1:
variables:
GIT_CHECKOUT: "true"
script:
- echo "Run your script here"
GitHub Actions syntax for jobs
jobs:
job1:
steps:
- uses: actions/checkout@v4
- run: echo "Run your script here"
Runners
Runners are machines on which the jobs run. Both GitLab CI/CD and GitHub Actions offer managed and self-hosted variants of runners. In GitLab CI/CD, tags
are used to run jobs on different platforms, while in GitHub Actions it is done with the runs-on
key.
Below is an example of the syntax for each system.
GitLab CI/CD syntax for runners
windows_job:
tags:
- windows
script:
- echo Hello, %USERNAME%!
linux_job:
tags:
- linux
script:
- echo "Hello, $USER!"
GitHub Actions syntax for runners
windows_job:
runs-on: windows-latest
steps:
- run: echo Hello, %USERNAME%!
linux_job:
runs-on: ubuntu-latest
steps:
- run: echo "Hello, $USER!"
For more information, see "Workflow syntax for GitHub Actions."
Docker images
Both GitLab CI/CD and GitHub Actions support running jobs in a Docker image. In GitLab CI/CD, Docker images are defined with an image
key, while in GitHub Actions it is done with the container
key.
Below is an example of the syntax for each system.
GitLab CI/CD syntax for Docker images
my_job:
image: node:10.16-jessie
GitHub Actions syntax for Docker images
jobs:
my_job:
container: node:10.16-jessie
For more information, see "Workflow syntax for GitHub Actions."
Condition and expression syntax
GitLab CI/CD uses rules
to determine if a job will run for a specific condition. GitHub Actions uses the if
keyword to prevent a job from running unless a condition is met.
Below is an example of the syntax for each system.
GitLab CI/CD syntax for conditions and expressions
deploy_prod:
stage: deploy
script:
- echo "Deploy to production server"
rules:
- if: '$CI_COMMIT_BRANCH == "master"'
GitHub Actions syntax for conditions and expressions
jobs:
deploy_prod:
if: contains( github.ref, 'master')
runs-on: ubuntu-latest
steps:
- run: echo "Deploy to production server"
For more information, see "Expressions."
Dependencies between Jobs
Both GitLab CI/CD and GitHub Actions allow you to set dependencies for a job. In both systems, jobs run in parallel by default, but job dependencies in GitHub Actions can be specified explicitly with the needs
key. GitLab CI/CD also has a concept of stages
, where jobs in a stage run concurrently, but the next stage will start when all the jobs in the previous stage have completed. You can recreate this scenario in GitHub Actions with the needs
key.
Below is an example of the syntax for each system. The workflows start with two jobs named build_a
and build_b
running in parallel, and when those jobs complete, another job called test_ab
will run. Finally, when test_ab
completes, the deploy_ab
job will run.
GitLab CI/CD syntax for dependencies between jobs
stages:
- build
- test
- deploy
build_a:
stage: build
script:
- echo "This job will run first."
build_b:
stage: build
script:
- echo "This job will run first, in parallel with build_a."
test_ab:
stage: test
script:
- echo "This job will run after build_a and build_b have finished."
deploy_ab:
stage: deploy
script:
- echo "This job will run after test_ab is complete"
GitHub Actions syntax for dependencies between jobs
jobs:
build_a:
runs-on: ubuntu-latest
steps:
- run: echo "This job will be run first."
build_b:
runs-on: ubuntu-latest
steps:
- run: echo "This job will be run first, in parallel with build_a"
test_ab:
runs-on: ubuntu-latest
needs: [build_a,build_b]
steps:
- run: echo "This job will run after build_a and build_b have finished"
deploy_ab:
runs-on: ubuntu-latest
needs: [test_ab]
steps:
- run: echo "This job will run after test_ab is complete"
For more information, see "Workflow syntax for GitHub Actions."
Scheduling workflows
Both GitLab CI/CD and GitHub Actions allow you to run workflows at a specific interval. In GitLab CI/CD, pipeline schedules are configured with the UI, while in GitHub Actions you can trigger a workflow on a scheduled interval with the "on" key.
For more information, see "Events that trigger workflows."
Variables and secrets
GitLab CI/CD and GitHub Actions support setting variables in the pipeline or workflow configuration file, and creating secrets using the GitLab or GitHub Enterprise Server UI.
For more information, see "Variables" and "Using secrets in GitHub Actions."
Caching
GitLab CI/CD and GitHub Actions provide a method in the configuration file to manually cache workflow files.
Below is an example of the syntax for each system.
GitLab CI/CD syntax for caching
image: node:latest
cache:
key: $CI_COMMIT_REF_SLUG
paths:
- .npm/
before_script:
- npm ci --cache .npm --prefer-offline
test_async:
script:
- node ./specs/start.js ./specs/async.spec.js
GitHub Actions syntax for caching
jobs:
test_async:
runs-on: ubuntu-latest
steps:
- name: Cache node modules
uses: actions/cache@v3
with:
path: ~/.npm
key: v1-npm-deps-${{ hashFiles('**/package-lock.json') }}
restore-keys: v1-npm-deps-
Artifacts
Both GitLab CI/CD and GitHub Actions can upload files and directories created by a job as artifacts. In GitHub Actions, artifacts can be used to persist data across multiple jobs.
Below is an example of the syntax for each system.
GitLab CI/CD syntax for artifacts
script:
artifacts:
paths:
- math-homework.txt
GitHub Actions syntax for artifacts
- name: Upload math result for job 1
uses: actions/upload-artifact@v3
with:
name: homework
path: math-homework.txt
For more information, see "Storing workflow data as artifacts."
Databases and service containers
Both systems enable you to include additional containers for databases, caching, or other dependencies.
In GitLab CI/CD, a container for the job is specified with the image
key, while GitHub Actions uses the container
key. In both systems, additional service containers are specified with the services
key.
Below is an example of the syntax for each system.
GitLab CI/CD syntax for databases and service containers
container-job:
variables:
POSTGRES_PASSWORD: postgres
# The hostname used to communicate with the
# PostgreSQL service container
POSTGRES_HOST: postgres
# The default PostgreSQL port
POSTGRES_PORT: 5432
image: node:10.18-jessie
services:
- postgres
script:
# Performs a clean installation of all dependencies
# in the `package.json` file
- npm ci
# Runs a script that creates a PostgreSQL client,
# populates the client with data, and retrieves data
- node client.js
tags:
- docker
GitHub Actions syntax for databases and service containers
jobs:
container-job:
runs-on: ubuntu-latest
container: node:10.18-jessie
services:
postgres:
image: postgres
env:
POSTGRES_PASSWORD: postgres
steps:
- name: Check out repository code
uses: actions/checkout@v4
# Performs a clean installation of all dependencies
# in the `package.json` file
- name: Install dependencies
run: npm ci
- name: Connect to PostgreSQL
# Runs a script that creates a PostgreSQL client,
# populates the client with data, and retrieves data
run: node client.js
env:
# The hostname used to communicate with the
# PostgreSQL service container
POSTGRES_HOST: postgres
# The default PostgreSQL port
POSTGRES_PORT: 5432
For more information, see "About service containers."