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Migrating from CircleCI (FREE)
If you are currently using CircleCI, you can migrate your CI/CD pipelines to GitLab CI/CD, and start making use of all its powerful features. Check out our CircleCI vs GitLab comparison to see what's different.
We have collected several resources that you may find useful before starting to migrate.
The Quick Start Guide is a good overview of how GitLab CI/CD works. You may also be interested in Auto DevOps which can be used to build, test, and deploy your applications with little to no configuration needed at all.
For advanced CI/CD teams, custom project templates can enable the reuse of pipeline configurations.
If you have questions that are not answered here, the GitLab community forum can be a great resource.
config.yml
vs .gitlab-ci.yml
CircleCI's config.yml
configuration file defines scripts, jobs, and workflows (known as "stages" in GitLab). In GitLab, a similar approach is used with a .gitlab-ci.yml
file in the root directory of your repository.
Jobs
In CircleCI, jobs are a collection of steps to perform a specific task. In GitLab, jobs are also a fundamental element in the configuration file. The checkout
keyword is not necessary in GitLab CI/CD as the repository is automatically fetched.
CircleCI example job definition:
jobs:
job1:
steps:
- checkout
- run: "execute-script-for-job1"
Example of the same job definition in GitLab CI/CD:
job1:
script: "execute-script-for-job1"
Docker image definition
CircleCI defines images at the job level, which is also supported by GitLab CI/CD. Additionally, GitLab CI/CD supports setting this globally to be used by all jobs that don't have image
defined.
CircleCI example image definition:
jobs:
job1:
docker:
- image: ruby:2.6
Example of the same image definition in GitLab CI/CD:
job1:
image: ruby:2.6
Workflows
CircleCI determines the run order for jobs with workflows
. This is also used to determine concurrent, sequential, scheduled, or manual runs. The equivalent function in GitLab CI/CD is called stages. Jobs on the same stage run in parallel, and only run after previous stages complete. Execution of the next stage is skipped when a job fails by default, but this can be allowed to continue even after a failed job.
See the Pipeline Architecture Overview for guidance on different types of pipelines that you can use. Pipelines can be tailored to meet your needs, such as for a large complex project or a monorepo with independent defined components.
Parallel and sequential job execution
The following examples show how jobs can run in parallel, or sequentially:
job1
andjob2
run in parallel (in thebuild
stage for GitLab CI/CD).job3
runs only afterjob1
andjob2
complete successfully (in thetest
stage).job4
runs only afterjob3
completes successfully (in thedeploy
stage).
CircleCI example with workflows
:
version: 2
jobs:
job1:
steps:
- checkout
- run: make build dependencies
job2:
steps:
- run: make build artifacts
job3:
steps:
- run: make test
job4:
steps:
- run: make deploy
workflows:
version: 2
jobs:
- job1
- job2
- job3:
requires:
- job1
- job2
- job4:
requires:
- job3
Example of the same workflow as stages
in GitLab CI/CD:
stages:
- build
- test
- deploy
job1:
stage: build
script: make build dependencies
job2:
stage: build
script: make build artifacts
job3:
stage: test
script: make test
job4:
stage: deploy
script: make deploy
environment: production
Scheduled run
GitLab CI/CD has an easy to use UI to schedule pipelines. Also, rules can be used to determine if jobs should be included or excluded from a scheduled pipeline.
CircleCI example of a scheduled workflow:
commit-workflow:
jobs:
- build
scheduled-workflow:
triggers:
- schedule:
cron: "0 1 * * *"
filters:
branches:
only: try-schedule-workflow
jobs:
- build
Example of the same scheduled pipeline using rules
in GitLab CI/CD:
job1:
script:
- make build
rules:
- if: $CI_PIPELINE_SOURCE == "schedule" && $CI_COMMIT_REF_NAME == "try-schedule-workflow"
After the pipeline configuration is saved, you configure the cron schedule in the GitLab UI, and can enable or disable schedules in the UI as well.
Manual run
CircleCI example of a manual workflow:
release-branch-workflow:
jobs:
- build
- testing:
requires:
- build
- deploy:
type: approval
requires:
- testing
Example of the same workflow using when: manual
in GitLab CI/CD:
deploy_prod:
stage: deploy
script:
- echo "Deploy to production server"
when: manual
environment: production
Filter job by branch
Rules are a mechanism to determine if the job runs for a specific branch.
CircleCI example of a job filtered by branch:
jobs:
deploy:
branches:
only:
- main
- /rc-.*/
Example of the same workflow using rules
in GitLab CI/CD:
deploy:
stage: deploy
script:
- echo "Deploy job"
rules:
- if: $CI_COMMIT_BRANCH == "main" || $CI_COMMIT_BRANCH =~ /^rc-/
environment: production
Caching
GitLab provides a caching mechanism to speed up build times for your jobs by reusing previously downloaded dependencies. It's important to know the different between cache and artifacts to make the best use of these features.
CircleCI example of a job using a cache:
jobs:
job1:
steps:
- restore_cache:
key: source-v1-< .Revision >
- checkout
- run: npm install
- save_cache:
key: source-v1-< .Revision >
paths:
- "node_modules"
Example of the same pipeline using cache
in GitLab CI/CD:
image: node:latest
# Cache modules in between jobs
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
Contexts and variables
CircleCI provides Contexts to securely pass environment variables across project pipelines. In GitLab, a Group can be created to assemble related projects together. At the group level, CI/CD variables can be stored outside the individual projects, and securely passed into pipelines across multiple projects.
Orbs
There are two GitLab issues open addressing CircleCI Orbs and how GitLab can achieve similar functionality.
Build environments
CircleCI offers executors
as the underlying technology to run a specific job. In GitLab, this is done by runners.
The following environments are supported:
Self-managed runners:
- Linux
- Windows
- macOS
GitLab.com shared runners:
Machine and specific build environments
Tags can be used to run jobs on different platforms, by telling GitLab which runners should run the jobs.
CircleCI example of a job running on a specific environment:
jobs:
ubuntuJob:
machine:
image: ubuntu-1604:201903-01
steps:
- checkout
- run: echo "Hello, $USER!"
osxJob:
macos:
xcode: 11.3.0
steps:
- checkout
- run: echo "Hello, $USER!"
Example of the same job using tags
in GitLab CI/CD:
windows job:
stage:
- build
tags:
- windows
script:
- echo Hello, %USERNAME%!
osx job:
stage:
- build
tags:
- osx
script:
- echo "Hello, $USER!"