GitLab CI/CD is the continuous integration and continuous deployment system built into GitLab. It builds, tests and deploys applications through pipelines defined in YAML files.
What sets it apart:
Pipelines live next to the code, so there is no separate CI product to connect.
The whole pipeline is configuration as code, in .gitlab-ci.yml.
A built-in container registry stores Docker images next to the code.
Auto DevOps can create a pipeline automatically for common frameworks.
The same platform also covers issue tracking and code review, and it includes monitoring.
Jenkins is a separate server that needs plugins and setup, and GitHub Actions works only with GitHub repositories. GitLab bundles CI/CD with the rest of the DevOps workflow.
Rewriting in plainer words…
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