GitLab is a web-based DevOps lifecycle tool that provides a Git-repository,wiki, issue-tracking and continuous integration/continuous deployment pipeline features and its “open-source ” .
It makes the release process much more easier and the developers can run and check the live build logs in same web application without opening Jenkins , also has issue tracking and wiki so tracking bugs and tasks along with documentation are available in the same place and it’s free if you opt for the community edition and use it on your own infrastructure or else it would come with costs if you use their Infrastructure .
I will be discussing about CI/CD here
This is how the CI/CD workflow looks like in general and we can use gitlab to simplify the process
GitLab CI/CD Architecture
We have the Gitlab Server which is a web application provides the UI and stores all the repositories and we have the runners in gitlab where the builds are done.
You can refer to this link for more details on usage of Gitlab CI
https://about.gitlab.com/stages-devops-lifecycle/continuous-integration/
fork&exec 