@@ -5,10 +5,7 @@ description: "Learn how to use GitLab CI/CD, the GitLab built-in Continuous Inte
# GitLab Continuous Integration (GitLab CI/CD)
GitLab provides tools for continuously integrating and delivering code.
Within the [entire DevOps lifecycle](../README.md#the-entire-devops-lifecycle), GitLab CI/CD spans
the [Verify (CI)](../README.md#verify) and [Release (CD)](../README.md#release) stages.
**GitLab CI/CD** is GitLab's built-in tool for software development using the Continuous Methodology (Continuous Integration, Continuous Delivery, Continuous Deployment).
## Overview
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@@ -16,31 +13,13 @@ CI/CD is a vast area, so GitLab provides documentation for all levels of experti
| New to the concepts of CI and CD | For a high-level overview, see the [GitLab Continuous Integration & Delivery](https://about.gitlab.com/product/continuous-integration/) product page. |
| Familiar with the purpose of CI/CD | Delve into GitLab CI/CD by continuing down the page, starting with our [introduction](#introduction). |
| New to the concepts of CI and CD | For a high-level overview, read an [introduction to CI/CD with GitLab](introduction/index.md). |
| Familiar with GitLab CI/CD concepts | After getting familiar with GitLab CI/CD, let us walk you through a simple example in our [quick start guide](quick_start/README.md). |
| A GitLab CI/CD expert | Jump straight to our [`.gitlab.yml`](yaml/README.md) reference. |
## Introduction
The following introduces the process of continuous integration (CI) and continuous delivery (CD):
- New code is combined with existing code through a commit to a project's [repository](../user/project/repository/index.md).
- The newly combined code is sent to a CI [pipeline](pipelines.md) where:
- The code is [built](../user/project/pipelines/job_artifacts.md).
- Unit and integration tests are run over the built code.
- Assuming the build and tests are successful, a CD pipeline is triggered to allow for:
- Review using [Review Apps](review_apps/index.md).
- Deploying to configured [environments](environments.md).
The benefits of CI/CD are vast, allowing automation to be an integral part of your workflow for testing, building, deploying, and monitoring your code.
Because CI and CD with GitLab is broad topic with many possibilities, the rest of this section provides
links to topics and resources needed to make use of GitLab CI/CD.
NOTE: **Note:**
Within the [DevOps lifecycle](../README.md#the-entire-devops-lifecycle), GitLab CI/CD spans
the [Verify (CI)](../README.md#verify) and [Release (CD)](../README.md#release) stages.
## Essentials
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@@ -102,7 +81,8 @@ use of advanced features:
### GitLab Pages
GitLab CI/CD can be used to build and host static websites. For more information, see the
documentation on [GitLab Pages](../user/project/pages/index.md).
documentation on [GitLab Pages](../user/project/pages/index.md),
or dive right into the [CI/CD step-by-step guide for Pages](../user/project/pages/getting_started_part_four.md).
is also a further step beyond Continuous Integration, similar to
Continuous Delivery. The difference is that instead of deploying your
application manually, you set it to be deployed automatically. It does
not require human intervention at all to have your application
deployed.
## Introduction to GitLab CI/CD
GitLab CI/CD is a powerful tool built into GitLab that allows you
to apply all the continuous methods (Continuous Integration,
Delivery, and Deployment) to your software with no third-party
application or integration needed.
### How GitLab CI/CD works
To use GitLab CI/CD, all you need is an application codebase hosted in a
Git repository, and for your build, test, and deployment
scripts to be specified in a file called [`.gitlab-ci.yml`](../yaml/README.md),
located in the root path of your repository.
In this file, you can define the scripts you want to run, define include and
cache dependencies, choose what commands you want to run in sequence
and those you want to run in parallel, define where you want to
deploy your app, and choose if you want to run the script automatically
or if you want to trigger it manually. Once you're familiar with
GitLab CI/CD you can add more advanced steps into the configuration file.
To add scripts to that file, you'll need to organize them in a
sequence that suits your application and are in accordance with
the tests you wish to perform. To visualize the process, imagine
that all the scripts you add to the configuration file are the
same as the commands you run on a terminal in your computer.
Once you've added your `.gitlab-ci.yml` configuration file to your
repository, GitLab will detect it and run your scripts with the
tool called [GitLab Runner](https://docs.gitlab.com/runner/), which
works similarly to your terminal.
The scripts are grouped into **jobs**, and together they compose
a **pipeline**. A minimalist example of `.gitlab-ci.yml` file
could contain:
```yml
before_script:
-apt-get install rubygems ruby-dev -y
run-test:
script:
-ruby --version
```
The `before_script` attribute would install the dependencies
for your app before running anything, and a **job** called
`run-test` would print the Ruby version of the current system.
Both of them compose a **pipeline** triggered at every push
to any branch of the repository.
GitLab CI/CD not only executes the jobs you've
set, but also shows you what's happening during execution, as you
would see in your terminal:
You create the strategy for your app and GitLab runs the pipeline
for you according to what you've defined. Your pipeline status is also
displayed by GitLab:
At the end, if anything goes wrong, you can easily
[roll back](../environments.md#rolling-back-changes) all the changes:
### Basic CI/CD workflow
This is a very simple example for how GitLab CI/CD fits in a common
development workflow.
Assume that you have discussed a code implementation in an issue
and worked locally on your proposed changes. Once you push your
commits to a feature branch in a remote repository in GitLab,
the CI/CD pipeline set for your project is triggered. By doing
so, GitLab CI/CD:
- Runs automated scripts (sequential or parallel) to:
- Build and test your app.
- Deploy to a staging environment.
- Preview the changes per merge request with Review Apps, as you
would see in your `localhost`.
Once you're happy with your implementation:
- Get your code reviewed and approved.
- Merge the feature branch into the default branch.
- GitLab CI/CD deploys your changes automatically to a production environment.
- And finally, you and your team can easily roll it back if something goes wrong.
GitLab CI/CD is capable of a doing a lot more, but this workflow
exemplifies GitLab's ability to track the entire process,
without the need of any external tool to deliver your software.
And, most usefully, you can visualize all the steps through
the GitLab UI.
### Setting up GitLab CI/CD for the first time
To get started with GitLab CI/CD, you need to familiarize yourself
with the [`.gitlab-ci.yml`](../yaml/README.md) configuration file
syntax and with its attributes.
This document [introduces the concepts of GitLab CI/CD in the scope of GitLab Pages](../../user/project/pages/getting_started_part_four.md), for deploying static websites.
Although it's meant for users who want to write their own Pages
script from scratch, it also serves as an introduction to the setup process for GitLab CI/CD.
It covers the very first general steps of writing a CI/CD configuration
file, so we recommend you read through it to understand GitLab's CI/CD
logic, and learn how to write your own script (or tweak an
existing one) for any application.
For an deep view of GitLab's CI/CD configuration options, check the
[`.gitlab-ci.yml` full reference](../yaml/README.md).
### GitLab CI/CD feature set
- Easily set up your app's entire lifecycle with [Auto DevOps](../../topics/autodevops/index.md).
- Deploy static websites with [GitLab Pages](../../user/project/pages/index.md).
- Deploy your app to different [environments](../environments.md).
- Preview changes per merge request with [Review Apps](../review_apps/index.md).
- Develop secure and private Docker images with [Container Registry](../../user/project/container_registry.md).
- Install your own [GitLab Runner](https://docs.gitlab.com/runner/).
- Check for app vulnerabilities with [Security Test reports](https://docs.gitlab.com/ee/user/project/merge_requests/#security-reports-ultimate). **[ULTIMATE]**
To see all CI/CD features, navigate back to the [CI/CD index](../README.md).
