GitOps Cookbook

Chapter 7. Argo CD

In the previous chapter, you learned about Tekton and other engines such as GitHub Actions to implement the continuous integration (CI) part of a project.

Although CI is important because it’s where you build the application and check that nothing has been broken (running unit tests, component tests, etc.), there is still a missing part: how to deploy this application to an environment (a Kubernetes cluster) using the GitOps methodology and not creating a script running kubectl/helm commands.

As Daniel Bryant puts it, “If you weren’t using SSH in the past to deploy your application in production, don’t use kubectl to do it in Kubernetes.”

In this chapter, we’ll introduce you to Argo CD, a declarative, GitOps continuous delivery (CD) tool for Kubernetes. In the first part of the section, we’ll see the deployment of an application using Argo CD (Recipes 7.1 and 7.2).

Argo CD not only supports the deployment of plain Kubernetes manifests, but also the deployment of Kustomize projects (Recipe 7.3) and Helm projects (Recipe 7.4).

A typical operation done in Kubernetes is a rolling update to a new version of the container, and Argo CD integrates with another tool to make this process smooth (Recipe 7.5).

Delivering complex applications might require some orchestration on when and how the application must be deployed and released (Recipes 7.7 and 7.8).

We’ll see how to:

• Install and deploy the first application.

• Use automatic deployment and self-healing ...