Book Image

Argo CD in Practice

By : Liviu Costea, Spiros Economakis
Book Image

Argo CD in Practice

By: Liviu Costea, Spiros Economakis

Overview of this book

GitOps follows the practices of infrastructure as code (IaC), allowing developers to use their day-to-day tools and practices such as source control and pull requests to manage apps. With this book, you’ll understand how to apply GitOps bootstrap clusters in a repeatable manner, build CD pipelines for cloud-native apps running on Kubernetes, and minimize the failure of deployments. You’ll start by installing Argo CD in a cluster, setting up user access using single sign-on, performing declarative configuration changes, and enabling observability and disaster recovery. Once you have a production-ready setup of Argo CD, you’ll explore how CD pipelines can be built using the pull method, how that increases security, and how the reconciliation process occurs when multi-cluster scenarios are involved. Next, you’ll go through the common troubleshooting scenarios, from installation to day-to-day operations, and learn how performance can be improved. Later, you’ll explore the tools that can be used to parse the YAML you write for deploying apps. You can then check if it is valid for new versions of Kubernetes, verify if it has any security or compliance misconfigurations, and that it follows the best practices for cloud-native apps running on Kubernetes. By the end of this book, you’ll be able to build a real-world CD pipeline using Argo CD.
Table of Contents (15 chapters)
1
Part 1: The Fundamentals of GitOps and Argo CD
4
Part 2: Argo CD as a Site Reliability Engineer
7
Part 3: Argo CD in Production

Explaining architecture

In this section we will describe in depth the Architecture of Argo CD and we will make a deep dive in the core components of Argo CD. In the end we will run Argo CD in a local K8s cluster and run some examples to get a better practical experience with it.

Architectural overview

The Argo CD core component has been implemented as a Kubernetes controller, so before diving into each component individually we need to understand how a Kubernetes controller works.

Kubernetes controllers in practice they observe the state of the cluster and then they apply or request changes if it’s needed. So, in practice, the controller will try to keep the current cluster state similar to the desired state. A controller observes a Kubernetes resource object – at least one – and this has a spec field that represents the desired state.

Core components of Argo CD

Argo CD is a set of various components and tools. It’s time to explore in detail and learn about...