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

Synchronization principles

The sync phase of Argo CD is one of the most important operations and can become powerful if you use Resource hooks and Sync waves. This section will explain in detail these operations and you can see the unlimited power it can give you in a real environment.

Resource hooks

As we described in a previous section, sync is the phase for moving an application to the target state which happens by applying the changes in the Kubernetes cluster and this operation is executed by Argo CD in a number of steps. The phases of sync are as follows:

  • Pre-sync
  • Sync
  • Post-sync

These are called resource hooks which give us the power to run any other operation before, during or after the sync phase.

  • Using a PreSync hook to perform any action which needed to be done before the Sync phase. A typical example is database migration as we need to run first the migrations.
  • Using Skip indicates to Argo CD to skip the application of the manifest.
  • Using a Sync hook to orchestrate a complex...