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

Notifying the end user

To synchronize applications, Argo CD can work in two different ways. First, it can work manually so that a new commit to the GitOps repo will not have any direct effect unless you trigger the synchronization manually via the CLI, by using the UI, or by using an API call. The second mode, which I think is the most used one, is that after a push to the repo, Argo CD will start to automatically reconcile the cluster state so that it matches the one we declared.

The developers that performed the state changes are interested in the outcome of the reconciliation – they want to know if their microservices are up and running correctly or if they have some problems with the new configuration or the new container image.

Earlier, we learned how to monitor the synchronization process using Prometheus and the metrics Argo CD exposes for application health and synchronization status. However, there is another way we can notify development teams that their microservices...