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

Performing extended checks with conftest

Open Policy Agent (OPA) (https://www.openpolicyagent.org) is an engine that can validate objects prior to performing a change on them. Its main advantage lies in the fact that it doesn’t come with a predefined list of checks; instead, it supports extensible policies as they are based on rules created in the Rego language (https://www.openpolicyagent.org/docs/latest/policy-language/). You might have heard of OPA in conjunction with Kubernetes: that it can be used like an admission controller (a part usually handled by the Gatekeeper project: https://github.com/open-policy-agent/gatekeeper) in order to add a pre-validation of the objects you want to apply in a cluster. OPA is really successful at adding policy-as-code checks for Kubernetes, but it is more than that: it is an engine that can be run almost everywhere we have a runtime, including in our CI/CD pipelines.

For Kubernetes, you can create your own custom rules to be enforced...