## Amazon EKS cluser management with Crossplane and Argo CD

This Git repository contains software artifacts to deploy [Crossplane](https://crossplane.io/) server and [Argo CD](https://argoproj.github.io/argo-cd/) to an existing Amazon EKS cluster and then leverage the GitOps workflow to manage both provisioning a remote EKS cluster with Crossplane and subsequently manage application deployments to it using Argo CD. Please refer to the [accompanying blog post](https://aws.amazon.com/blogs/containers/gitops-model-for-provisioning-and-bootstrapping-amazon-eks-clusters-using-crossplane-and-argo-cd/) for details about how this works.

<img class="wp-image-1960 size-full" src="images/Deployment-Architecture.png" alt="Deployment architecture"/>

### Solution overview

Here’s the high level overview of the solution architecture. 
- Start off with an Amazon EKS cluster that was created using any one of the approaches outlined [here](https://docs.aws.amazon.com/eks/latest/userguide/create-cluster.html)
- Install Argo CD on this cluster to manage all deployment tasks and point it to a Git repository containing the deployment artifacts
- Deploy Crossplane components that are needed to manage the lifecycle of AWS managed service resources  
- Deploy Crossplane-specific custom resources to provision an Amazon EKS cluster  
- Deploy a set of workloads to the new cluster  

The goal is to manage all of these tasks in a declarative style based on the [GitOps](https://www.weave.works/blog/what-is-gitops-really) approach.

### Deployment overview

#### Imperative approach
The script [crossplane.sh](https://github.com/aws-samples/eks-gitops-crossplane-argocd/blob/main/crossplane.sh) outlines the CLI commands used in this implementation to install Crossplane to a management EKS cluster and then provision a workload EKS cluster. The implementation uses Crossplane's [Composition](https://crossplane.io/docs/v1.4/concepts/composition.html)  and [CompositeResourceDefinition](https://crossplane.io/docs/v1.4/concepts/composition.html) to create a Crossplane [Configuration package](https://crossplane.io/docs/v1.4/concepts/packages.html#configuration-packages) that will provision the complete infrastructure for setting up an EKS cluster - VPC, subnets, internet gateway, NAT gateways, route tables, and the EKS cluster with a managed node group. The figure below shows the relationship between various Crossplane custom resources used in this Configuration package and the set of AWS managed resources that they provision.

<img class="wp-image-1960 size-full" src="images/Component-Relationship.png" alt="Component Relationship"/>

#### Declarative approach
The script [argocd.sh](https://github.com/aws-samples/eks-gitops-crossplane-argocd/blob/main/argocd.sh) outlines the steps involved in installing Argo CD on the management EKS cluster and then leveraging the GitOps workflow in Argo CD to manage both provisioning and management of a remote workload cluster.

## Security
See [CONTRIBUTING](CONTRIBUTING.md#security-issue-notifications) for more information.

## License
This library is licensed under the MIT-0 License. See the LICENSE file.