Argocd

Prerequisite: [EKS Terragrunt](https://www.notion.so/EKS-Terragrunt-30d3205f20be8048a6eddd6450e4c8e4?pvs=21) 

## Overview

Here's how we will have ArgoCD available for internal teams:

1. Create a hosted zone for the subdomain in Route 53. It will be the
authoritative DNS zone for our subdomain, where all DNS records for
it will live. It outputs 4 name servers.
2. ⚠️ Manual step — Add those 4 name servers to our parent domain as NS
records in Namecheap. This delegates authority for the subdomain to
Route 53.
3. Use AWS Certificate Manager (ACM) to issue a TLS certificate for the
subdomain. ACM validates we own the domain by checking a CNAME record
we add to the hosted zone.

1. Install the AWS Load Balancer Controller (LBC) into the cluster. When
we create a k8s Ingress for ArgoCD, it provisions an Application Load Balancer (ALB) that uses the
ACM certificate to serve HTTPS traffic, and Route 53 is updated with
an Alias A record pointing the subdomain to the ALB.
2. Install the ExternalDNS controller that will update our DNS provider when we'll create an Ingress configuration (i.e it'll add the ALB hostname as an alias record to our subdomain).
3. Install ArgoCD will Helm with an Ingress to ALB.

## Route 53 Zone and ACM

To expose the ArgoCD UI publicly, we need a domain name backed by a valid
TLS certificate.

We'll use AWS Route 53 as a DNS service.

First, we'll create a subdomain on our existing domain. (If you don't have your own domain, you'll need to register one).

Then, we'll delegate DNS for our subdomain to Route53 by following the  https://docs.aws.amazon.com/Route53/latest/DeveloperGuide/CreatingNewSubdomain.html documentation.

Let's create a Route 53 hosted zone: