Merge pull request #80 from rossf7/docs/cluster-infra-dev

docs: Add docs for cluster infra dev with tofu

docs/infrastructure/cluster-infra-development.md

@@ -0,0 +1,94 @@
+# Cluster infra development
+
+## Overview
+
+Our cluster runs on physical servers from Equinix Metal contributed to CNCF.
+
+- We use OpenTofu to manage the cluster infra and an S3 bucket from AWS to store the tofu state.
+- To manage components running in the cluster we use Flux.
+
+## Pre-Requisites
+
+- Install the [tofu](https://opentofu.org/docs/intro/install/) CLI
+- Fork the tooling repo https://github.com/cncf-tags/green-reviews-tooling
+- Get access to the `Green Reviews Cluster Dev` vault in the TAG ENV 1Password account (please post in the #tag-env-wg-green-reviews channel in CNCF Slack so we have tracking for your request) 
+
+## Setup
+
+- In a local copy of your fork change to the working directory
+
+```sh
+cd infrastructure/equinix-metal
+```
+
+- Set env vars for tofu from 1Password with AWS and Equinix credentials
+
+```sh
+export AWS_ACCESS_KEY_ID="*****"
+export AWS_SECRET_ACCESS_KEY="*****"
+export TF_VAR_equinix_auth_token="*****"
+export TF_VAR_equinix_project_id="*****"
+export TF_VAR_k3s_token="*****"
+```
+
+- Set env vars for your fork including a GitHub PAT for bootstrapping Flux
+
+```sh
+export TF_VAR_cluster_name="green-reviews-dev"
+export TF_VAR_flux_github_user="*** Your GitHub user ***"
+export TF_VAR_flux_github_repo="green-reviews-tooling"
+export TF_VAR_flux_github_token="*** Your GitHub PAT ***"
+export TF_VAR_flux_github_branch="*** Your branch ***"
+export TF_VAR_ssh_public_key="*** Your SSH public key ***"
+```
+
+- Check tofu workspaces
+
+```sh
+tofu workspace list
+
+  default
+* dev
+```
+
+- If the dev workspace doesn't exist create it.
+
+```sh
+tofu workspace new dev
+```
+
+- Ensure you are using the **dev** workspace
+
+```sh
+tofu workspace select dev
+```
+
+## Making changes
+
+Follow the usual tofu workflow. See [core workflow](https://opentofu.org/docs/intro/core-workflow/)
+for more details.
+
+- Make changes
+- Initialize tofu
+
+```sh
+tofu init
+```
+
+- Review changes
+
+```sh
+tofu plan
+```
+
+- Test changes - **make sure you are using dev workspace**
+
+```sh
+tofu apply
+```
+
+- Cleanup - **make sure you are using dev workspace**
+
+```sh
+tofu destroy
+```