SRE@Kyndryl

SRE Public Labs - GitOps Sim

• Version: 0.1.0
• License: MIT

Architecture

// TODO

Learning objectives

• Learn how to deploy an app using GitOps approach

• Learn how use Argo CD as a GitOps platform

Pre-requisite knowledge

• Familiarity with Kubernetes

• Basic notions on Node.js (JavaScript) programming language

• Good understanding of YAML (Yet Another Markup Language)

Kubernetes cluster

This lab runs on any K8s cluster with few adjusts on the ingresses, we recommend using a free trial account on Google Cloud Platform. You can create one through this documentation. You can download and install the Google CLI gcloud by checking this document.

In case you use a GCP account for this lab, we provided the Google Kubernetes Engine (GKE) recommended configuration below:

• GKE Configuration

Parameter	Value
GKE mode	Standard with static K8s version
Location type	Zonal
Release channel	None
Kubernetes version	v1.24.6-gke.1500
Number of nodes	3
Machine type	e2-medium
Image type	cos_containerd

• GKE cluster creation

You can create a K8s cluster for this lab with the following commands:

gcloud auth login
gcloud container clusters create gitops-sim --no-enable-autoupgrade --enable-service-externalips \
 --enable-kubernetes-alpha --region=<your_closest_region> --cluster-version= v1.24.6-gke.1500 \
 --machine-type=e2-medium --monitoring=NONE

• kubectl configuration

You can configure your local kubectl environment and credentials with the following command:

gcloud container clusters get-credentials gitops-sim \
 --zone <your_closest_zone> --project <your_project_id>

Lab Contents

• Argo CD

Argo CD is installed through its default K8s manifest file located here.

• Node.js API app

There's a dummy Node.js API available as K8s manifest files here. It points to a public Docker image located at the Docker Hub.

image: rod4n4m1/node-api:0.1.2

• Folder contents: argocd

File / folder	Description
deploy.sh	Automation script to deploy latest stable Argo CD release to a K8s cluster
ingress.yaml	A K8s ingress for Argo CD in case one is needed
install.sh	Automation script to create an Argo CD app and deploy the Node.js API using GitOps approach to a K8s cluster
README.d	This file
process.env	Example of environmental variables definition to configure the deploy.sh script

Installation

• Install Argo CD

This automation script will deploy the latest stable Argo CD release to a K8s cluster under the argocd namespace.

cd argo-cd
./install.sh

• More information here

Configuration

• Change environmental variables accordingly

• File: process.env

#!/bin/bash

export ARGOCD_ADMIN_NAME="admin"
export APP_NAME="simple-node-api"
export APP_REPO_URL="https://github.com/kyndryl-open-source/gitops-app-examples.git"
export APP_REPO_PATH="simple-node-api"

• You can fork the above repository if you want to modify the application image and version. Under a GitOps approach, all changes to the application or infrastructure is made to the GitHub repository and not on the K8s cluster directly.

Deployment

• Deploy a Simple Node.js API

This will deploy a K8s app as an Argo CD app to the cluster where it's running. An Argo CD app synchronizes with IaC and app manifest files in a GitHub repo.

cd argo-cd
./deploy.sh

Usage

• You can access the Argo CD console by checking the LoadBalancer service IP address:

kubectl get svc -n argocd

• Open a browser with the following ULR: http://<load_balancer_ip>

• Log into the console using the admin username and its initial password

• The deploy.sh script have created an Argo CD app that synchronizes with a GitHub repo

• If you have forked the application repository, you can change the image and version, then resynchronize the Argo CD app

End of document