What Is Argo CD?

Argo CD is an open-source tool designed to support the GitOps workflow for deploying applications on Kubernetes. Argo CD is applied in the CD (Continuous Delivery) step of the CI/CD flow — this is the step where we deploy the application to the server environment.

Argo CD uses Git repositories as the primary source of truth to determine the desired application state, which is why it’s called a GitOps tool. In this series we use Argo CD to deploy the Microservice Book Info application below.

Book Info microservices

In this first post, we’ll learn how to install Argo CD and use the simplest way to deploy the Book Info application.

Installing Argo CD

Create a namespace for argocd and install it:

kubectl create namespace argocd
kubectl apply -n argocd --server-side -f https://raw.githubusercontent.com/argoproj/argo-cd/stable/manifests/install.yaml

Check that the installation succeeded:

kubectl get pods -n argocd

NAME                                                READY   STATUS    RESTARTS   AGE
argocd-application-controller-0                     1/1     Running   0          3m39s
argocd-applicationset-controller-744b76d7fd-xgk2d   1/1     Running   0          3m39s
argocd-dex-server-5bf5dbc64d-w8vdx                  1/1     Running   0          3m39s
argocd-notifications-controller-84f5bf6896-5mdbg    1/1     Running   0          3m39s
argocd-redis-74b8999f94-zmm5b                       1/1     Running   0          3m39s
argocd-repo-server-57f4899557-vxcrf                 1/1     Running   0          3m39s
argocd-server-7bc7b97977-nclk6                      1/1     Running   0          3m39s

Install the Argo CD CLI to interact with Argo CD. On Mac, Linux, or WSL, run:

brew install argocd

For Windows, see the CLI installation documentation. Access the Argo CD UI:

kubectl port-forward svc/argocd-server -n argocd 8080:443

Because we’re running on localhost, the website reports “unsafe”; click “proceed to localhost (unsafe)”:

Unsafe warning

The login UI:

Login UI

The default Argo CD account is admin. To get the password, run:

kubectl -n argocd get secret argocd-initial-admin-secret -o jsonpath="{.data.password}" | base64 -d

The UI after logging into Argo CD:

Argo CD dashboard

Deploying the Book Info Application

Book Info consists of the following services:

  • Products Service
  • Details Service
  • Reviews Service
  • Ratings Service

To deploy an application on Argo CD, we need to create an Application (explained in detail in the next post). Click the + New App button in the UI.

New App

Enter bookinfo as the application name, choose default for the project, and set the sync policy to Automatic. Leave the SYNC OPTIONS at their defaults for now.

App general settings

The Repository URL field is where we connect to Git, which holds the Kubernetes resource files we want to deploy. Use this repo devops-vn-blog — the Book Info manifests live under _resource/argocd-series/01-getting-started/bookinfo. It’s a public repo that anyone can access; in the next post I’ll show how to connect to a private repo. For the Path, enter _resource/argocd-series/01-getting-started/bookinfo:

Repository URL and path

For Destination, enter https://kubernetes.default.svc and choose the namespace to deploy to — mine is default.

Destination

Click the Create button.

Create

Wait for Argo CD to deploy the application.

Deploying

Once the status changes to synced, the bookinfo application has been deployed to the Kubernetes environment successfully. Click on the app.

Synced

The services we defined in YAML files and stored in Git have been deployed to Kubernetes by Argo CD. To check, open the Products page:

kubectl port-forward svc/products 9080:9080

Products page

In this post, we successfully deployed the Book Info microservice application the simple way. In the next post, we’ll go deeper into Argo CD concepts and apply them to deploy applications more professionally and effectively.