ArgoCD Exercise

Prereqs

Make sure you have gone through the Kubernetes cluster setup prior to this guide. The docs for ArgoCD: https://argo-cd.readthedocs.io/en/stable/

Install ArgoCD

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

Accessing ArgoCD UI

Note: While you don't need to view the ArgoCD UI it does look pretty cool

In order to log in to the ArgoCD UI, run the following command

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

The previous command retrieved the generated password that will be used to log in to the UI with the user "admin" and the password was copied into your clipboard (courtesy of pbcopy)

In order to view the ArgoCD UI, run the following command:

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

This command allows us to view the ArgoCD UI by visiting http://localhost:8080 in our browswer.

Note: Your browser might complain about it being an "insecure" site, but this is because we have not configured the UI with proper SSL Certificates so proceed since we are not going to steal our own data

The UI should look like the below (at least on March 1st, 2022, it did)

Enter "admin" as the username and use what's in your clipboard (or run that command again) as the password

After logging in you the Applications Dashboard should look like the below The UI should look like the below (at least on March 1st, 2022, it did)

Wow so much nothing! Move on to the deploy step so we can actually see something interesting on this page

Deploying an application

In the guestbook-api-config directory, you will see two files. A deployment.yaml and a service.yaml, this is the end result of what will be created on Kubernetes. ArgoCD will do this by providing an Application CRD. The Application CRD is the Kubernetes resource object representing a deployed application instance in an environment. It is defined by two key pieces of information: a source and a destination.

See guestbook-application.yaml and read more: ArgoCD Application

Now that you understand what an Application is in ArgoCD terms, let's create one!

kubectl apply -f guestbook-application.yaml

Expected output

application.argoproj.io/guestbook created

So....guess what? Your app is up and running.

Don't believe me, check our your ArgoCD Dashboard

After clicking on the app in the dashboard, you can see what components that are getting created:

And finally, you can run one more command and see that the application is running as expected

kubectl port-forward svc/guestbook-ui -n guestbook 8000:80

Now visit http://localhost:8000 to see the guestbook app

So in summation, ArgoCD is really cool and this is a very basic exercise. There is more to learn and much more to do

Deploying an application of applications (app of apps)

Deploying an application of applications (app of apps)

Deploying a single app is cool, but who runs just one app anymore? 

ArgoCD actually allows us to deploy multiple apps by defining a single top level app. This paradigm is called "app of apps". App Of Apps

If you run the following command (that references the attached app-of-apps.application.yaml file)

kubectl apply -f app-of-apps.application.yaml

Expected output

application.argoproj.io/guestbook-apps created

Now if you visit the ArgoCD UI you will see that multiple apps were created

If you click on guestbook-apps, you can see the relationship of how this single app created the tree of other apps

Cleaning up the application can be done by running kubectl delete

kubectl delete -f guestbook-application.yaml

Coming soon

Yo dog, I heard you want ArgoCD so I ArgoCD'd your ArgoCD

https://argo-cd.readthedocs.io/en/stable/operator-manual/declarative-setup/#manage-argo-cd-using-argo-cd