Basic deployment of the content-cache-k8s charm

In this tutorial, we will deploy and integrate the Content Cache K8s charm using Juju.

What you’ll do

• Deploy the Content-cache-k8s charm.
• Deploy any-charm as a backend application.
• Relate both.
• Relate content-cache-k8s to Ingress by using NGINX Ingress Integrator.

Through the process, you’ll inspect the Kubernetes resources created, verify the workload state and assign the Content-cache-k8s to serve your any-app instance.

What you’ll need

• Juju 3 installed.

• Juju controller and model created.
• NGINX Ingress Controller. If you’re using MicroK8s, this can be done by running the command microk8s enable ingress. For more details, see Add-on: Ingress.

For more information about how to install Juju, see Get started with Juju.

Deploy the content-cache-k8s charm

Since Content-cache is meant to serve as cache for another charm, we’ll use any-charm as an example.

Deploy the charms:

juju deploy content-cache-k8s
juju deploy any-charm backend-app --channel beta --config src-overwrite="$(curl -L https://github.com/canonical/content-cache-k8s-operator/releases/download/rev62/any_app_backend_src.json))"

Run juju status to see the current status of the deployment. In the Unit list, you can see that Content-cache-k8s is blocked:

content-cache-k8s/0*  blocked   idle   10.1.97.227         Required config(s) empty: backend, site
backend-app/0*        active    idle   10.1.97.193

This is because the Content-cache-k8s charm isn’t integrated with our backend-app yet.

Relate to the backend application

Provide the relation between content-cache-k8s and backend-app by running the following juju integrate command:

juju integrate content-cache-k8s:nginx-proxy backend-app

Run juju status to see that the message has changed:

content-cache-k8s/0*  active    idle   10.1.97.227         Ready
backend-app/0*        active    idle   10.1.97.193

Note: nginx-proxy is the name of the relation. You can run juju info content-cache-k8s to check what are the relation names provided by the Content-cache-k8s application and juju status --relations to see the relations currently established in the model.

The deployment finishes when the status shows “Active”.

Relate to ingress by using NGINX ingress integrator

The NGINX Ingress Integrator charm can deploy and manage external access to HTTP/HTTPS services in a Kubernetes cluster.

If you want to make Content-cache-k8s charm available to external clients, you need to deploy the NGINX Ingress Integrator charm and integrate Content-cache-k8s with it.

See more details in What is Ingress?.

Deploy the charm NGINX Ingress Integrator:

juju deploy nginx-ingress-integrator

If your cluster has RBAC enabled, you’ll be prompted to run the following:

juju trust nginx-ingress-integrator --scope cluster

Run juju status to verify the deployment.

Provide integration between Content-cache-k8s and NGINX Ingress Integrator:

juju relate content-cache-k8s nginx-ingress-integrator

Run juju status to see the same Ingress IP in the nginx-ingress-integrator message:

nginx-ingress-integrator                                active      1  nginx-ingress-integrator  stable    45  10.152.183.233  no       Ingress IP(s): 127.0.0.1, Service IP(s): 10.152.183.66

Test the whole thing

The hostname of the backend application is backend-app.

You can access it through your ingress IP with the following command:

curl http://127.0.0.1

It should return a 404 as the backend-app is not answering to requests yet.

Start the web server with:

juju run backend-app/0 rpc method=start_server

And try again:

curl http://127.0.0.1

This time you should get a HTML page containing: ok.