<a id="tutorial-getting-started"></a>

# 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](https://charmhub.io/content-cache-k8s).
- Deploy [any-charm](https://charmhub.io/any-charm) as a backend application.
- Relate both.
- Relate `content-cache-k8s` to [Ingress](https://kubernetes.io/docs/concepts/services-networking/ingress/#what-is-ingress) by using [NGINX Ingress Integrator](https://charmhub.io/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

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- Juju 3 installed.

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- Juju controller and model created.
- NGINX Ingress Controller. If you’re using [MicroK8s](https://microk8s.io/), this can be done by running the command `microk8s enable ingress`. For more details, see [Add-on: Ingress](https://microk8s.io/docs/addon-ingress).

For more information about how to install Juju, see [Get started with Juju](https://canonical.com/juju/docs/juju-cli/3.6/tutorial/#tutorial).

### 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:

```bash
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](https://canonical.com/juju/docs/juju-cli/3.6/reference/juju-cli/list-of-juju-cli-commands/status/#command-juju-status) to see the current status of the deployment. In the Unit list, you can see that Content-cache-k8s is blocked:

```bash
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](https://canonical.com/juju/docs/juju-cli/3.6/reference/juju-cli/list-of-juju-cli-commands/integrate/#command-juju-integrate) command:

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

```

Run `juju status` to see that the message has changed:

```bash
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?](https://canonical.com/juju/docs/nginx-ingress-integrator-charm/latest/explanation/what-is-ingress/#explanation-what-is-ingress).

Deploy the charm NGINX Ingress Integrator:

```bash
juju deploy nginx-ingress-integrator

```

If your cluster has [RBAC](https://kubernetes.io/docs/reference/access-authn-authz/rbac/) enabled, you’ll be prompted to run the following:

```bash
juju trust nginx-ingress-integrator --scope cluster

```

Run `juju status` to verify the deployment.

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

```bash
juju integrate content-cache-k8s nginx-ingress-integrator

```

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

```bash
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:

```sh
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:

```sh
juju run backend-app/0 rpc method=start_server

```

And try again:

```sh
curl http://127.0.0.1

```

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