Add Ingress overlay to access Catalog contents outside of the cluster

Signed-off-by: Rashmi Gottipati <chowdary.grashmi@gmail.com>

docs/fetching-catalog-contents.md

@@ -57,3 +57,114 @@ An example `curl` request that assumes the port-forwarding is mapped to port 808
 ```sh
 curl http://localhost:8080/catalogs/operatorhubio/all.json
 ```
+
+# Fetching `Catalog` contents from the `Catalogd` Service outside of the cluster
+
+This section outlines a way of exposing the `Catalogd` Service's endpoints outside the cluster and then accessing the catalog contents using `Ingress`. 
+
+**Prerequisites**
+- [Install kind](https://kind.sigs.k8s.io/docs/user/quick-start/#installation)
+- Install latest version of `Catalogd` by navigating to the [releases page](https://github.com/operator-framework/catalogd/releases) and following the install instructions included in the release you want to install.
+
+1. Create a `kind` cluster with `extraPortMappings` and `node-labels` by running the below command:
+
+    ```sh
+      cat <<EOF | kind create cluster --config=-
+      kind: Cluster
+      apiVersion: kind.x-k8s.io/v1alpha4
+      nodes:
+      - role: control-plane
+        kubeadmConfigPatches:
+        - |
+          kind: InitConfiguration
+          nodeRegistration:
+            kubeletExtraArgs:
+              node-labels: "ingress-ready=true"
+      extraPortMappings:
+      - containerPort: 80
+        hostPort: 80
+        protocol: TCP
+      - containerPort: 443
+        hostPort: 443
+        protocol: TCP
+      EOF
+    ```
+
+    - `extraPortMappings` allows the localhost to make requests to the Ingress controller over ports `80/443`. Setting this config option when creating a cluster allows to forward ports from the host to an ingress controller running on a node.
+    - `node-labels` only allows the ingress controller to run on a specific node(s) matching the label selector.
+
+1. Create a `Catalog` object that points to the OperatorHub Community catalog by running the following command:
+
+    ```sh
+      $ kubectl apply -f - << EOF
+      apiVersion: catalogd.operatorframework.io/v1alpha1
+      kind: Catalog
+        metadata:
+          name: operatorhubio
+        spec:
+          source:
+            type: image
+            image:
+              ref: quay.io/operatorhubio/catalog:latest
+        EOF
+    ```
+
+1. Before proceeding further let's verify that the `Catalog` object was created successfully by running the below command: 
+
+    ```sh
+      $ kubectl describe catalog/operatorhubio
+    ```
+
+1. Now we can proceed to install the `Ingress` controller. We will be using `Ingress NGINX` for the controller. Run the following command to install the `Ingress` controller:
+
+    ```sh
+      $ kubectl apply -f https://raw.githubusercontent.com/kubernetes/ingress-nginx/main/deploy/static/provider/kind/deploy.yaml
+    ```
+
+1. Wait until `Ingress` is ready by running the below `kubectl wait` command: 
+
+    ```sh
+      $ kubectl wait --namespace ingress-nginx \
+      --for=condition=ready pod \
+      --selector=app.kubernetes.io/component=controller \
+      --timeout=90s
+    ```
+
+1. At this point the `Ingress` controller is ready to process requests. Let's create an `Ingress` object by running the below command:
+
+    ```sh
+      $ kubectl apply -f https://github.com/operator-framework/catalogd/tree/main/manifests/overlays/nginx-ingress/resources/nginx_ingress.yaml
+
+        Sample `Ingress` Resource:
+        ```yaml
+        apiVersion: networking.k8s.io/v1
+        kind: Ingress
+        metadata:
+          name: catalogd-nginx-ingress
+          namespace: catalogd-system
+          annotations:
+            nginx.org/proxy-connect-timeout: "30s"
+            nginx.org/proxy-read-timeout: "20s"
+            nginx.org/client-max-body-size: "4m"
+        spec:
+          ingressClassName: nginx
+          rules:
+          - http:
+              paths:
+              - path: /
+                pathType: Prefix
+                backend:
+                  service:
+                    name: catalogd-catalogserver
+                    port:
+                      number: 80
+    ```
+
+
+1. Once the `Ingress` object has been successfully created, issue a `curl` request. Below is an example `curl` request to retrieve all of the catalog contents:
+
+    ```sh
+      $ curl http://localhost/catalogs/operatorhubio/all.json
+    ```
+
+    You can further use the `curl` commands outlined in the [Catalogd README](https://github.com/operator-framework/catalogd/blob/main/README.md) to filter out the JSON content by list of bundles, channels & packages.

manifests/overlays/nginx-ingress/kustomization.yaml

@@ -0,0 +1,4 @@
+resources:
+- ../default
+- resources/nginx_ingress.yaml 
+

manifests/overlays/nginx-ingress/resources/nginx_ingress.yaml

@@ -0,0 +1,22 @@
+apiVersion: networking.k8s.io/v1
+kind: Ingress
+metadata:
+  name: catalogd-nginx-ingress
+  namespace: catalogd-system
+  annotations:
+    nginx.org/proxy-connect-timeout: "30s"
+    nginx.org/proxy-read-timeout: "20s"
+    nginx.org/client-max-body-size: "4m"
+spec:
+  ingressClassName: nginx
+  rules:
+  - http:
+      paths:
+      - path: /
+        pathType: Prefix
+        backend:
+          service:
+            name: catalogd-catalogserver
+            port:
+              number: 80
+