add custom vts metrics example

examples/customization/custom-vts-metrics/nginx/README.md

@@ -0,0 +1,74 @@
+# Deploying the Nginx Ingress controller
+
+This example aims to demonstrate the deployment of an nginx ingress controller and
+use a ConfigMap to enable nginx vts module and export metrics for prometheus.
+
+## Default Backend
+
+The default backend is a Service capable of handling all url paths and hosts the
+nginx controller doesn't understand. This most basic implementation just returns
+a 404 page:
+
+```console
+$ kubectl apply -f default-backend.yaml
+deployment "default-http-backend" created
+service "default-http-backend" created
+
+$ kubectl -n kube-system get po
+NAME                                    READY     STATUS    RESTARTS   AGE
+default-http-backend-2657704409-qgwdd   1/1       Running   0          28s
+```
+
+## Custom configuration
+
+```console
+$ cat nginx-vts-metrics-conf.yaml
+apiVersion: v1
+data:
+  enable-vts-status: "true"
+kind: ConfigMap
+metadata:
+  name: nginx-vts-metrics-conf
+  namespace: kube-system
+```
+
+```console
+$ kubectl create -f nginx-vts-metrics-conf.yaml
+```
+
+## Custom DH parameters secret
+
+```console
+$> openssl dhparam 1024 2> /dev/null | base64
+LS0tLS1CRUdJTiBESCBQQVJBTUVURVJ...
+```
+
+```console
+$ cat ssl-dh-param.yaml
+apiVersion: v1
+data:
+  dhparam.pem: "LS0tLS1CRUdJTiBESCBQQVJBTUVURVJ..."
+kind: Secret
+type: Opaque
+metadata:
+  name: lb-dhparam
+  namespace: kube-system
+```
+## Controller
+
+You can deploy the controller as follows:
+
+```console
+$ kubectl apply -f nginx-ingress-controller.yaml
+deployment "nginx-ingress-controller" created
+
+$ kubectl -n kube-system get po
+NAME                                       READY     STATUS    RESTARTS   AGE
+default-http-backend-2657704409-qgwdd      1/1       Running   0          2m
+nginx-ingress-controller-873061567-4n3k2   1/1       Running   0          42s
+```
+
+## Test
+
+Check the contents of the configmap is present in the nginx.conf file using:
+`kubectl exec nginx-ingress-controller-873061567-4n3k2 -n kube-system cat /etc/nginx/nginx.conf`