Fix Prometheus operator installation (#3049)

* Fix Prometheus operator installation order

Signed-off-by: Paolo Patierno <ppatierno@live.com>

* Updated doc to use Prometheus Operator bundle for its installation

Signed-off-by: Paolo Patierno <ppatierno@live.com>

* Fixed comment

Signed-off-by: Paolo Patierno <ppatierno@live.com>

documentation/modules/metrics/proc_metrics-deploying-prometheus-operator.adoc

@@ -6,46 +6,27 @@
 
 = Deploying the Prometheus Operator
 
-To deploy the Prometheus Operator to your Kafka cluster, apply the YAML resource files from the https://github.com/coreos/prometheus-operator/tree/master/example/rbac/prometheus-operator[Prometheus CoreOS repository].
+To deploy the Prometheus Operator to your Kafka cluster, apply the YAML bundle resources file from the https://github.com/coreos/prometheus-operator[Prometheus CoreOS repository].
 
 .Procedure
 
-. Download the resource files from the repository and replace the example `namespace` with your own:
+. Download the resource file from the repository and replace the example `namespace` with your own:
 +
 On Linux, use:
 +
 [source,shell,subs=+quotes]
-curl -s https://raw.githubusercontent.com/coreos/prometheus-operator/master/example/rbac/prometheus-operator/prometheus-operator-deployment.yaml | sed -e 's/namespace: .\*/namespace: _my-namespace_/' > prometheus-operator-deployment.yaml
-+
-[source,shell,subs=+quotes]
-curl -s https://raw.githubusercontent.com/coreos/prometheus-operator/master/example/rbac/prometheus-operator/prometheus-operator-cluster-role.yaml > prometheus-operator-cluster-role.yaml
-+
-[source,shell,subs=+quotes]
-curl -s https://raw.githubusercontent.com/coreos/prometheus-operator/master/example/rbac/prometheus-operator/prometheus-operator-cluster-role-binding.yaml | sed -e 's/namespace: .*/namespace: _my-namespace_/' > prometheus-operator-cluster-role-binding.yaml
-+
-[source,shell,subs=+quotes]
-curl -s https://raw.githubusercontent.com/coreos/prometheus-operator/master/example/rbac/prometheus-operator/prometheus-operator-service-account.yaml | sed -e 's/namespace: .*/namespace: _my-namespace_/' > prometheus-operator-service-account.yaml
+curl -s https://raw.githubusercontent.com/coreos/prometheus-operator/master/bundle.yaml | sed -e 's/namespace: .*/namespace: _my-namespace_/' > prometheus-operator-deployment.yaml
 +
 On MacOS, use:
 +
 [source,shell,subs=+quotes]
-curl -s https://raw.githubusercontent.com/coreos/prometheus-operator/master/example/rbac/prometheus-operator/prometheus-operator-deployment.yaml | sed -e '' 's/namespace: .\*/namespace: _my-namespace_/' > prometheus-operator-deployment.yaml
-+
-[source,shell,subs=+quotes]
-curl -s https://raw.githubusercontent.com/coreos/prometheus-operator/master/example/rbac/prometheus-operator/prometheus-operator-cluster-role.yaml > prometheus-operator-cluster-role.yaml
-+
-[source,shell,subs=+quotes]
-curl -s https://raw.githubusercontent.com/coreos/prometheus-operator/master/example/rbac/prometheus-operator/prometheus-operator-cluster-role-binding.yaml | sed -e '' 's/namespace: .*/namespace: _my-namespace_/' > prometheus-operator-cluster-role-binding.yaml
-+
-[source,shell,subs=+quotes]
-curl -s https://raw.githubusercontent.com/coreos/prometheus-operator/master/example/rbac/prometheus-operator/prometheus-operator-service-account.yaml | sed -e '' 's/namespace: .*/namespace: _my-namespace_/' > prometheus-operator-service-account.yaml
+curl -s https://raw.githubusercontent.com/coreos/prometheus-operator/master/bundle.yaml | sed -e '' 's/namespace: .*/namespace: _my-namespace_/' > prometheus-operator-deployment.yaml
 +
 NOTE: If it is not required, you can manually remove the `spec.template.spec.securityContext` property from the `prometheus-operator-deployment.yaml` file.
 
 . Deploy the Prometheus Operator:
 +
 [source,shell,subs="+attributes"]
 kubectl apply -f prometheus-operator-deployment.yaml
-kubectl apply -f prometheus-operator-cluster-role.yaml
-kubectl apply -f prometheus-operator-cluster-role-binding.yaml
-kubectl apply -f prometheus-operator-service-account.yaml
++
+NOTE: The Prometheus Operator installation works with Kubernetes 1.18+. To check which version to use with a different Kubernetes version, refer to the https://github.com/coreos/kube-prometheus#kubernetes-compatibility-matrix[Kubernetes compatibility matrix].