Edits of Cluster Monitoring Operator docs

modules/configuring-cluster-monitoring.adoc

@@ -0,0 +1,82 @@
+// Module included in the following assemblies:
+//
+// * scalability_and_performance/scaling-cluster-monitoring-operator.adoc
+
+[id="configuring-cluster-monitoring-{context}"]
+= Configuring cluster monitoring
+
+.Procedure
+
+To increase the storage capacity for Prometheus:
+
+. Create a YAML configuration file, `cluster-monitoring-config.yml. For example:
++
+----
+apiVersion: v1
+kind: ConfigMap
+data:
+  config.yaml: |
+    prometheusOperator:
+      baseImage: quay.io/coreos/prometheus-operator
+      prometheusConfigReloaderBaseImage: quay.io/coreos/prometheus-config-reloader
+      configReloaderBaseImage: quay.io/coreos/configmap-reload
+      nodeSelector:
+        node-role.kubernetes.io/infra: ""
+    prometheusK8s:
+      retention: {{PROMETHEUS_RETENTION_PERIOD}} <1>
+      baseImage: openshift/prometheus
+      nodeSelector:
+        node-role.kubernetes.io/infra: ""
+      volumeClaimTemplate:
+        spec:
+          storageClassName: gp2
+          resources:
+            requests:
+              storage: {{PROMETHEUS_STORAGE_SIZE}} <2>
+    alertmanagerMain:
+      baseImage: openshift/prometheus-alertmanager
+      nodeSelector:
+        node-role.kubernetes.io/infra: ""
+      volumeClaimTemplate:
+        spec:
+          storageClassName: gp2
+          resources:
+            requests:
+              storage: {{ALERTMANAGER_STORAGE_SIZE}} <3>
+    nodeExporter:
+      baseImage: openshift/prometheus-node-exporter
+    kubeRbacProxy:
+      baseImage: quay.io/coreos/kube-rbac-proxy
+    kubeStateMetrics:
+      baseImage: quay.io/coreos/kube-state-metrics
+      nodeSelector:
+        node-role.kubernetes.io/infra: ""
+    grafana:
+      baseImage: grafana/grafana
+      nodeSelector:
+        node-role.kubernetes.io/infra: ""
+    auth:
+      baseImage: openshift/oauth-proxy
+    k8sPrometheusAdapter:
+      nodeSelector:
+        node-role.kubernetes.io/infra: ""
+metadata:
+  name: cluster-monitoring-config
+namespace: openshift-monitoring
+----
+<1> A typical value is `PROMETHEUS_RETENTION_PERIOD=15d`. Units are measured in
+time using one of these suffixes: s, m, h, d.
+<2> A typical value is `PROMETHEUS_STORAGE_SIZE=2000Gi`. Storage values can be a
+plain integer or as a fixed-point integer using one of these suffixes: E, P, T,
+G, M, K. You can also use the power-of-two equivalents: Ei, Pi, Ti, Gi, Mi, Ki.
+<3> A typical value is `ALERTMANAGER_STORAGE_SIZE=20Gi`. Storage values can be a
+plain integer or as a fixed-point integer using one of these suffixes: E, P, T,
+G, M, K. You can also use the power-of-two equivalents: Ei, Pi, Ti, Gi, Mi, Ki.
+
+. Set the values like the retention period and storage sizes.
+
+. Apply the changes by running:
++
+----
+$ oc create -f cluster-monitoring-config.yml
+----

modules/prometheus-database-storage-requirements.adoc

@@ -45,10 +45,8 @@ Red Hat performed various tests for different scale sizes.
 Approximately 20 percent of the expected size was added as overhead to ensure
 that the storage requirements do not exceed the calculated value.
 
-The above calculation is for the default {product-title}
-*cluster-monitoring-operator*. For higher scale, edit the
-`openshift_cluster_monitoring_operator_prometheus_storage_capacity` variable in
-the Ansible inventory file, which defaults to `50Gi`.
+The above calculation is for the default {product-title} Cluster Monitoring
+Operator.
 
 [NOTE]
 ====
@@ -76,5 +74,15 @@ Currently, OpenStack environments are not supported for {product-title} 4.0.
 
 [IMPORTANT]
 ====
-Currently, CNS is not supported in {product-title} 4.0.
+OpenShift Container Storage (OCS) is currently a Technology Preview feature.
+ifdef::openshift-enterprise[]
+Technology Preview features are not supported with Red Hat production service
+level agreements (SLAs), might not be functionally complete, and Red Hat does
+not recommend to use them for production. These features provide early access to
+upcoming product features, enabling customers to test functionality and provide
+feedback during the development process.
+
+See the link:https://access.redhat.com/support/offerings/techpreview/[Red Hat
+Technology Preview features support scope] for more information.
+endif::[]
 ====

scalability_and_performance/scaling-cluster-monitoring-operator.adoc

@@ -5,11 +5,13 @@ include::modules/common-attributes.adoc[]
 
 toc::[]
 
-{product-title} exposes metrics that the *cluster-monitoring-operator* collects
-and stores in back-ends. As an {product-title} administrator, you can view
-system resources, containers and components metrics in one dashboard interface,
-Grafana.
+{product-title} exposes metrics that the Cluster Monitoring Operator collects
+and stores in the Prometheus-based monitoring stack. As an {product-title}
+administrator, you can view system resources, containers and components metrics
+in one dashboard interface, Grafana.
 
 include::modules/prometheus-database-storage-requirements.adoc[leveloffset=+1]
 
+include::modules/configuring-cluster-monitoring.adoc[leveloffset=+1]
+
 include::modules/scaling-prometheus-components.adoc[leveloffset=+1]