144 Red Hat OpenShift and IBM Cloud Paks on IBM Power Systems: Volume 1
The Monitoring stack is installed with OpenShift Container Platform by default. You can 
prevent it from being installed by setting 
openshift_cluster_monitoring_operator_install=False in the Ansible inventory file.
By default, persistent storage is disabled for Prometheus time-series data and for 
Alertmanager notifications and silences. You can configure the cluster to persistently store 
any one of them or both.
To enable persistent storage of Prometheus time-series data, set 
openshift_cluster_monitoring_operator_prometheus_storage_enabled=True in the Ansible 
inventory file.
To enable persistent storage of Alertmanager notifications and silences, set 
openshift_cluster_monitoring_operator_alertmanager_storage_enabled=True in the 
Ansible inventory file.
To specify the size of the persistent volume claim for Prometheus and Alertmanager, change 
the following Ansible variables:
/SM590000openshift_cluster_monitoring_operator_prometheus_storage_capacity (default: 
50Gi)
/SM590000openshift_cluster_monitoring_operator_alertmanager_storage_capacity (default: 
2Gi)
Each of these variables applies only if its corresponding storage_enabled variable is set to 
True.
After you enable dynamic storage, you can also set the storageclass for the persistent 
volume claim for each component in the Ansible inventory file:
/SM590000openshift_cluster_monitoring_operator_prometheus_storage_class_name (default: 
"")
/SM590000openshift_cluster_monitoring_operator_alertmanager_storage_class_name (default: 
"")
Each of these variables applies only if its corresponding storage_enabled variable is set to 
True.
Example 6-11 shows a sample Cluster Monitoring in the Ansible inventory file.
Example 6-11   Cluster Monitoring in the Ansible inventory file
##-----------------------------------------------------------------------##
## Prometheus Cluster Monitoring
##-----------------------------------------------------------------------##
https://docs.openshift.com/container-platform/3.11/install_config/prometheus_cluster_monito
ring.html
openshift_cluster_monitoring_operator_install=False
openshift_prometheus_node_selector={"node-role.kubernetes.io/infra":"true"}
# Enable persistent storage of Prometheus time-series data (default False)
openshift_cluster_monitoring_operator_prometheus_storage_enabled=False
# Enable persistent storage of Alertmanager notifications (default False)
openshift_cluster_monitoring_operator_alertmanager_storage_enabled=False
# Dynamic storage allocation for Prometheus services
openshift_cluster_monitoring_operator_prometheus_storage_capacity=32Gi
openshift_cluster_monitoring_operator_alertmanager_storage_capacity=4Gi
# Storage class to use if persistent storage enabled
# NOTE: it will use storageclass default if storage class not specified
openshift_cluster_monitoring_operator_prometheus_storage_class_name='ibm-powervc-k8s-volume
-default'