# Cluster monitoring
You can configure persistent storage for the cluster monitoring components using the Ansible playbook
playbooks/monitoring.yml. This playbook automates the configuration of persistent storage for the Prometheus
and Alertmanager pods.
A separate storage volume is created for each Prometheus and Alertmanager pod. On the OpenShift Container Platform,
this is achieved using persistent volume claims (PVC) and persistent volumes (PV). You can customize both the storage
class and the size of the persistent volumes used to store Prometheus and Alertmanager data by editing the
following variables in the file playbooks/roles/monitoring/vars/main.yml:
| Variable | Description |
|---|---|
| prometheus_pv_size | Size of the persistent volume used to hold Prometheus data (default size is '40Gi') |
| prometheus_pv_storage_class | The storage class to use when creating Prometheus persistent volumes (default storage class name is 'thin') |
| alertmanager_pv_size | Size of the persistent volume used to hold Alertmanager data (default size is '40Gi') |
| alertmanager_pv_storage_class | The storage class to use when creating Alertmanager persistent volumes (default storage class name is 'thin') |
After making the appropriate customizations to the above variables, re-deploy the cluster monitoring components by changing into the directory where you cloned the OpenShift-on-SimpliVity repository and running the appropriate playbook:
$ cd ~/OpenShift-on-SimpliVity
$ ansible-playbook -i hosts playbooks/monitoring.yml
The playbook takes approximately 1-2 minutes to complete. However, it may take some additional time for the various cluster monitoring components to successfully re-launch with their newly created persistent storage volumes:
$ oc get pvc -n openshift-monitoring
NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE
alertmanager-claim-alertmanager-main-0 Bound pvc-3ec286d3-0d3b-11ea-9074-00505681c3ee 40Gi RWO thin 2m23s
alertmanager-claim-alertmanager-main-1 Bound pvc-3ec845dd-0d3b-11ea-9074-00505681c3ee 40Gi RWO thin 2m23s
alertmanager-claim-alertmanager-main-2 Bound pvc-3ed13223-0d3b-11ea-9074-00505681c3ee 40Gi RWO thin 2m23s
prometheus-claim-prometheus-k8s-0 Bound pvc-3ee82db4-0d3b-11ea-9074-00505681c3ee 40Gi RWO thin 2m23s
prometheus-claim-prometheus-k8s-1 Bound pvc-3ef1c00a-0d3b-11ea-9074-00505681c3ee 40Gi RWO thin 2m23s