Chapter 7. Gluster Block Storage as Backend for Logging and Metrics
Following section guides to configure Gluster Block Storage as the backend storage for logging and metrics
Block volume expansion is now supported in OpenShift Container Storage 3.11. Refer to Section 3.2.3, “Block volume expansion”.
7.1. Prerequisites
Before setting gluster block storage as the backend for logging or metrics, check if the following prerequisites are met:
In the storageclass file, check if the default storage class is set to the storage class of gluster block. For example:
# oc get storageclass NAME TYPE gluster-block gluster.org/glusterblock
If the default is not set to
gluster-block(or any other name that you have provided) then execute the following command. For example:# oc patch storageclass gluster-block -p '{"metadata": {"annotations":{"storageclass.kubernetes.io/is-default-class":"true"}}}'Execute the following command to verify:
oc get storageclass NAME TYPE gluster-block (default) gluster.org/glusterblock
7.2. Enabling Gluster Block Storage as Backend for Logging
Follow the tasks mentioned below to enable Gluster Block Storage as backend for logging:
- To enable logging in Openshift Container platform, see https://access.redhat.com/documentation/en-us/openshift_container_platform/3.11/html-single/configuring_clusters/#install-config-aggregate-logging
The
openshift_logging_es_pvc_dynamicansible variable has to be set to true.[OSEv3:vars] openshift_logging_es_pvc_dynamic=true
For example, a sample set of variables for openshift_logging_ are listed below.
openshift_logging_install_logging=true openshift_logging_es_pvc_dynamic=true openshift_logging_kibana_nodeselector={"node-role.kubernetes.io/infra": "true"} openshift_logging_curator_nodeselector={"node-role.kubernetes.io/infra": "true"} openshift_logging_es_nodeselector={"node-role.kubernetes.io/infra": "true"} openshift_logging_es_pvc_size=10Gi openshift_logging_es_pvc_storage_class_name="glusterfs-registry-block"- Run the Ansible playbook. For more information, see .https://access.redhat.com/documentation/en-us/openshift_container_platform/3.11/html-single/configuring_clusters/#install-config-aggregate-logging
To verify, execute the following command:
# oc get pods -n openshift-logging
For more information regarding logging storage considerations, see https://access.redhat.com/documentation/en-us/openshift_container_platform/3.11/html-single/configuring_clusters/#install-config-aggregate-logging-sizing-guidelines-storage.
7.3. Enabling Gluster Block Storage as Backend for Metrics
Follow the tasks mentioned below to enable Gluster Block Storage as backend for metrics
By default, since Container Native Storage performs three-way replication, data will be available to the restarted node from anywhere in the cluster. As a result, it is recommended that Cassandra-level replication is turned off to avoid capacity overhead
- To enable metrics in Openshift Container platform, see https://access.redhat.com/documentation/en-us/openshift_container_platform/3.11/html-single/configuring_clusters/#install-config-cluster-metrics
The
openshift_metrics_cassandra_storage_typeansible variable should be set todynamic:[OSEv3:vars]openshift_metrics_cassandra_storage_type=dynamic
For example, a sample set of variables for openshift_metrics_ are listed below.
openshift_metrics_install_metrics=true openshift_metrics_storage_kind=dynamic openshift_metrics_hawkular_nodeselector={"node-role.kubernetes.io/infra": "true"} openshift_metrics_cassandra_nodeselector={"node-role.kubernetes.io/infra": "true"} openshift_metrics_heapster_nodeselector={"node-role.kubernetes.io/infra": "true"} openshift_metrics_storage_volume_size=10Gi openshift_metrics_cassandra_pvc_storage_class_name="glusterfs-registry-block"- Run the Ansible playbook. For more information, see https://access.redhat.com/documentation/en-us/openshift_container_platform/3.11/html-single/configuring_clusters/#install-config-cluster-metrics.
To verify, execute the following command:
# oc get pods --namespace openshift-infra
It should list the following pods running:
heapster-cassandra heapster-metrics hawkular-&*9
For more information regarding metrics storage considerations, see https://access.redhat.com/documentation/en-us/openshift_container_platform/3.11/html-single/configuring_clusters/#metrics-data-storage.
7.4. Verifying if Gluster Block is Setup as Backend
Execute the following commands to verify if gluster block is setup as the backend for logging and metrics:
To get an overview of the infrastructure, execute the following command:
# oc get pods -n logging -o jsonpath='{range .items[].status.containerStatuses[]}{"Name: "}{.name}{"\n "}{"Image: "}{.image}{"\n"}{" State: "}{.state}{"\n"}{end}'To get the details of all the persistent volume claims, execute the following command:
# oc get pvc
To get the details of the pvc, execute the following command:
# oc describe pvc <claim_name>
Verify the volume is mountable and that permissions allow read/write. Also, PVC claim name should match the dynamically provisioned gluster block storage class.
For more information, see https://access.redhat.com/documentation/en-us/openshift_container_platform/3.11/html-single/configuring_clusters/#install-config-aggregate-logging-sizing.
