monitoring-moving-monitoring-components-to-different-nodes.adoc

Moving monitoring components to different nodes

You can move any of the monitoring stack components to specific nodes.

Prerequisites

• Make sure you have the cluster-monitoring-config ConfigMap object with the data/config.yaml section.

Procedure

1. Start editing the cluster-monitoring-config ConfigMap:

   $ oc -n openshift-monitoring edit configmap cluster-monitoring-config

2. Specify the nodeSelector constraint for the component under data/config.yaml:

   apiVersion: v1
   kind: ConfigMap
   metadata:
     name: cluster-monitoring-config
     namespace: openshift-monitoring
   data:
     config.yaml: |
       <component>:
         nodeSelector:
           <node_key>: <node_value>
           <node_key>: <node_value>
           <...>

   Substitute <component> accordingly and substitute <node_key>: <node_value> with the map of key-value pairs that specifies the destination node. Often, only a single key-value pair is used.

   The component can only run on a node that has each of the specified key-value pairs as labels. The node can have additional labels as well.

   For example, to move components to the node that is labeled foo: bar, use:

   apiVersion: v1
   kind: ConfigMap
   metadata:
     name: cluster-monitoring-config
     namespace: openshift-monitoring
   data:
     config.yaml: |
       prometheusOperator:
         nodeSelector:
           foo: bar
       prometheusK8s:
         nodeSelector:
           foo: bar
       alertmanagerMain:
         nodeSelector:
           foo: bar
       kubeStateMetrics:
         nodeSelector:
           foo: bar
       grafana:
         nodeSelector:
           foo: bar
       telemeterClient:
         nodeSelector:
           foo: bar
       k8sPrometheusAdapter:
         nodeSelector:
           foo: bar

3. Save the file to apply the changes. The components affected by the new configuration are moved to new nodes automatically.

Additional resources

• See the Kubernetes documentation for details on the nodeSelector constraint.