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You use node selectors to deploy the Elasticsearch, Kibana, and Curator pods to different nodes.

Moving the cluster logging resources

You can configure the Cluster Logging Operator to deploy the pods for any or all of the Cluster Logging components, Elasticsearch, Kibana, and Curator to different nodes. You cannot move the Cluster Logging Operator pod from its installed location.

For example, you can move the Elasticsearch pods to a separate node because of high CPU, memory, and disk requirements.

You should set your MachineSet to use at least 6 replicas.

Prerequisites
  • Cluster logging and Elasticsearch must be installed. These features are not installed by default.

Procedure
  1. Edit the Cluster Logging Custom Resource in the openshift-logging project:

    $ oc edit ClusterLogging instance
    apiVersion: logging.openshift.io/v1
    kind: ClusterLogging
    
    ....
    
    spec:
      collection:
        logs:
          fluentd:
            resources: null
          type: fluentd
      curation:
        curator:
          nodeSelector: (1)
              node-role.kubernetes.io/infra: ''
          resources: null
          schedule: 30 3 * * *
        type: curator
      logStore:
        elasticsearch:
          nodeCount: 3
          nodeSelector: (1)
              node-role.kubernetes.io/infra: ''
          redundancyPolicy: SingleRedundancy
          resources:
            limits:
              cpu: 500m
              memory: 16Gi
            requests:
              cpu: 500m
              memory: 16Gi
          storage: {}
        type: elasticsearch
      managementState: Managed
      visualization:
        kibana:
          nodeSelector: (1)
              node-role.kubernetes.io/infra: '' (1)
          proxy:
            resources: null
          replicas: 1
          resources: null
        type: kibana
    
    ....
1 Add a nodeSelector parameter with the appropriate value to the component you want to move. You can use a nodeSelector in the format shown or use <key>: <value> pairs, based on the value specified for the node.
Verification steps

To verify that a component has moved, you can use the oc get pod -o wide command.

For example:

  • You want to move the Kibana pod from the ip-10-0-147-79.us-east-2.compute.internal node:

    $ oc get pod kibana-5b8bdf44f9-ccpq9 -o wide
    NAME                      READY   STATUS    RESTARTS   AGE   IP            NODE                                        NOMINATED NODE   READINESS GATES
    kibana-5b8bdf44f9-ccpq9   2/2     Running   0          27s   10.129.2.18   ip-10-0-147-79.us-east-2.compute.internal   <none>           <none>
  • You want to move the Kibana Pod to the ip-10-0-139-48.us-east-2.compute.internal node, a dedicated infrastructure node:

    $ oc get nodes
    NAME                                         STATUS   ROLES          AGE   VERSION
    ip-10-0-133-216.us-east-2.compute.internal   Ready    master         60m   v1.16.2
    ip-10-0-139-146.us-east-2.compute.internal   Ready    master         60m   v1.16.2
    ip-10-0-139-192.us-east-2.compute.internal   Ready    worker         51m   v1.16.2
    ip-10-0-139-241.us-east-2.compute.internal   Ready    worker         51m   v1.16.2
    ip-10-0-147-79.us-east-2.compute.internal    Ready    worker         51m   v1.16.2
    ip-10-0-152-241.us-east-2.compute.internal   Ready    master         60m   v1.16.2
    ip-10-0-139-48.us-east-2.compute.internal    Ready    infra          51m   v1.16.2

    Note that the node has a node-role.kubernetes.io/infra: '' label:

    $ oc get node ip-10-0-139-48.us-east-2.compute.internal -o yaml
    
    kind: Node
    apiVersion: v1
    metadata:
      name: ip-10-0-139-48.us-east-2.compute.internal
      selfLink: /api/v1/nodes/ip-10-0-139-48.us-east-2.compute.internal
      uid: 62038aa9-661f-41d7-ba93-b5f1b6ef8751
      resourceVersion: '39083'
      creationTimestamp: '2020-04-13T19:07:55Z'
      labels:
        node-role.kubernetes.io/infra: ''
    ....
  • To move the Kibana Pod, edit the Cluster Logging CR to add a node selector:

    apiVersion: logging.openshift.io/v1
    kind: ClusterLogging
    
    ....
    
    spec:
    
    ....
    
      visualization:
        kibana:
          nodeSelector: (1)
            node-role.kubernetes.io/infra: '' (1)
          proxy:
            resources: null
          replicas: 1
          resources: null
        type: kibana
    1 Add a node selector to match the label in the node specification.
  • After you save the CR, the current Kibana pod is terminated and new pod is deployed:

    $ oc get pods
    NAME                                            READY   STATUS        RESTARTS   AGE
    cluster-logging-operator-84d98649c4-zb9g7       1/1     Running       0          29m
    elasticsearch-cdm-hwv01pf7-1-56588f554f-kpmlg   2/2     Running       0          28m
    elasticsearch-cdm-hwv01pf7-2-84c877d75d-75wqj   2/2     Running       0          28m
    elasticsearch-cdm-hwv01pf7-3-f5d95b87b-4nx78    2/2     Running       0          28m
    fluentd-42dzz                                   1/1     Running       0          28m
    fluentd-d74rq                                   1/1     Running       0          28m
    fluentd-m5vr9                                   1/1     Running       0          28m
    fluentd-nkxl7                                   1/1     Running       0          28m
    fluentd-pdvqb                                   1/1     Running       0          28m
    fluentd-tflh6                                   1/1     Running       0          28m
    kibana-5b8bdf44f9-ccpq9                         2/2     Terminating   0          4m11s
    kibana-7d85dcffc8-bfpfp                         2/2     Running       0          33s
  • The new pod is on the ip-10-0-139-48.us-east-2.compute.internal node:

    $ oc get pod kibana-7d85dcffc8-bfpfp -o wide
    NAME                      READY   STATUS        RESTARTS   AGE   IP            NODE                                        NOMINATED NODE   READINESS GATES
    kibana-7d85dcffc8-bfpfp   2/2     Running       0          43s   10.131.0.22   ip-10-0-139-48.us-east-2.compute.internal   <none>           <none>
  • After a few moments, the original Kibana pod is removed.

    $ oc get pods
    NAME                                            READY   STATUS    RESTARTS   AGE
    cluster-logging-operator-84d98649c4-zb9g7       1/1     Running   0          30m
    elasticsearch-cdm-hwv01pf7-1-56588f554f-kpmlg   2/2     Running   0          29m
    elasticsearch-cdm-hwv01pf7-2-84c877d75d-75wqj   2/2     Running   0          29m
    elasticsearch-cdm-hwv01pf7-3-f5d95b87b-4nx78    2/2     Running   0          29m
    fluentd-42dzz                                   1/1     Running   0          29m
    fluentd-d74rq                                   1/1     Running   0          29m
    fluentd-m5vr9                                   1/1     Running   0          29m
    fluentd-nkxl7                                   1/1     Running   0          29m
    fluentd-pdvqb                                   1/1     Running   0          29m
    fluentd-tflh6                                   1/1     Running   0          29m
    kibana-7d85dcffc8-bfpfp                         2/2     Running   0          62s