Before you begin, you must:

Replace a worker node

In certain situations, you may want to delete a worker node and have Cluster API replace it with a newly-provisioned machine.

  1. Identify the name of the node to delete.

    List the nodes:

    kubectl --kubeconfig ${CLUSTER_NAME}.conf get nodes

    The output from this command resembles the following:

    NAME                                       STATUS   ROLES                  AGE   VERSION
    d2iq-e2e-cluster-1-control-plane-7llgd     Ready    control-plane,master   20h   v1.22.8
    d2iq-e2e-cluster-1-control-plane-vncbl     Ready    control-plane,master   20h   v1.22.8
    d2iq-e2e-cluster-1-control-plane-wbgrm     Ready    control-plane,master   19h   v1.22.8
    d2iq-e2e-cluster-1-md-0-74c849dc8c-67rv4   Ready    <none>                 20h   v1.22.8
    d2iq-e2e-cluster-1-md-0-74c849dc8c-n2skc   Ready    <none>                 20h   v1.22.8
    d2iq-e2e-cluster-1-md-0-74c849dc8c-nkftv   Ready    <none>                 20h   v1.22.8
    d2iq-e2e-cluster-1-md-0-74c849dc8c-sqklv   Ready    <none>                 20h   v1.22.8

  2. Export a variable with the node name to use in the next steps:

    This example uses the name d2iq-e2e-cluster-1-md-0-74c849dc8c-67rv4.

    export NAME_NODE_TO_DELETE="d2iq-e2e-cluster-1-md-0-74c849dc8c-67rv4"

  3. Delete the Machine resource with the command:

    NAME_MACHINE_TO_DELETE=$(kubectl --kubeconfig ${CLUSTER_NAME}.conf get machine -ojsonpath="{.items[?(\"$NAME_NODE_TO_DELETE\")]}")
    kubectl --kubeconfig ${CLUSTER_NAME}.conf delete machine "$NAME_MACHINE_TO_DELETE"
    CODE "d2iq-e2e-cluster-1-md-0-74c849dc8c-67rv4" deleted

    The command does not return immediately, but it does return after the Machine resource is deleted.

    A few minutes after the Machine resource is deleted, the corresponding Node resource is also deleted.

  4. Observe the Machine resource replacement using this command:

    kubectl --kubeconfig ${CLUSTER_NAME}.conf get machinedeployment

    NAME                      CLUSTER              REPLICAS   READY   UPDATED   UNAVAILABLE   PHASE       AGE   VERSION
    d2iq-e2e-cluster-1-md-0   d2iq-e2e-cluster-1   4          3       4         1             ScalingUp   20h   v1.22.8

    In this example, there exist 4 replicas, but only 3 are ready. One replica is unavailable, and the ScalingUp phase means a new Machine is being created.

  5. Identify the replacement Machine using this command:

    export NAME_NEW_MACHINE=$(kubectl --kubeconfig ${CLUSTER_NAME}.conf get machines \${CLUSTER_NAME}-md-0 \
    echo "$NAME_NEW_MACHINE"

    If the output is empty, the new Machine has probably exited the Provisioning phase and entered the Running phase.

  6. Identify the replacement Node using this command:

    kubectl --kubeconfig ${CLUSTER_NAME}.conf get nodes \

    The output should be similar to this example:


    If the output is empty, the Node resource is not yet available, or does not yet have the expected annotation. Wait a few minutes, then repeat the command.