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This document describes the process to replace a single unhealthy etcd member.

This process depends on whether the etcd member is unhealthy because the machine is not running or the node is not ready, or whether it is unhealthy because the etcd pod is crashlooping.

If you have lost the majority of your control plane hosts, leading to etcd quorum loss, then you must follow the disaster recovery procedure to restore to a previous cluster state instead of this procedure.

If the control plane certificates are not valid on the member being replaced, then you must follow the procedure to recover from expired control plane certificates instead of this procedure.

If a control plane node is lost and a new one is created, the etcd cluster Operator handles generating the new TLS certificates and adding the node as an etcd member.

Prerequisites

  • Take an etcd backup prior to replacing an unhealthy etcd member.

Identifying an unhealthy etcd member

You can identify if your cluster has an unhealthy etcd member.

Prerequisites
  • Access to the cluster as a user with the cluster-admin role.

Procedure
  1. Check the status of the EtcdMembersAvailable status condition using the following command:

    $ oc get etcd -o=jsonpath='{range .items[0].status.conditions[?(@.type=="EtcdMembersAvailable")]}{.message}{"\n"}'
  2. Review the output:

    2 of 3 members are available, ip-10-0-131-183.ec2.internal is unhealthy

    This example output shows that the ip-10-0-131-183.ec2.internal etcd member is unhealthy.

Determining the state of the unhealthy etcd member

The steps to replace an unhealthy etcd member depend on which of the following states your etcd member is in:

  • The machine is not running or the node is not ready

  • The etcd pod is crashlooping

This procedure determines which state your etcd member is in. This enables you to know which procedure to follow to replace the unhealthy etcd member.

If you are aware that the machine is not running or the node is not ready, but you expect it to return to a healthy state soon, then you do not need to perform a procedure to replace the etcd member. The etcd cluster Operator will automatically sync when the machine or node returns to a healthy state.

Prerequisites
  • You have access to the cluster as a user with the cluster-admin role.

  • You have identified an unhealthy etcd member.

Procedure
  1. Determine if the machine is not running:

    $ oc get machines -A -ojsonpath='{range .items[*]}{@.status.nodeRef.name}{"\t"}{@.status.providerStatus.instanceState}{"\n"}' | grep -v running
    Example output
    ip-10-0-131-183.ec2.internal  stopped (1)
    
    1 This output lists the node and the status of the node’s machine. If the status is anything other than running, then the machine is not running.

    If the machine is not running, then follow the Replacing an unhealthy etcd member whose machine is not running or whose node is not ready procedure.

  2. Determine if the node is not ready.

    If either of the following scenarios are true, then the node is not ready.

    • If the machine is running, then check whether the node is unreachable:

      $ oc get nodes -o jsonpath='{range .items[*]}{"\n"}{.metadata.name}{"\t"}{range .spec.taints[*]}{.key}{" "}' | grep unreachable
      Example output
      ip-10-0-131-183.ec2.internal	node-role.kubernetes.io/master node.kubernetes.io/unreachable node.kubernetes.io/unreachable (1)
      
      1 If the node is listed with an unreachable taint, then the node is not ready.
    • If the node is still reachable, then check whether the node is listed as NotReady:

      $ oc get nodes -l node-role.kubernetes.io/master | grep "NotReady"
      Example output
      ip-10-0-131-183.ec2.internal   NotReady   master   122m   v1.22.1 (1)
      
      1 If the node is listed as NotReady, then the node is not ready.

    If the node is not ready, then follow the Replacing an unhealthy etcd member whose machine is not running or whose node is not ready procedure.

  3. Determine if the etcd pod is crashlooping.

    If the machine is running and the node is ready, then check whether the etcd pod is crashlooping.

    1. Verify that all control plane nodes are listed as Ready:

      $ oc get nodes -l node-role.kubernetes.io/master
      Example output
      NAME                           STATUS   ROLES    AGE     VERSION
      ip-10-0-131-183.ec2.internal   Ready    master   6h13m   v1.22.1
      ip-10-0-164-97.ec2.internal    Ready    master   6h13m   v1.22.1
      ip-10-0-154-204.ec2.internal   Ready    master   6h13m   v1.22.1
    2. Check whether the status of an etcd pod is either Error or CrashloopBackoff:

      $ oc get pods -n openshift-etcd | grep -v etcd-quorum-guard | grep etcd
      Example output
      etcd-ip-10-0-131-183.ec2.internal                2/3     Error       7          6h9m (1)
      etcd-ip-10-0-164-97.ec2.internal                 3/3     Running     0          6h6m
      etcd-ip-10-0-154-204.ec2.internal                3/3     Running     0          6h6m
      1 Since this status of this pod is Error, then the etcd pod is crashlooping.

    If the etcd pod is crashlooping, then follow the Replacing an unhealthy etcd member whose etcd pod is crashlooping procedure.

Replacing the unhealthy etcd member

Depending on the state of your unhealthy etcd member, use one of the following procedures:

Replacing an unhealthy etcd member whose machine is not running or whose node is not ready

This procedure details the steps to replace an etcd member that is unhealthy either because the machine is not running or because the node is not ready.

Prerequisites
  • You have identified the unhealthy etcd member.

  • You have verified that either the machine is not running or the node is not ready.

  • You have access to the cluster as a user with the cluster-admin role.

  • You have taken an etcd backup.

    It is important to take an etcd backup before performing this procedure so that your cluster can be restored if you encounter any issues.

Procedure
  1. Remove the unhealthy member.

    1. Choose a pod that is not on the affected node:

      In a terminal that has access to the cluster as a cluster-admin user, run the following command:

      $ oc get pods -n openshift-etcd | grep -v etcd-quorum-guard | grep etcd
      Example output
      etcd-ip-10-0-131-183.ec2.internal                3/3     Running     0          123m
      etcd-ip-10-0-164-97.ec2.internal                 3/3     Running     0          123m
      etcd-ip-10-0-154-204.ec2.internal                3/3     Running     0          124m
    2. Connect to the running etcd container, passing in the name of a pod that is not on the affected node:

      In a terminal that has access to the cluster as a cluster-admin user, run the following command:

      $ oc rsh -n openshift-etcd etcd-ip-10-0-154-204.ec2.internal
    3. View the member list:

      sh-4.2# etcdctl member list -w table
      Example output
      +------------------+---------+------------------------------+---------------------------+---------------------------+
      |        ID        | STATUS  |             NAME             |        PEER ADDRS         |       CLIENT ADDRS        |
      +------------------+---------+------------------------------+---------------------------+---------------------------+
      | 6fc1e7c9db35841d | started | ip-10-0-131-183.ec2.internal | https://10.0.131.183:2380 | https://10.0.131.183:2379 |
      | 757b6793e2408b6c | started |  ip-10-0-164-97.ec2.internal |  https://10.0.164.97:2380 |  https://10.0.164.97:2379 |
      | ca8c2990a0aa29d1 | started | ip-10-0-154-204.ec2.internal | https://10.0.154.204:2380 | https://10.0.154.204:2379 |
      +------------------+---------+------------------------------+---------------------------+---------------------------+

      Take note of the ID and the name of the unhealthy etcd member, because these values are needed later in the procedure. The $ etcdctl endpoint health command will list the removed member until the procedure of replacement is finished and a new member is added.

    4. Remove the unhealthy etcd member by providing the ID to the etcdctl member remove command:

      sh-4.2# etcdctl member remove 6fc1e7c9db35841d
      Example output
      Member 6fc1e7c9db35841d removed from cluster ead669ce1fbfb346
    5. View the member list again and verify that the member was removed:

      sh-4.2# etcdctl member list -w table
      Example output
      +------------------+---------+------------------------------+---------------------------+---------------------------+
      |        ID        | STATUS  |             NAME             |        PEER ADDRS         |       CLIENT ADDRS        |
      +------------------+---------+------------------------------+---------------------------+---------------------------+
      | 757b6793e2408b6c | started |  ip-10-0-164-97.ec2.internal |  https://10.0.164.97:2380 |  https://10.0.164.97:2379 |
      | ca8c2990a0aa29d1 | started | ip-10-0-154-204.ec2.internal | https://10.0.154.204:2380 | https://10.0.154.204:2379 |
      +------------------+---------+------------------------------+---------------------------+---------------------------+

      You can now exit the node shell.

      After you remove the member, the cluster might be unreachable for a short time while the remaining etcd instances reboot.

  2. Remove the old secrets for the unhealthy etcd member that was removed.

    1. List the secrets for the unhealthy etcd member that was removed.

      $ oc get secrets -n openshift-etcd | grep ip-10-0-131-183.ec2.internal (1)
      1 Pass in the name of the unhealthy etcd member that you took note of earlier in this procedure.

      There is a peer, serving, and metrics secret as shown in the following output:

      Example output
      etcd-peer-ip-10-0-131-183.ec2.internal              kubernetes.io/tls                     2      47m
      etcd-serving-ip-10-0-131-183.ec2.internal           kubernetes.io/tls                     2      47m
      etcd-serving-metrics-ip-10-0-131-183.ec2.internal   kubernetes.io/tls                     2      47m
    2. Delete the secrets for the unhealthy etcd member that was removed.

      1. Delete the peer secret:

        $ oc delete secret -n openshift-etcd etcd-peer-ip-10-0-131-183.ec2.internal
      2. Delete the serving secret:

        $ oc delete secret -n openshift-etcd etcd-serving-ip-10-0-131-183.ec2.internal
      3. Delete the metrics secret:

        $ oc delete secret -n openshift-etcd etcd-serving-metrics-ip-10-0-131-183.ec2.internal
  3. Delete and recreate the control plane machine. After this machine is recreated, a new revision is forced and etcd scales up automatically.

    If you are running installer-provisioned infrastructure, or you used the Machine API to create your machines, follow these steps. Otherwise, you must create the new master using the same method that was used to originally create it.

    1. Obtain the machine for the unhealthy member.

      In a terminal that has access to the cluster as a cluster-admin user, run the following command:

      $ oc get machines -n openshift-machine-api -o wide
      Example output
      NAME                                        PHASE     TYPE        REGION      ZONE         AGE     NODE                           PROVIDERID                              STATE
      clustername-8qw5l-master-0                  Running   m4.xlarge   us-east-1   us-east-1a   3h37m   ip-10-0-131-183.ec2.internal   aws:///us-east-1a/i-0ec2782f8287dfb7e   stopped (1)
      clustername-8qw5l-master-1                  Running   m4.xlarge   us-east-1   us-east-1b   3h37m   ip-10-0-154-204.ec2.internal   aws:///us-east-1b/i-096c349b700a19631   running
      clustername-8qw5l-master-2                  Running   m4.xlarge   us-east-1   us-east-1c   3h37m   ip-10-0-164-97.ec2.internal    aws:///us-east-1c/i-02626f1dba9ed5bba   running
      clustername-8qw5l-worker-us-east-1a-wbtgd   Running   m4.large    us-east-1   us-east-1a   3h28m   ip-10-0-129-226.ec2.internal   aws:///us-east-1a/i-010ef6279b4662ced   running
      clustername-8qw5l-worker-us-east-1b-lrdxb   Running   m4.large    us-east-1   us-east-1b   3h28m   ip-10-0-144-248.ec2.internal   aws:///us-east-1b/i-0cb45ac45a166173b   running
      clustername-8qw5l-worker-us-east-1c-pkg26   Running   m4.large    us-east-1   us-east-1c   3h28m   ip-10-0-170-181.ec2.internal   aws:///us-east-1c/i-06861c00007751b0a   running
      1 This is the control plane machine for the unhealthy node, ip-10-0-131-183.ec2.internal.
    2. Save the machine configuration to a file on your file system:

      $ oc get machine clustername-8qw5l-master-0 \ (1)
          -n openshift-machine-api \
          -o yaml \
          > new-master-machine.yaml
      1 Specify the name of the control plane machine for the unhealthy node.
    3. Edit the new-master-machine.yaml file that was created in the previous step to assign a new name and remove unnecessary fields.

      1. Remove the entire status section:

        status:
          addresses:
          - address: 10.0.131.183
            type: InternalIP
          - address: ip-10-0-131-183.ec2.internal
            type: InternalDNS
          - address: ip-10-0-131-183.ec2.internal
            type: Hostname
          lastUpdated: "2020-04-20T17:44:29Z"
          nodeRef:
            kind: Node
            name: ip-10-0-131-183.ec2.internal
            uid: acca4411-af0d-4387-b73e-52b2484295ad
          phase: Running
          providerStatus:
            apiVersion: awsproviderconfig.openshift.io/v1beta1
            conditions:
            - lastProbeTime: "2020-04-20T16:53:50Z"
              lastTransitionTime: "2020-04-20T16:53:50Z"
              message: machine successfully created
              reason: MachineCreationSucceeded
              status: "True"
              type: MachineCreation
            instanceId: i-0fdb85790d76d0c3f
            instanceState: stopped
            kind: AWSMachineProviderStatus
      2. Change the metadata.name field to a new name.

        It is recommended to keep the same base name as the old machine and change the ending number to the next available number. In this example, clustername-8qw5l-master-0 is changed to clustername-8qw5l-master-3.

        For example:

        apiVersion: machine.openshift.io/v1beta1
        kind: Machine
        metadata:
          ...
          name: clustername-8qw5l-master-3
          ...
      3. Remove the spec.providerID field:

          providerID: aws:///us-east-1a/i-0fdb85790d76d0c3f
      4. Remove the metadata.annotations and metadata.generation fields:

          annotations:
            machine.openshift.io/instance-state: running
          ...
          generation: 2
      5. Remove the metadata.resourceVersion and metadata.uid fields:

          resourceVersion: "13291"
          uid: a282eb70-40a2-4e89-8009-d05dd420d31a
    4. Delete the machine of the unhealthy member:

      $ oc delete machine -n openshift-machine-api clustername-8qw5l-master-0 (1)
      1 Specify the name of the control plane machine for the unhealthy node.
    5. Verify that the machine was deleted:

      $ oc get machines -n openshift-machine-api -o wide
      Example output
      NAME                                        PHASE     TYPE        REGION      ZONE         AGE     NODE                           PROVIDERID                              STATE
      clustername-8qw5l-master-1                  Running   m4.xlarge   us-east-1   us-east-1b   3h37m   ip-10-0-154-204.ec2.internal   aws:///us-east-1b/i-096c349b700a19631   running
      clustername-8qw5l-master-2                  Running   m4.xlarge   us-east-1   us-east-1c   3h37m   ip-10-0-164-97.ec2.internal    aws:///us-east-1c/i-02626f1dba9ed5bba   running
      clustername-8qw5l-worker-us-east-1a-wbtgd   Running   m4.large    us-east-1   us-east-1a   3h28m   ip-10-0-129-226.ec2.internal   aws:///us-east-1a/i-010ef6279b4662ced   running
      clustername-8qw5l-worker-us-east-1b-lrdxb   Running   m4.large    us-east-1   us-east-1b   3h28m   ip-10-0-144-248.ec2.internal   aws:///us-east-1b/i-0cb45ac45a166173b   running
      clustername-8qw5l-worker-us-east-1c-pkg26   Running   m4.large    us-east-1   us-east-1c   3h28m   ip-10-0-170-181.ec2.internal   aws:///us-east-1c/i-06861c00007751b0a   running
    6. Create the new machine using the new-master-machine.yaml file:

      $ oc apply -f new-master-machine.yaml
    7. Verify that the new machine has been created:

      $ oc get machines -n openshift-machine-api -o wide
      Example output
      NAME                                        PHASE          TYPE        REGION      ZONE         AGE     NODE                           PROVIDERID                              STATE
      clustername-8qw5l-master-1                  Running        m4.xlarge   us-east-1   us-east-1b   3h37m   ip-10-0-154-204.ec2.internal   aws:///us-east-1b/i-096c349b700a19631   running
      clustername-8qw5l-master-2                  Running        m4.xlarge   us-east-1   us-east-1c   3h37m   ip-10-0-164-97.ec2.internal    aws:///us-east-1c/i-02626f1dba9ed5bba   running
      clustername-8qw5l-master-3                  Provisioning   m4.xlarge   us-east-1   us-east-1a   85s     ip-10-0-133-53.ec2.internal    aws:///us-east-1a/i-015b0888fe17bc2c8   running (1)
      clustername-8qw5l-worker-us-east-1a-wbtgd   Running        m4.large    us-east-1   us-east-1a   3h28m   ip-10-0-129-226.ec2.internal   aws:///us-east-1a/i-010ef6279b4662ced   running
      clustername-8qw5l-worker-us-east-1b-lrdxb   Running        m4.large    us-east-1   us-east-1b   3h28m   ip-10-0-144-248.ec2.internal   aws:///us-east-1b/i-0cb45ac45a166173b   running
      clustername-8qw5l-worker-us-east-1c-pkg26   Running        m4.large    us-east-1   us-east-1c   3h28m   ip-10-0-170-181.ec2.internal   aws:///us-east-1c/i-06861c00007751b0a   running
      1 The new machine, clustername-8qw5l-master-3 is being created and is ready once the phase changes from Provisioning to Running.

      It might take a few minutes for the new machine to be created. The etcd cluster Operator will automatically sync when the machine or node returns to a healthy state.

Verification
  1. Verify that all etcd pods are running properly.

    In a terminal that has access to the cluster as a cluster-admin user, run the following command:

    $ oc get pods -n openshift-etcd | grep -v etcd-quorum-guard | grep etcd
    Example output
    etcd-ip-10-0-133-53.ec2.internal                 3/3     Running     0          7m49s
    etcd-ip-10-0-164-97.ec2.internal                 3/3     Running     0          123m
    etcd-ip-10-0-154-204.ec2.internal                3/3     Running     0          124m

    If the output from the previous command only lists two pods, you can manually force an etcd redeployment. In a terminal that has access to the cluster as a cluster-admin user, run the following command:

    $ oc patch etcd cluster -p='{"spec": {"forceRedeploymentReason": "recovery-'"$( date --rfc-3339=ns )"'"}}' --type=merge (1)
    1 The forceRedeploymentReason value must be unique, which is why a timestamp is appended.
  2. Verify that there are exactly three etcd members.

    1. Connect to the running etcd container, passing in the name of a pod that was not on the affected node:

      In a terminal that has access to the cluster as a cluster-admin user, run the following command:

      $ oc rsh -n openshift-etcd etcd-ip-10-0-154-204.ec2.internal
    2. View the member list:

      sh-4.2# etcdctl member list -w table
      Example output
      +------------------+---------+------------------------------+---------------------------+---------------------------+
      |        ID        | STATUS  |             NAME             |        PEER ADDRS         |       CLIENT ADDRS        |
      +------------------+---------+------------------------------+---------------------------+---------------------------+
      | 5eb0d6b8ca24730c | started |  ip-10-0-133-53.ec2.internal |  https://10.0.133.53:2380 |  https://10.0.133.53:2379 |
      | 757b6793e2408b6c | started |  ip-10-0-164-97.ec2.internal |  https://10.0.164.97:2380 |  https://10.0.164.97:2379 |
      | ca8c2990a0aa29d1 | started | ip-10-0-154-204.ec2.internal | https://10.0.154.204:2380 | https://10.0.154.204:2379 |
      +------------------+---------+------------------------------+---------------------------+---------------------------+

      If the output from the previous command lists more than three etcd members, you must carefully remove the unwanted member.

      Be sure to remove the correct etcd member; removing a good etcd member might lead to quorum loss.

Replacing an unhealthy etcd member whose etcd pod is crashlooping

This procedure details the steps to replace an etcd member that is unhealthy because the etcd pod is crashlooping.

Prerequisites
  • You have identified the unhealthy etcd member.

  • You have verified that the etcd pod is crashlooping.

  • You have access to the cluster as a user with the cluster-admin role.

  • You have taken an etcd backup.

    It is important to take an etcd backup before performing this procedure so that your cluster can be restored if you encounter any issues.

Procedure
  1. Stop the crashlooping etcd pod.

    1. Debug the node that is crashlooping.

      In a terminal that has access to the cluster as a cluster-admin user, run the following command:

      $ oc debug node/ip-10-0-131-183.ec2.internal (1)
      1 Replace this with the name of the unhealthy node.
    2. Change your root directory to the host:

      sh-4.2# chroot /host
    3. Move the existing etcd pod file out of the kubelet manifest directory:

      sh-4.2# mkdir /var/lib/etcd-backup
      sh-4.2# mv /etc/kubernetes/manifests/etcd-pod.yaml /var/lib/etcd-backup/
    4. Move the etcd data directory to a different location:

      sh-4.2# mv /var/lib/etcd/ /tmp

      You can now exit the node shell.

  2. Remove the unhealthy member.

    1. Choose a pod that is not on the affected node.

      In a terminal that has access to the cluster as a cluster-admin user, run the following command:

      $ oc get pods -n openshift-etcd | grep -v etcd-quorum-guard | grep etcd
      Example output
      etcd-ip-10-0-131-183.ec2.internal                2/3     Error       7          6h9m
      etcd-ip-10-0-164-97.ec2.internal                 3/3     Running     0          6h6m
      etcd-ip-10-0-154-204.ec2.internal                3/3     Running     0          6h6m
    2. Connect to the running etcd container, passing in the name of a pod that is not on the affected node.

      In a terminal that has access to the cluster as a cluster-admin user, run the following command:

      $ oc rsh -n openshift-etcd etcd-ip-10-0-154-204.ec2.internal
    3. View the member list:

      sh-4.2# etcdctl member list -w table
      Example output
      +------------------+---------+------------------------------+---------------------------+---------------------------+
      |        ID        | STATUS  |             NAME             |        PEER ADDRS         |       CLIENT ADDRS        |
      +------------------+---------+------------------------------+---------------------------+---------------------------+
      | 62bcf33650a7170a | started | ip-10-0-131-183.ec2.internal | https://10.0.131.183:2380 | https://10.0.131.183:2379 |
      | b78e2856655bc2eb | started |  ip-10-0-164-97.ec2.internal |  https://10.0.164.97:2380 |  https://10.0.164.97:2379 |
      | d022e10b498760d5 | started | ip-10-0-154-204.ec2.internal | https://10.0.154.204:2380 | https://10.0.154.204:2379 |
      +------------------+---------+------------------------------+---------------------------+---------------------------+

      Take note of the ID and the name of the unhealthy etcd member, because these values are needed later in the procedure.

    4. Remove the unhealthy etcd member by providing the ID to the etcdctl member remove command:

      sh-4.2# etcdctl member remove 62bcf33650a7170a
      Example output
      Member 62bcf33650a7170a removed from cluster ead669ce1fbfb346
    5. View the member list again and verify that the member was removed:

      sh-4.2# etcdctl member list -w table
      Example output
      +------------------+---------+------------------------------+---------------------------+---------------------------+
      |        ID        | STATUS  |             NAME             |        PEER ADDRS         |       CLIENT ADDRS        |
      +------------------+---------+------------------------------+---------------------------+---------------------------+
      | b78e2856655bc2eb | started |  ip-10-0-164-97.ec2.internal |  https://10.0.164.97:2380 |  https://10.0.164.97:2379 |
      | d022e10b498760d5 | started | ip-10-0-154-204.ec2.internal | https://10.0.154.204:2380 | https://10.0.154.204:2379 |
      +------------------+---------+------------------------------+---------------------------+---------------------------+

      You can now exit the node shell.

  3. Remove the old secrets for the unhealthy etcd member that was removed.

    1. List the secrets for the unhealthy etcd member that was removed.

      $ oc get secrets -n openshift-etcd | grep ip-10-0-131-183.ec2.internal (1)
      1 Pass in the name of the unhealthy etcd member that you took note of earlier in this procedure.

      There is a peer, serving, and metrics secret as shown in the following output:

      Example output
      etcd-peer-ip-10-0-131-183.ec2.internal              kubernetes.io/tls                     2      47m
      etcd-serving-ip-10-0-131-183.ec2.internal           kubernetes.io/tls                     2      47m
      etcd-serving-metrics-ip-10-0-131-183.ec2.internal   kubernetes.io/tls                     2      47m
    2. Delete the secrets for the unhealthy etcd member that was removed.

      1. Delete the peer secret:

        $ oc delete secret -n openshift-etcd etcd-peer-ip-10-0-131-183.ec2.internal
      2. Delete the serving secret:

        $ oc delete secret -n openshift-etcd etcd-serving-ip-10-0-131-183.ec2.internal
      3. Delete the metrics secret:

        $ oc delete secret -n openshift-etcd etcd-serving-metrics-ip-10-0-131-183.ec2.internal
  4. Force etcd redeployment.

    In a terminal that has access to the cluster as a cluster-admin user, run the following command:

    $ oc patch etcd cluster -p='{"spec": {"forceRedeploymentReason": "single-master-recovery-'"$( date --rfc-3339=ns )"'"}}' --type=merge (1)
    1 The forceRedeploymentReason value must be unique, which is why a timestamp is appended.

    When the etcd cluster Operator performs a redeployment, it ensures that all control plane nodes have a functioning etcd pod.

Verification
  • Verify that the new member is available and healthy.

    1. Connect to the running etcd container again.

      In a terminal that has access to the cluster as a cluster-admin user, run the following command:

      $ oc rsh -n openshift-etcd etcd-ip-10-0-154-204.ec2.internal
    2. Verify that all members are healthy:

      sh-4.2# etcdctl endpoint health
      Example output
      https://10.0.131.183:2379 is healthy: successfully committed proposal: took = 16.671434ms
      https://10.0.154.204:2379 is healthy: successfully committed proposal: took = 16.698331ms
      https://10.0.164.97:2379 is healthy: successfully committed proposal: took = 16.621645ms

Replacing an unhealthy bare metal etcd member whose machine is not running or whose node is not ready

This procedure details the steps to replace a bare metal etcd member that is unhealthy either because the machine is not running or because the node is not ready.

If you are running installer-provisioned infrastructure or you used the Machine API to create your machines, follow these steps. Otherwise you must create the new control plane node using the same method that was used to originally create it.

Prerequisites
  • You have identified the unhealthy bare metal etcd member.

  • You have verified that either the machine is not running or the node is not ready.

  • You have access to the cluster as a user with the cluster-admin role.

  • You have taken an etcd backup.

    You must take an etcd backup before performing this procedure so that your cluster can be restored if you encounter any issues.

Procedure
  1. Verify and remove the unhealthy member.

    1. Choose a pod that is not on the affected node:

      In a terminal that has access to the cluster as a cluster-admin user, run the following command:

      $ oc get pods -n openshift-etcd -o wide | grep etcd | grep -v guard
      Example output
      etcd-openshift-control-plane-0   5/5   Running   11   3h56m   192.168.10.9   openshift-control-plane-0  <none>           <none>
      etcd-openshift-control-plane-1   5/5   Running   0    3h54m   192.168.10.10   openshift-control-plane-1   <none>           <none>
      etcd-openshift-control-plane-2   5/5   Running   0    3h58m   192.168.10.11   openshift-control-plane-2   <none>           <none>
    2. Connect to the running etcd container, passing in the name of a pod that is not on the affected node:

      In a terminal that has access to the cluster as a cluster-admin user, run the following command:

      $ oc rsh -n openshift-etcd etcd-openshift-control-plane-0
    3. View the member list:

      sh-4.2# etcdctl member list -w table
      Example output
      +------------------+---------+--------------------+---------------------------+---------------------------+---------------------+
      | ID               | STATUS  | NAME                      | PEER ADDRS                  | CLIENT ADDRS                | IS LEARNER |
      +------------------+---------+--------------------+---------------------------+---------------------------+---------------------+
      | 7a8197040a5126c8 | started | openshift-control-plane-2 | https://192.168.10.11:2380/ | https://192.168.10.11:2379/ | false |
      | 8d5abe9669a39192 | started | openshift-control-plane-1 | https://192.168.10.10:2380/ | https://192.168.10.10:2379/ | false |
      | cc3830a72fc357f9 | started | openshift-control-plane-0 | https://192.168.10.9:2380/ | https://192.168.10.9:2379/   | false |
      +------------------+---------+--------------------+---------------------------+---------------------------+---------------------+

      Take note of the ID and the name of the unhealthy etcd member, because these values are required later in the procedure. The etcdctl endpoint health command will list the removed member until the replacement procedure is completed and the new member is added.

    4. Remove the unhealthy etcd member by providing the ID to the etcdctl member remove command:

      Be sure to remove the correct etcd member; removing a good etcd member might lead to quorum loss.

      sh-4.2# etcdctl member remove 7a8197040a5126c8
      Example output
      Member 7a8197040a5126c8 removed from cluster b23536c33f2cdd1b
    5. View the member list again and verify that the member was removed:

      sh-4.2# etcdctl member list -w table
      Example output
      +------------------+---------+--------------------+---------------------------+---------------------------+-------------------------+
      | ID               | STATUS  | NAME                      | PEER ADDRS                  | CLIENT ADDRS                | IS LEARNER |
      +------------------+---------+--------------------+---------------------------+---------------------------+-------------------------+
      | 7a8197040a5126c8 | started | openshift-control-plane-2 | https://192.168.10.11:2380/ | https://192.168.10.11:2379/ | false |
      | 8d5abe9669a39192 | started | openshift-control-plane-1 | https://192.168.10.10:2380/ | https://192.168.10.10:2379/ | false |
      +------------------+---------+--------------------+---------------------------+---------------------------+-------------------------+

      You can now exit the node shell.

      After you remove the member, the cluster might be unreachable for a short time while the remaining etcd instances reboot.

  2. Remove the old secrets for the unhealthy etcd member that was removed by running the following commands.

    1. List the secrets for the unhealthy etcd member that was removed.

      $ oc get secrets -n openshift-etcd | grep openshift-control-plane-2

      Pass in the name of the unhealthy etcd member that you took note of earlier in this procedure.

      There is a peer, serving, and metrics secret as shown in the following output:

      etcd-peer-openshift-control-plane-2             kubernetes.io/tls   2   134m
      etcd-serving-metrics-openshift-control-plane-2  kubernetes.io/tls   2   134m
      etcd-serving-openshift-control-plane-2          kubernetes.io/tls   2   134m
    2. Delete the secrets for the unhealthy etcd member that was removed.

      1. Delete the peer secret:

        $ oc delete secret etcd-peer-openshift-control-plane-2 -n openshift-etcd
        
        secret "etcd-peer-openshift-control-plane-2" deleted
      2. Delete the serving secret:

        $ oc delete secret etcd-serving-metrics-openshift-control-plane-2 -n openshift-etcd
        
        secret "etcd-serving-metrics-openshift-control-plane-2" deleted
      3. Delete the metrics secret:

        $ oc delete secret etcd-serving-openshift-control-plane-2 -n openshift-etcd
        
        secret "etcd-serving-openshift-control-plane-2" deleted
  3. Delete the control plane machine.

    If you are running installer-provisioned infrastructure, or you used the Machine API to create your machines, follow these steps. Otherwise, you must create the new control plane node using the same method that was used to originally create it.

    1. Obtain the machine for the unhealthy member.

      In a terminal that has access to the cluster as a cluster-admin user, run the following command:

      $ oc get machines -n openshift-machine-api -o wide
      Example output
      NAME                              PHASE     TYPE   REGION   ZONE   AGE     NODE                               PROVIDERID                                                                                              STATE
      examplecluster-control-plane-0    Running                          3h11m   openshift-control-plane-0   baremetalhost:///openshift-machine-api/openshift-control-plane-0/da1ebe11-3ff2-41c5-b099-0aa41222964e   externally provisioned (1)
      examplecluster-control-plane-1    Running                          3h11m   openshift-control-plane-1   baremetalhost:///openshift-machine-api/openshift-control-plane-1/d9f9acbc-329c-475e-8d81-03b20280a3e1   externally provisioned
      examplecluster-control-plane-2    Running                          3h11m   openshift-control-plane-2   baremetalhost:///openshift-machine-api/openshift-control-plane-2/3354bdac-61d8-410f-be5b-6a395b056135   externally provisioned
      examplecluster-compute-0          Running                          165m    openshift-compute-0         baremetalhost:///openshift-machine-api/openshift-compute-0/3d685b81-7410-4bb3-80ec-13a31858241f         provisioned
      examplecluster-compute-1          Running                          165m    openshift-compute-1         baremetalhost:///openshift-machine-api/openshift-compute-1/0fdae6eb-2066-4241-91dc-e7ea72ab13b9         provisioned
      1 This is the control plane machine for the unhealthy node, examplecluster-control-plane-2.
    2. Save the machine configuration to a file on your file system:

      $ oc get machine examplecluster-control-plane-2 \ (1)
          -n openshift-machine-api \
          -o yaml \
          > new-master-machine.yaml
      1 Specify the name of the control plane machine for the unhealthy node.
    3. Edit the new-master-machine.yaml file that was created in the previous step to assign a new name and remove unnecessary fields.

      1. Remove the entire status section:

        status:
          addresses:
          - address: ""
            type: InternalIP
          - address: fe80::4adf:37ff:feb0:8aa1%ens1f1.373
            type: InternalDNS
          - address: fe80::4adf:37ff:feb0:8aa1%ens1f1.371
            type: Hostname
          lastUpdated: "2020-04-20T17:44:29Z"
          nodeRef:
            kind: Machine
            name: fe80::4adf:37ff:feb0:8aa1%ens1f1.372
            uid: acca4411-af0d-4387-b73e-52b2484295ad
          phase: Running
          providerStatus:
            apiVersion: machine.openshift.io/v1beta1
            conditions:
            - lastProbeTime: "2020-04-20T16:53:50Z"
              lastTransitionTime: "2020-04-20T16:53:50Z"
              message: machine successfully created
              reason: MachineCreationSucceeded
              status: "True"
              type: MachineCreation
            instanceId: i-0fdb85790d76d0c3f
            instanceState: stopped
            kind: Machine
  4. Change the metadata.name field to a new name.

    It is recommended to keep the same base name as the old machine and change the ending number to the next available number. In this example, examplecluster-control-plane-2 is changed to examplecluster-control-plane-3.

    For example:

    apiVersion: machine.openshift.io/v1beta1
    kind: Machine
    metadata:
      ...
      name: examplecluster-control-plane-3
      ...
    1. Remove the spec.providerID field:

        providerID: baremetalhost:///openshift-machine-api/openshift-control-plane-2/3354bdac-61d8-410f-be5b-6a395b056135
    2. Remove the metadata.annotations and metadata.generation fields:

        annotations:
          machine.openshift.io/instance-state: externally provisioned
        ...
        generation: 2
    3. Remove the spec.conditions, spec.lastUpdated, spec.nodeRef and spec.phase fields:

        lastTransitionTime: "2022-08-03T08:40:36Z"
      message: 'Drain operation currently blocked by: [{Name:EtcdQuorumOperator Owner:clusteroperator/etcd}]'
      reason: HookPresent
      severity: Warning
      status: "False"
      
      type: Drainable
      lastTransitionTime: "2022-08-03T08:39:55Z"
      status: "True"
      type: InstanceExists
      
      lastTransitionTime: "2022-08-03T08:36:37Z"
      status: "True"
      type: Terminable
      lastUpdated: "2022-08-03T08:40:36Z"
      nodeRef:
      kind: Node
      name: openshift-control-plane-2
      uid: 788df282-6507-4ea2-9a43-24f237ccbc3c
      phase: Running
  5. Ensure that the Bare Metal Operator is available by running the following command:

    $ oc get clusteroperator baremetal
    Example output
    NAME        VERSION   AVAILABLE   PROGRESSING   DEGRADED   SINCE   MESSAGE
    baremetal   4.11.3    True        False         False      3d15h
  6. Delete the machine of the unhealthy member using this command:

    $ oc delete machine -n openshift-machine-api examplecluster-control-plane-2

    If deletion of the machine is delayed for any reason or the command is obstructed and delayed, you can force deletion by removing the machine object finalizer field.

    Do not interrupt machine deletion by pressing Ctrl+c. You must allow the command to proceed to completion. Open a new terminal window to edit and delete the finalizer fields.

    $ oc edit machine -n openshift-machine-api examplecluster-control-plane-2
    1. Find and delete the fields:

      finalizers:
      - machine.machine.openshift.io

      Save your changes:

      machine.machine.openshift.io/examplecluster-control-plane-2 edited
    2. Verify the machine was deleted by running the following command:

      $ oc get machines -n openshift-machine-api -o wide
      Example output
      NAME                              PHASE     TYPE   REGION   ZONE   AGE     NODE                                 PROVIDERID                                                                                       STATE
      examplecluster-control-plane-0    Running                          3h11m   openshift-control-plane-0   baremetalhost:///openshift-machine-api/openshift-control-plane-0/da1ebe11-3ff2-41c5-b099-0aa41222964e   externally provisioned
      examplecluster-control-plane-1    Running                          3h11m   openshift-control-plane-1   baremetalhost:///openshift-machine-api/openshift-control-plane-1/d9f9acbc-329c-475e-8d81-03b20280a3e1   externally provisioned
      examplecluster-compute-0          Running                          165m    openshift-compute-0         baremetalhost:///openshift-machine-api/openshift-compute-0/3d685b81-7410-4bb3-80ec-13a31858241f         provisioned
      examplecluster-compute-1          Running                          165m    openshift-compute-1         baremetalhost:///openshift-machine-api/openshift-compute-1/0fdae6eb-2066-4241-91dc-e7ea72ab13b9         provisioned
  7. Remove the old BareMetalHost object with this command:

    $ oc delete bmh openshift-control-plane-2 -n openshift-machine-api
    Example output
    baremetalhost.metal3.io "openshift-control-plane-2" deleted

    After you remove the BareMetalHost and Machine objects, then the Machine controller automatically deletes the Node object.

    If, after deletion of the BareMetalHost object, the machine node requires excessive time for deletion, the machine node can be deleted using:

    $ oc delete node openshift-control-plane-2
    
    node "openshift-control-plane-2" deleted

    Verify the node has been deleted:

    $ oc get nodes
    
    NAME                     STATUS ROLES   AGE   VERSION
    openshift-control-plane-0 Ready master 3h24m v1.24.0+9546431
    openshift-control-plane-1 Ready master 3h24m v1.24.0+9546431
    openshift-compute-0       Ready worker 176m v1.24.0+9546431
    openshift-compute-1       Ready worker 176m v1.24.0+9546431
  8. Create the new BareMetalHost object and the secret to store the BMC credentials:

    $ cat <<EOF | oc apply -f -
    apiVersion: v1
    kind: Secret
    metadata:
      name: openshift-control-plane-2-bmc-secret
      namespace: openshift-machine-api
    data:
      password: <password>
      username: <username>
    type: Opaque
    ---
    apiVersion: metal3.io/v1alpha1
    kind: BareMetalHost
    metadata:
      name: openshift-control-plane-2
      namespace: openshift-machine-api
    spec:
      automatedCleaningMode: disabled
      bmc:
        address: redfish://10.46.61.18:443/redfish/v1/Systems/1
        credentialsName: openshift-control-plane-2-bmc-secret
        disableCertificateVerification: true
      bootMACAddress: 48:df:37:b0:8a:a0
      bootMode: UEFI
      externallyProvisioned: false
      online: true
      rootDeviceHints:
        deviceName: /dev/sda
      userData:
        name: master-user-data-managed
        namespace: openshift-machine-api
    EOF

    The username and password can be found from the other bare metal host’s secrets. The protocol to use in bmc:address can be taken from other bmh objects.

    If you reuse the BareMetalHost object definition from an existing control plane host, do not leave the externallyProvisioned field set to true.

    Existing control plane BareMetalHost objects may have the externallyProvisioned flag set to true if they were provisioned by the OKD installation program.

    After the inspection is complete, the BareMetalHost object is created and available to be provisioned.

  9. Verify the creation process using available BareMetalHost objects:

    $ oc get bmh -n openshift-machine-api
    
    NAME                      STATE                  CONSUMER                      ONLINE ERROR   AGE
    openshift-control-plane-0 externally provisioned examplecluster-control-plane-0 true         4h48m
    openshift-control-plane-1 externally provisioned examplecluster-control-plane-1 true         4h48m
    openshift-control-plane-2 available              examplecluster-control-plane-3 true         47m
    openshift-compute-0       provisioned            examplecluster-compute-0       true         4h48m
    openshift-compute-1       provisioned            examplecluster-compute-1       true         4h48m
    1. Create the new control plane machine using the new-master-machine.yaml file:

      $ oc apply -f new-master-machine.yaml
    2. Verify that the new machine has been created:

      $ oc get machines -n openshift-machine-api -o wide
      Example output
      NAME                                   PHASE     TYPE   REGION   ZONE   AGE     NODE                              PROVIDERID                                                                                            STATE
      examplecluster-control-plane-0         Running                          3h11m   openshift-control-plane-0   baremetalhost:///openshift-machine-api/openshift-control-plane-0/da1ebe11-3ff2-41c5-b099-0aa41222964e   externally provisioned (1)
      examplecluster-control-plane-1         Running                          3h11m   openshift-control-plane-1   baremetalhost:///openshift-machine-api/openshift-control-plane-1/d9f9acbc-329c-475e-8d81-03b20280a3e1   externally provisioned
      examplecluster-control-plane-2         Running                          3h11m   openshift-control-plane-2   baremetalhost:///openshift-machine-api/openshift-control-plane-2/3354bdac-61d8-410f-be5b-6a395b056135   externally provisioned
      examplecluster-compute-0               Running                          165m    openshift-compute-0         baremetalhost:///openshift-machine-api/openshift-compute-0/3d685b81-7410-4bb3-80ec-13a31858241f         provisioned
      examplecluster-compute-1               Running                          165m    openshift-compute-1         baremetalhost:///openshift-machine-api/openshift-compute-1/0fdae6eb-2066-4241-91dc-e7ea72ab13b9         provisioned
      1 The new machine, clustername-8qw5l-master-3 is being created and is ready after the phase changes from Provisioning to Running.

      It should take a few minutes for the new machine to be created. The etcd cluster Operator will automatically sync when the machine or node returns to a healthy state.

    3. Verify that the bare metal host becomes provisioned and no error reported by running the following command:

      $ oc get bmh -n openshift-machine-api
      Example output
      $ oc get bmh -n openshift-machine-api
      NAME                      STATE                  CONSUMER                       ONLINE ERROR AGE
      openshift-control-plane-0 externally provisioned examplecluster-control-plane-0 true         4h48m
      openshift-control-plane-1 externally provisioned examplecluster-control-plane-1 true         4h48m
      openshift-control-plane-2 provisioned            examplecluster-control-plane-3 true          47m
      openshift-compute-0       provisioned            examplecluster-compute-0       true         4h48m
      openshift-compute-1       provisioned            examplecluster-compute-1       true         4h48m
    4. Verify that the new node is added and in a ready state by running this command:

      $ oc get nodes
      Example output
      $ oc get nodes
      NAME                     STATUS ROLES   AGE   VERSION
      openshift-control-plane-0 Ready master 4h26m v1.24.0+9546431
      openshift-control-plane-1 Ready master 4h26m v1.24.0+9546431
      openshift-control-plane-2 Ready master 12m   v1.24.0+9546431
      openshift-compute-0       Ready worker 3h58m v1.24.0+9546431
      openshift-compute-1       Ready worker 3h58m v1.24.0+9546431
Verification
  1. Verify that all etcd pods are running properly.

    In a terminal that has access to the cluster as a cluster-admin user, run the following command:

    $ oc get pods -n openshift-etcd -o wide | grep etcd | grep -v guard
    Example output
    etcd-openshift-control-plane-0      5/5     Running     0     105m
    etcd-openshift-control-plane-1      5/5     Running     0     107m
    etcd-openshift-control-plane-2      5/5     Running     0     103m

    If the output from the previous command only lists two pods, you can manually force an etcd redeployment. In a terminal that has access to the cluster as a cluster-admin user, run the following command:

    $ oc patch etcd cluster -p='{"spec": {"forceRedeploymentReason": "recovery-'"$( date --rfc-3339=ns )"'"}}' --type=merge (1)
    1 The forceRedeploymentReason value must be unique, which is why a timestamp is appended.

    To verify there are exactly three etcd members, connect to the running etcd container, passing in the name of a pod that was not on the affected node. In a terminal that has access to the cluster as a cluster-admin user, run the following command:

    $ oc rsh -n openshift-etcd etcd-openshift-control-plane-0
  2. View the member list:

    sh-4.2# etcdctl member list -w table
    Example output
    +------------------+---------+--------------------+---------------------------+---------------------------+-----------------+
    |        ID        | STATUS  |        NAME        |        PEER ADDRS         |       CLIENT ADDRS        |    IS LEARNER    |
    +------------------+---------+--------------------+---------------------------+---------------------------+-----------------+
    | 7a8197040a5126c8 | started | openshift-control-plane-2 | https://192.168.10.11:2380 | https://192.168.10.11:2379 |   false |
    | 8d5abe9669a39192 | started | openshift-control-plane-1 | https://192.168.10.10:2380 | https://192.168.10.10:2379 |   false |
    | cc3830a72fc357f9 | started | openshift-control-plane-0 | https://192.168.10.9:2380 | https://192.168.10.9:2379 |     false |
    +------------------+---------+--------------------+---------------------------+---------------------------+-----------------+

    If the output from the previous command lists more than three etcd members, you must carefully remove the unwanted member.

  3. Verify that all etcd members are healthy by running the following command:

    # etcdctl endpoint health --cluster
    Example output
    https://192.168.10.10:2379 is healthy: successfully committed proposal: took = 8.973065ms
    https://192.168.10.9:2379 is healthy: successfully committed proposal: took = 11.559829ms
    https://192.168.10.11:2379 is healthy: successfully committed proposal: took = 11.665203ms
  4. Validate that all nodes are at the latest revision by running the following command:

    $ oc get etcd -o=jsonpath='{range.items[0].status.conditions[?(@.type=="NodeInstallerProgressing")]}{.reason}{"\n"}{.message}{"\n"}'
    AllNodesAtLatestRevision