Backup and restore

OpenShift Container Platform 4.5

Backing up and restoring your OpenShift Container Platform cluster

Red Hat OpenShift Documentation Team

Abstract

This document provides instructions for backing up your cluster's data and for recovering from various disaster scenarios.

Chapter 1. Backing up etcd

etcd is the key-value store for OpenShift Container Platform, which persists the state of all resource objects.

Back up your cluster’s etcd data regularly and store in a secure location ideally outside the OpenShift Container Platform environment. Do not take an etcd backup before the first certificate rotation completes, which occurs 24 hours after installation, otherwise the backup will contain expired certificates. It is also recommended to take etcd backups during non-peak usage hours, as it is a blocking action.

Be sure to take an etcd backup after you upgrade your cluster. This is important because when you restore your cluster, you must use an etcd backup that was taken from the same z-stream release. For example, an OpenShift Container Platform 4.5.2 cluster must use an etcd backup that was taken from 4.5.2.

Important

Back up your cluster’s etcd data by performing a single invocation of the backup script on a master host. Do not take a backup for each master host.

After you have an etcd backup, you can restore to a previous cluster state.

You can perform the etcd data backup process on any master host that has a running etcd instance.

1.1. Backing up etcd data

Follow these steps to back up etcd data by creating an etcd snapshot and backing up the resources for the static pods. This backup can be saved and used at a later time if you need to restore etcd.

Important

Only save a backup from a single master host. Do not take a backup from each master host in the cluster.

Prerequisites

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

  • You have checked whether the cluster-wide proxy is enabled.

    Tip

    You can check whether the proxy is enabled by reviewing the output of oc get proxy cluster -o yaml. The proxy is enabled if the httpProxy, httpsProxy, and noProxy fields have values set.

Procedure

  1. Start a debug session for a master node: 

    $ oc debug node/<node_name>

  2. Change your root directory to the host: 

    sh-4.2# chroot /host
  3. If the cluster-wide proxy is enabled, be sure that you have exported the NO_PROXY, HTTP_PROXY, and HTTPS_PROXY environment variables.

  4. Run the cluster-backup.sh script and pass in the location to save the backup to.

    Tip

    The cluster-backup.sh script is maintained as a component of the etcd Cluster Operator and is a wrapper around the etcdctl snapshot save command. 

    sh-4.4# /usr/local/bin/cluster-backup.sh /home/core/assets/backup

    Example script output

    1bf371f1b5a483927cd01bb593b0e12cff406eb8d7d0acf4ab079c36a0abd3f7
etcdctl version: 3.3.18
API version: 3.3
found latest kube-apiserver-pod: /etc/kubernetes/static-pod-resources/kube-apiserver-pod-7
found latest kube-controller-manager-pod: /etc/kubernetes/static-pod-resources/kube-controller-manager-pod-8
found latest kube-scheduler-pod: /etc/kubernetes/static-pod-resources/kube-scheduler-pod-6
found latest etcd-pod: /etc/kubernetes/static-pod-resources/etcd-pod-2
Snapshot saved at /home/core/assets/backup/snapshot_2020-03-18_220218.db
snapshot db and kube resources are successfully saved to /home/core/assets/backup

    In this example, two files are created in the /home/core/assets/backup/ directory on the master host:

    • snapshot_<datetimestamp>.db: This file is the etcd snapshot.

    • static_kuberesources_<datetimestamp>.tar.gz: This file contains the resources for the static pods. If etcd encryption is enabled, it also contains the encryption keys for the etcd snapshot.

      Note

      If etcd encryption is enabled, it is recommended to store this second file separately from the etcd snapshot for security reasons. However, this file is required in order to restore from the etcd snapshot.

      Keep in mind that etcd encryption only encrypts values, not keys. This means that resource types, namespaces, and object names are unencrypted.

Chapter 2. Replacing an unhealthy etcd member

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.

Note

If you have lost the majority of your master 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 master 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.

2.1. Prerequisites

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

2.2. 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.

2.3. 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.

Note

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   v1.18.3 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 master 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   v1.18.3
ip-10-0-164-97.ec2.internal    Ready    master   6h13m   v1.18.3
ip-10-0-154-204.ec2.internal   Ready    master   6h13m   v1.18.3

    2. Check whether the status of an etcd pod is either Error or CrashloopBackoff: 

      $ oc get pods -n openshift-etcd | 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.

2.4. Replacing the unhealthy etcd member

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

2.4.1. 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.

    Important

    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 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.

    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 baa565c8919b060e

    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.

  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 master 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 master 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 master 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. Update the metadata.selfLink field to use the new machine name from the previous step. 

        apiVersion: machine.openshift.io/v1beta1
kind: Machine
metadata:
  ...
  selfLink: /apis/machine.openshift.io/v1beta1/namespaces/openshift-machine-api/machines/clustername-8qw5l-master-3
  ...

      4. Remove the spec.providerID field: 

          providerID: aws:///us-east-1a/i-0fdb85790d76d0c3f

      5. Remove the metadata.annotations and metadata.generation fields: 

          annotations:
    machine.openshift.io/instance-state: running
  ...
  generation: 2

      6. 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 master 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 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.

      Warning

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

2.4.2. 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.

    Important

    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 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 master 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 --cluster

      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

Chapter 3. Shutting down the cluster gracefully

This document describes the process to gracefully shut down your cluster. You might need to temporarily shut down your cluster for maintenance reasons, or to save on resource costs.

3.1. Prerequisites

  • Take an etcd backup prior to shutting down the cluster.

3.2. Shutting down the cluster

You can shut down your cluster in a graceful manner so that it can be restarted at a later date.

Prerequisites

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

  • You have taken an etcd backup.

    Important

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

Procedure

  1. Shut down all of the nodes in the cluster. You can do this from your cloud provider’s web console, or you can use the below commands:

    1. Obtain the list of nodes: 

      $ nodes=$(oc get nodes -o jsonpath='{.items[*].metadata.name}')

    2. Shut down all of the nodes: 

      $ for node in ${nodes[@]}
do
    echo "==== Shut down $node ===="
    ssh core@$node sudo shutdown -h 1
done

      Shutting down the nodes using one of these methods allows pods to terminate gracefully, which reduces the chance for data corruption.

      Note

      It is not necessary to drain master nodes of the standard pods that ship with OpenShift Container Platform prior to shutdown.

      Cluster administrators are responsible for ensuring a clean restart of their own workloads after the cluster is restarted. If you drained master nodes prior to shutdown because of custom workloads, you must mark the master nodes as schedulable before the cluster will be functional again after restart.

  2. Shut off any cluster dependencies that are no longer needed, such as external storage or an LDAP server. Be sure to consult your vendor’s documentation before doing so.

Additional resources

Chapter 4. Restarting the cluster gracefully

This document describes the process to restart your cluster after a graceful shutdown.

Even though the cluster is expected to be functional after the restart, the cluster might not recover due to unexpected conditions, for example:

  • etcd data corruption during shutdown
  • Node failure due to hardware
  • Network connectivity issues

If your cluster fails to recover, follow the steps to restore to a previous cluster state.

4.1. Prerequisites

4.2. Restarting the cluster

You can restart your cluster after it has been shut down gracefully.

Prerequisites

  • You have access to the cluster as a user with the cluster-admin role.
  • This procedure assumes that you gracefully shut down the cluster.

Procedure

  1. Power on any cluster dependencies, such as external storage or an LDAP server.

  2. Start all cluster machines.

    Use the appropriate method for your cloud environment to start the machines, for example, from your cloud provider’s web console.

    Wait approximately 10 minutes before continuing to check the status of master nodes.

  3. Verify that all master nodes are ready. 

    $ oc get nodes -l node-role.kubernetes.io/master

    The master nodes are ready if the status is Ready, as shown in the following output: 

    NAME                           STATUS   ROLES    AGE   VERSION
ip-10-0-168-251.ec2.internal   Ready    master   75m   v1.18.3
ip-10-0-170-223.ec2.internal   Ready    master   75m   v1.18.3
ip-10-0-211-16.ec2.internal    Ready    master   75m   v1.18.3

  4. If the master nodes are not ready, then check whether there are any pending certificate signing requests (CSRs) that must be approved.

    1. Get the list of current CSRs: 

      $ oc get csr

    2. Review the details of a CSR to verify that it is valid: 

      $ oc describe csr <csr_name> 1
      1
      <csr_name> is the name of a CSR from the list of current CSRs.

    3. Approve each valid CSR: 

      $ oc adm certificate approve <csr_name>

  5. After the master nodes are ready, verify that all worker nodes are ready. 

    $ oc get nodes -l node-role.kubernetes.io/worker

    The worker nodes are ready if the status is Ready, as shown in the following output: 

    NAME                           STATUS   ROLES    AGE   VERSION
ip-10-0-179-95.ec2.internal    Ready    worker   64m   v1.18.3
ip-10-0-182-134.ec2.internal   Ready    worker   64m   v1.18.3
ip-10-0-250-100.ec2.internal   Ready    worker   64m   v1.18.3

  6. If the worker nodes are not ready, then check whether there are any pending certificate signing requests (CSRs) that must be approved.

    1. Get the list of current CSRs: 

      $ oc get csr

    2. Review the details of a CSR to verify that it is valid: 

      $ oc describe csr <csr_name> 1
      1
      <csr_name> is the name of a CSR from the list of current CSRs.

    3. Approve each valid CSR: 

      $ oc adm certificate approve <csr_name>

  7. Verify that the cluster started properly.

    1. Check that there are no degraded cluster Operators. 

      $ oc get clusteroperators

      Check that there are no cluster Operators with the DEGRADED condition set to True. 

      NAME                                       VERSION   AVAILABLE   PROGRESSING   DEGRADED   SINCE
authentication                             4.5.0     True        False         False      59m
cloud-credential                           4.5.0     True        False         False      85m
cluster-autoscaler                         4.5.0     True        False         False      73m
config-operator                            4.5.0     True        False         False      73m
console                                    4.5.0     True        False         False      62m
csi-snapshot-controller                    4.5.0     True        False         False      66m
dns                                        4.5.0     True        False         False      76m
etcd                                       4.5.0     True        False         False      76m
...

    2. Check that all nodes are in the Ready state: 

      $ oc get nodes

      Check that the status for all nodes is Ready. 

      NAME                           STATUS   ROLES    AGE   VERSION
ip-10-0-168-251.ec2.internal   Ready    master   82m   v1.18.3
ip-10-0-170-223.ec2.internal   Ready    master   82m   v1.18.3
ip-10-0-179-95.ec2.internal    Ready    worker   70m   v1.18.3
ip-10-0-182-134.ec2.internal   Ready    worker   70m   v1.18.3
ip-10-0-211-16.ec2.internal    Ready    master   82m   v1.18.3
ip-10-0-250-100.ec2.internal   Ready    worker   69m   v1.18.3

If the cluster did not start properly, you might need to restore your cluster using an etcd backup.

Additional resources

Chapter 5. Disaster recovery

5.1. About disaster recovery

The disaster recovery documentation provides information for administrators on how to recover from several disaster situations that might occur with their OpenShift Container Platform cluster. As an administrator, you might need to follow one or more of the following procedures in order to return your cluster to a working state.

Important

Disaster recovery requires you to have at least one healthy master host.

Restoring to a previous cluster state

This solution handles situations where you want to restore your cluster to a previous state, for example, if an administrator deletes something critical. This also includes situations where you have lost the majority of your master hosts, leading to etcd quorum loss and the cluster going offline. As long as you have taken an etcd backup, you can follow this procedure to restore your cluster to a previous state.

If applicable, you might also need to recover from expired control plane certificates.

Note

If you have a majority of your masters still available and have an etcd quorum, then follow the procedure to replace a single unhealthy etcd member.

Recovering from expired control plane certificates
This solution handles situations where your control plane certificates have expired. For example, if you shut down your cluster before the first certificate rotation, which occurs 24 hours after installation, your certificates will not be rotated and will expire. You can follow this procedure to recover from expired control plane certificates.

5.2. Recovering from lost master hosts

As of OpenShift Container Platform 4.4, follow the procedure to restore to a previous cluster state in order to recover from lost master hosts.

Note

If you have a majority of your masters still available and have an etcd quorum, then follow the procedure to replace a single unhealthy etcd member.

5.3. Restoring to a previous cluster state

To restore the cluster to a previous state, you must have previously backed up etcd data by creating a snapshot. You will use this snapshot to restore the cluster state.

5.3.1. Restoring to a previous cluster state

You can use a saved etcd backup to restore back to a previous cluster state. You use the etcd backup to restore a single control plane host. Then the etcd cluster Operator handles scaling to the remaining master hosts.

Important

When you restore your cluster, you must use an etcd backup that was taken from the same z-stream release. For example, an OpenShift Container Platform 4.5.2 cluster must use an etcd backup that was taken from 4.5.2.

Prerequisites

  • Access to the cluster as a user with the cluster-admin role.
  • A healthy master host to use as the recovery host.
  • SSH access to master hosts.
  • A backup directory containing both the etcd snapshot and the resources for the static pods, which were from the same backup. The file names in the directory must be in the following formats: snapshot_<datetimestamp>.db and static_kuberesources_<datetimestamp>.tar.gz.

Procedure

  1. Select a control plane host to use as the recovery host. This is the host that you will run the restore operation on.

  2. Establish SSH connectivity to each of the control plane nodes, including the recovery host.

    The Kubernetes API server becomes inaccessible after the restore process starts, so you cannot access the control plane nodes. For this reason, it is recommended to establish SSH connectivity to each control plane host in a separate terminal.

    Important

    If you do not complete this step, you will not be able to access the master hosts to complete the restore procedure, and you will be unable to recover your cluster from this state.

  3. Copy the etcd backup directory to the recovery control plane host.

    This procedure assumes that you copied the backup directory containing the etcd snapshot and the resources for the static pods to the /home/core/ directory of your recovery control plane host.

  4. Stop the static pods on all other control plane nodes.

    Note

    It is not required to manually stop the pods on the recovery host. The recovery script will stop the pods on the recovery host.

    1. Access a control plane host that is not the recovery host.

    2. Move the existing etcd pod file out of the kubelet manifest directory: 

      [core@ip-10-0-154-194 ~]$ sudo mv /etc/kubernetes/manifests/etcd-pod.yaml /tmp

    3. Verify that the etcd pods are stopped. 

      [core@ip-10-0-154-194 ~]$ sudo crictl ps | grep etcd | grep -v operator

      The output of this command should be empty. If it is not empty, wait a few minutes and check again.

    4. Move the existing Kubernetes API server pod file out of the kubelet manifest directory: 

      [core@ip-10-0-154-194 ~]$ sudo mv /etc/kubernetes/manifests/kube-apiserver-pod.yaml /tmp

    5. Verify that the Kubernetes API server pods are stopped. 

      [core@ip-10-0-154-194 ~]$ sudo crictl ps | grep kube-apiserver | grep -v operator

      The output of this command should be empty. If it is not empty, wait a few minutes and check again.

    6. Move the etcd data directory to a different location: 

      [core@ip-10-0-154-194 ~]$ sudo mv /var/lib/etcd/ /tmp
    7. Repeat this step on each of the other master hosts that is not the recovery host.
  5. Access the recovery control plane host.

  6. If the cluster-wide proxy is enabled, be sure that you have exported the NO_PROXY, HTTP_PROXY, and HTTPS_PROXY environment variables.

    Tip

    You can check whether the proxy is enabled by reviewing the output of oc get proxy cluster -o yaml. The proxy is enabled if the httpProxy, httpsProxy, and noProxy fields have values set.

  7. Run the restore script on the recovery control plane host and pass in the path to the etcd backup directory: 

    [core@ip-10-0-143-125 ~]$ sudo -E /usr/local/bin/cluster-restore.sh /home/core/backup

    Example script output

    ...stopping kube-scheduler-pod.yaml
...stopping kube-controller-manager-pod.yaml
...stopping etcd-pod.yaml
...stopping kube-apiserver-pod.yaml
Waiting for container etcd to stop
.complete
Waiting for container etcdctl to stop
.............................complete
Waiting for container etcd-metrics to stop
complete
Waiting for container kube-controller-manager to stop
complete
Waiting for container kube-apiserver to stop
..........................................................................................complete
Waiting for container kube-scheduler to stop
complete
Moving etcd data-dir /var/lib/etcd/member to /var/lib/etcd-backup
starting restore-etcd static pod
starting kube-apiserver-pod.yaml
static-pod-resources/kube-apiserver-pod-7/kube-apiserver-pod.yaml
starting kube-controller-manager-pod.yaml
static-pod-resources/kube-controller-manager-pod-7/kube-controller-manager-pod.yaml
starting kube-scheduler-pod.yaml
static-pod-resources/kube-scheduler-pod-8/kube-scheduler-pod.yaml

  8. Restart the kubelet service on all master hosts.

    1. From the recovery host, run the following command: 

      [core@ip-10-0-143-125 ~]$ sudo systemctl restart kubelet.service
    2. Repeat this step on all other master hosts.

  9. Verify that the single member control plane has started successfully.

    1. From the recovery host, verify that the etcd container is running. 

      [core@ip-10-0-143-125 ~]$ sudo crictl ps | grep etcd | grep -v operator

      Example output

      3ad41b7908e32       36f86e2eeaaffe662df0d21041eb22b8198e0e58abeeae8c743c3e6e977e8009                                                         About a minute ago   Running             etcd                                          0                   7c05f8af362f0

    2. From the recovery host, verify that the etcd pod is running. 

      [core@ip-10-0-143-125 ~]$ oc get pods -n openshift-etcd | grep etcd
      Note

      If you attempt to run oc login prior to running this command and receive the following error, wait a few moments for the authentication controllers to start and try again. 

      Unable to connect to the server: EOF

      Example output

      NAME                                             READY   STATUS      RESTARTS   AGE
etcd-ip-10-0-143-125.ec2.internal                1/1     Running     1          2m47s

      If the status is Pending, or the output lists more than one running etcd pod, wait a few minutes and check again.

  10. 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": "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, the existing nodes are started with new pods similar to the initial bootstrap scale up.

  11. Verify all nodes are updated to the latest revision.

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

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

    Review the NodeInstallerProgressing status condition for etcd to verify that all nodes are at the latest revision. The output shows AllNodesAtLatestRevision upon successful update: 

    AllNodesAtLatestRevision
3 nodes are at revision 7 1
    1
    In this example, the latest revision number is 7.

    If the output includes multiple revision numbers, such as 2 nodes are at revision 6; 1 nodes are at revision 7, this means that the update is still in progress. Wait a few minutes and try again.

  12. After etcd is redeployed, force new rollouts for the control plane. The Kubernetes API server will reinstall itself on the other nodes because the kubelet is connected to API servers using an internal load balancer.

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

    1. Update the kubeapiserver: 

      $ oc patch kubeapiserver cluster -p='{"spec": {"forceRedeploymentReason": "recovery-'"$( date --rfc-3339=ns )"'"}}' --type=merge

      Verify all nodes are updated to the latest revision. 

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

      Review the NodeInstallerProgressing status condition to verify that all nodes are at the latest revision. The output shows AllNodesAtLatestRevision upon successful update: 

      AllNodesAtLatestRevision
3 nodes are at revision 7 1
      1
      In this example, the latest revision number is 7.

      If the output includes multiple revision numbers, such as 2 nodes are at revision 6; 1 nodes are at revision 7, this means that the update is still in progress. Wait a few minutes and try again.

    2. Update the kubecontrollermanager: 

      $ oc patch kubecontrollermanager cluster -p='{"spec": {"forceRedeploymentReason": "recovery-'"$( date --rfc-3339=ns )"'"}}' --type=merge

      Verify all nodes are updated to the latest revision. 

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

      Review the NodeInstallerProgressing status condition to verify that all nodes are at the latest revision. The output shows AllNodesAtLatestRevision upon successful update: 

      AllNodesAtLatestRevision
3 nodes are at revision 7 1
      1
      In this example, the latest revision number is 7.

      If the output includes multiple revision numbers, such as 2 nodes are at revision 6; 1 nodes are at revision 7, this means that the update is still in progress. Wait a few minutes and try again.

    3. Update the kubescheduler: 

      $ oc patch kubescheduler cluster -p='{"spec": {"forceRedeploymentReason": "recovery-'"$( date --rfc-3339=ns )"'"}}' --type=merge

      Verify all nodes are updated to the latest revision. 

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

      Review the NodeInstallerProgressing status condition to verify that all nodes are at the latest revision. The output shows AllNodesAtLatestRevision upon successful update: 

      AllNodesAtLatestRevision
3 nodes are at revision 7 1
      1
      In this example, the latest revision number is 7.

      If the output includes multiple revision numbers, such as 2 nodes are at revision 6; 1 nodes are at revision 7, this means that the update is still in progress. Wait a few minutes and try again.

  13. Verify that all master hosts have started and joined the cluster.

    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 etcd

    Example output

    etcd-ip-10-0-143-125.ec2.internal                2/2     Running     0          9h
etcd-ip-10-0-154-194.ec2.internal                2/2     Running     0          9h
etcd-ip-10-0-173-171.ec2.internal                2/2     Running     0          9h

Note that it might take several minutes after completing this procedure for all services to be restored. For example, authentication by using oc login might not immediately work until the OAuth server pods are restarted.

5.4. Recovering from expired control plane certificates

5.4.1. Recovering from expired control plane certificates

As of OpenShift Container Platform 4.4.8, the cluster can automatically recover from expired control plane certificates. You no longer need to perform the manual steps that were required in previous versions.

The exception is that you must manually approve the pending node-bootstrapper certificate signing requests (CSRs) to recover kubelet certificates.

Use the following steps to approve the pending node-bootstrapper CSRs.

Procedure

  1. Get the list of current CSRs: 

    $ oc get csr

  2. Review the details of a CSR to verify that it is valid: 

    $ oc describe csr <csr_name> 1
    1
    <csr_name> is the name of a CSR from the list of current CSRs.

  3. Approve each valid node-bootstrapper CSR: 

    $ oc adm certificate approve <csr_name>

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