Chapter 8. High availability for hosted control planes

8.1. Recovering an unhealthy etcd cluster

In a highly available control plane, three etcd pods run as a part of a stateful set in an etcd cluster. To recover an etcd cluster, identify unhealthy etcd pods by checking the etcd cluster health.

8.1.1. Checking the status of an etcd cluster

You can check the status of the etcd cluster health by logging into any etcd pod.

Procedure

Print the health status of an etcd cluster by entering the following command:

sh-4.4# etcdctl endpoint status -w table

Example output

+------------------------------+-----------------+---------+---------+-----------+------------+-----------+------------+--------------------+--------+
|          ENDPOINT            |       ID        | VERSION | DB SIZE | IS LEADER | IS LEARNER | RAFT TERM | RAFT INDEX | RAFT APPLIED INDEX | ERRORS |
+------------------------------+-----------------+---------+---------+-----------+------------+-----------+------------+--------------------+--------+
| https://192.168.1xxx.20:2379 | 8fxxxxxxxxxx    |  3.5.12 |  123 MB |     false |      false |        10 |     180156 |             180156 |        |
| https://192.168.1xxx.21:2379 | a5xxxxxxxxxx    |  3.5.12 |  122 MB |     false |      false |        10 |     180156 |             180156 |        |
| https://192.168.1xxx.22:2379 | 7cxxxxxxxxxx    |  3.5.12 |  124 MB |      true |      false |        10 |     180156 |             180156 |        |
+-----------------------------+------------------+---------+---------+-----------+------------+-----------+------------+--------------------+--------+

8.1.2. Recovering a failing etcd pod

Each etcd pod of a 3-node cluster has its own persistent volume claim (PVC) to store its data. An etcd pod might fail because of corrupted or missing data. You can recover a failing etcd pod and its PVC.

Procedure

To confirm that the etcd pod is failing, enter the following command:

$ oc get pods -l app=etcd -n openshift-etcd

Example output

NAME     READY   STATUS             RESTARTS     AGE
etcd-0   2/2     Running            0            64m
etcd-1   2/2     Running            0            45m
etcd-2   1/2     CrashLoopBackOff   1 (5s ago)   64m

The failing etcd pod might have the CrashLoopBackOff or Error status.

Delete the failing pod and its PVC by entering the following command:
```
$ oc delete pods etcd-2 -n openshift-etcd
```

Verification

Verify that a new etcd pod is up and running by entering the following command:

$ oc get pods -l app=etcd -n openshift-etcd

Example output

NAME     READY   STATUS    RESTARTS   AGE
etcd-0   2/2     Running   0          67m
etcd-1   2/2     Running   0          48m
etcd-2   2/2     Running   0          2m2s

8.2. Backing up and restoring etcd in an on-premise environment

You can back up and restore etcd on a hosted cluster in an on-premise environment to fix failures.

8.2.1. Backing up and restoring etcd on a hosted cluster in an on-premise environment

By backing up and restoring etcd on a hosted cluster, you can fix failures, such as corrupted or missing data in an etcd member of a three node cluster. If multiple members of the etcd cluster encounter data loss or have a CrashLoopBackOff status, this approach helps prevent an etcd quorum loss.

Important

This procedure requires API downtime.

Prerequisites

The oc and jq binaries have been installed.

Procedure

First, set up your environment variables and scale down the API servers:

Set up environment variables for your hosted cluster by entering the following commands, replacing values as necessary:

$ CLUSTER_NAME=my-cluster

$ HOSTED_CLUSTER_NAMESPACE=clusters

$ CONTROL_PLANE_NAMESPACE="${HOSTED_CLUSTER_NAMESPACE}-${CLUSTER_NAME}"

Pause reconciliation of the hosted cluster by entering the following command, replacing values as necessary:

$ oc patch -n ${HOSTED_CLUSTER_NAMESPACE} hostedclusters/${CLUSTER_NAME} -p '{"spec":{"pausedUntil":"true"}}' --type=merge

Scale down the API servers by entering the following commands:

Scale down the kube-apiserver:

$ oc scale -n ${CONTROL_PLANE_NAMESPACE} deployment/kube-apiserver --replicas=0

Scale down the openshift-apiserver:

$ oc scale -n ${CONTROL_PLANE_NAMESPACE} deployment/openshift-apiserver --replicas=0

Scale down the openshift-oauth-apiserver:

$ oc scale -n ${CONTROL_PLANE_NAMESPACE} deployment/openshift-oauth-apiserver --replicas=0

Next, take a snapshot of etcd by using one of the following methods:
1. Use a previously backed-up snapshot of etcd.
2. If you have an available etcd pod, take a snapshot from the active etcd pod by completing the following steps:
  1. List etcd pods by entering the following command:
    $ oc get -n ${CONTROL_PLANE_NAMESPACE} pods -l app=etcd
  2. Take a snapshot of the pod database and save it locally to your machine by entering the following commands:
    $ ETCD_POD=etcd-0
    $ oc exec -n ${CONTROL_PLANE_NAMESPACE} -c etcd -t ${ETCD_POD} -- env ETCDCTL_API=3 /usr/bin/etcdctl \ --cacert /etc/etcd/tls/etcd-ca/ca.crt \ --cert /etc/etcd/tls/client/etcd-client.crt \ --key /etc/etcd/tls/client/etcd-client.key \ --endpoints=https://localhost:2379 \ snapshot save /var/lib/snapshot.db
  3. Verify that the snapshot is successful by entering the following command:
    $ oc exec -n ${CONTROL_PLANE_NAMESPACE} -c etcd -t ${ETCD_POD} -- env ETCDCTL_API=3 /usr/bin/etcdctl -w table snapshot status /var/lib/snapshot.db
3. Make a local copy of the snapshot by entering the following command:
```
$ oc cp -c etcd ${CONTROL_PLANE_NAMESPACE}/${ETCD_POD}:/var/lib/snapshot.db /tmp/etcd.snapshot.db
```
  1. Make a copy of the snapshot database from etcd persistent storage:
    List etcd pods by entering the following command:
    $ oc get -n ${CONTROL_PLANE_NAMESPACE} pods -l app=etcd
    Find a pod that is running and set its name as the value of ETCD_POD: ETCD_POD=etcd-0, and then copy its snapshot database by entering the following command:
    $ oc cp -c etcd ${CONTROL_PLANE_NAMESPACE}/${ETCD_POD}:/var/lib/data/member/snap/db /tmp/etcd.snapshot.db

Next, scale down the etcd statefulset by entering the following command:

$ oc scale -n ${CONTROL_PLANE_NAMESPACE} statefulset/etcd --replicas=0

Delete volumes for second and third members by entering the following command:
```
$ oc delete -n ${CONTROL_PLANE_NAMESPACE} pvc/data-etcd-1 pvc/data-etcd-2
```

Create a pod to access the first etcd member’s data:

Get the etcd image by entering the following command:

$ ETCD_IMAGE=$(oc get -n ${CONTROL_PLANE_NAMESPACE} statefulset/etcd -o jsonpath='{ .spec.template.spec.containers[0].image }')

Create a pod that allows access to etcd data:

$ cat << EOF | oc apply -n ${CONTROL_PLANE_NAMESPACE} -f -
apiVersion: apps/v1
kind: Deployment
metadata:
  name: etcd-data
spec:
  replicas: 1
  selector:
    matchLabels:
      app: etcd-data
  template:
    metadata:
      labels:
        app: etcd-data
    spec:
      containers:
      - name: access
        image: $ETCD_IMAGE
        volumeMounts:
        - name: data
          mountPath: /var/lib
        command:
        - /usr/bin/bash
        args:
        - -c
        - |-
          while true; do
            sleep 1000
          done
      volumes:
      - name: data
        persistentVolumeClaim:
          claimName: data-etcd-0
EOF

Check the status of the etcd-data pod and wait for it to be running by entering the following command:
```
$ oc get -n ${CONTROL_PLANE_NAMESPACE} pods -l app=etcd-data
```

Get the name of the etcd-data pod by entering the following command:

$ DATA_POD=$(oc get -n ${CONTROL_PLANE_NAMESPACE} pods --no-headers -l app=etcd-data -o name | cut -d/ -f2)

Copy an etcd snapshot into the pod by entering the following command:

$ oc cp /tmp/etcd.snapshot.db ${CONTROL_PLANE_NAMESPACE}/${DATA_POD}:/var/lib/restored.snap.db

Remove old data from the etcd-data pod by entering the following commands:

$ oc exec -n ${CONTROL_PLANE_NAMESPACE} ${DATA_POD} -- rm -rf /var/lib/data

$ oc exec -n ${CONTROL_PLANE_NAMESPACE} ${DATA_POD} -- mkdir -p /var/lib/data

Restore the etcd snapshot by entering the following command:

$ oc exec -n ${CONTROL_PLANE_NAMESPACE} ${DATA_POD} -- etcdutl snapshot restore /var/lib/restored.snap.db \
     --data-dir=/var/lib/data --skip-hash-check \
     --name etcd-0 \
     --initial-cluster-token=etcd-cluster \
     --initial-cluster etcd-0=https://etcd-0.etcd-discovery.${CONTROL_PLANE_NAMESPACE}.svc:2380,etcd-1=https://etcd-1.etcd-discovery.${CONTROL_PLANE_NAMESPACE}.svc:2380,etcd-2=https://etcd-2.etcd-discovery.${CONTROL_PLANE_NAMESPACE}.svc:2380 \
     --initial-advertise-peer-urls https://etcd-0.etcd-discovery.${CONTROL_PLANE_NAMESPACE}.svc:2380

Remove the temporary etcd snapshot from the pod by entering the following command:

$ oc exec -n ${CONTROL_PLANE_NAMESPACE} ${DATA_POD} -- rm /var/lib/restored.snap.db

Delete data access deployment by entering the following command:
```
$ oc delete -n ${CONTROL_PLANE_NAMESPACE} deployment/etcd-data
```

Scale up the etcd cluster by entering the following command:

$ oc scale -n ${CONTROL_PLANE_NAMESPACE} statefulset/etcd --replicas=3

Wait for the etcd member pods to return and report as available by entering the following command:
```
$ oc get -n ${CONTROL_PLANE_NAMESPACE} pods -l app=etcd -w
```

Scale up all etcd-writer deployments by entering the following command:

$ oc scale deployment -n ${CONTROL_PLANE_NAMESPACE} --replicas=3 kube-apiserver openshift-apiserver openshift-oauth-apiserver

Restore reconciliation of the hosted cluster by entering the following command:

$ oc patch -n ${CLUSTER_NAMESPACE} hostedclusters/${CLUSTER_NAME} -p '{"spec":{"pausedUntil":""}}' --type=merge

8.3. Backing up and restoring etcd on AWS

You can back up and restore etcd on a hosted cluster on Amazon Web Services (AWS) to fix failures.

Important

Hosted control planes on the AWS platform is a Technology Preview feature only. Technology Preview features are not supported with Red Hat production service level agreements (SLAs) and might not be functionally complete. Red Hat does not recommend using them in production. These features provide early access to upcoming product features, enabling customers to test functionality and provide feedback during the development process.

For more information about the support scope of Red Hat Technology Preview features, see Technology Preview Features Support Scope.

8.3.1. Taking a snapshot of etcd for a hosted cluster

To back up etcd for a hosted cluster, you must take a snapshot of etcd. Later, you can restore etcd by using the snapshot.

Important

This procedure requires API downtime.

Procedure

Pause reconciliation of the hosted cluster by entering the following command:

$ oc patch -n clusters hostedclusters/<hosted_cluster_name> -p '{"spec":{"pausedUntil":"true"}}' --type=merge

Stop all etcd-writer deployments by entering the following command:

$ oc scale deployment -n <hosted_cluster_namespace> --replicas=0 kube-apiserver openshift-apiserver openshift-oauth-apiserver

To take an etcd snapshot, use the exec command in each etcd container by entering the following command:

$ oc exec -it <etcd_pod_name> -n <hosted_cluster_namespace> -- env ETCDCTL_API=3 /usr/bin/etcdctl --cacert /etc/etcd/tls/etcd-ca/ca.crt --cert /etc/etcd/tls/client/etcd-client.crt --key /etc/etcd/tls/client/etcd-client.key --endpoints=localhost:2379 snapshot save /var/lib/data/snapshot.db

To check the snapshot status, use the exec command in each etcd container by running the following command:

$ oc exec -it <etcd_pod_name> -n <hosted_cluster_namespace> -- env ETCDCTL_API=3 /usr/bin/etcdctl -w table snapshot status /var/lib/data/snapshot.db

Copy the snapshot data to a location where you can retrieve it later, such as an S3 bucket. See the following example.

Note

The following example uses signature version 2. If you are in a region that supports signature version 4, such as the us-east-2 region, use signature version 4. Otherwise, when copying the snapshot to an S3 bucket, the upload fails.

Example

BUCKET_NAME=somebucket
FILEPATH="/${BUCKET_NAME}/${CLUSTER_NAME}-snapshot.db"
CONTENT_TYPE="application/x-compressed-tar"
DATE_VALUE=`date -R`
SIGNATURE_STRING="PUT\n\n${CONTENT_TYPE}\n${DATE_VALUE}\n${FILEPATH}"
ACCESS_KEY=accesskey
SECRET_KEY=secret
SIGNATURE_HASH=`echo -en ${SIGNATURE_STRING} | openssl sha1 -hmac ${SECRET_KEY} -binary | base64`

oc exec -it etcd-0 -n ${HOSTED_CLUSTER_NAMESPACE} -- curl -X PUT -T "/var/lib/data/snapshot.db" \
  -H "Host: ${BUCKET_NAME}.s3.amazonaws.com" \
  -H "Date: ${DATE_VALUE}" \
  -H "Content-Type: ${CONTENT_TYPE}" \
  -H "Authorization: AWS ${ACCESS_KEY}:${SIGNATURE_HASH}" \
  https://${BUCKET_NAME}.s3.amazonaws.com/${CLUSTER_NAME}-snapshot.db

To restore the snapshot on a new cluster later, save the encryption secret that the hosted cluster references.
1. Get the secret encryption key by entering the following command:
```
$ oc get hostedcluster <hosted_cluster_name> -o=jsonpath='{.spec.secretEncryption.aescbc}'
{"activeKey":{"name":"<hosted_cluster_name>-etcd-encryption-key"}}
```
2. Save the secret encryption key by entering the following command:
```
$ oc get secret <hosted_cluster_name>-etcd-encryption-key -o=jsonpath='{.data.key}'
```
  You can decrypt this key when restoring a snapshot on a new cluster.

Next steps

Restore the etcd snapshot.

8.3.2. Restoring an etcd snapshot on a hosted cluster

If you have a snapshot of etcd from your hosted cluster, you can restore it. Currently, you can restore an etcd snapshot only during cluster creation.

To restore an etcd snapshot, you modify the output from the create cluster --render command and define a restoreSnapshotURL value in the etcd section of the HostedCluster specification.

Note

The --render flag in the hcp create command does not render the secrets. To render the secrets, you must use both the --render and the --render-sensitive flags in the hcp create command.

Prerequisites

You took an etcd snapshot on a hosted cluster.

Procedure

On the aws command-line interface (CLI), create a pre-signed URL so that you can download your etcd snapshot from S3 without passing credentials to the etcd deployment:
```
ETCD_SNAPSHOT=${ETCD_SNAPSHOT:-"s3://${BUCKET_NAME}/${CLUSTER_NAME}-snapshot.db"}
ETCD_SNAPSHOT_URL=$(aws s3 presign ${ETCD_SNAPSHOT})
```

Modify the HostedCluster specification to refer to the URL:

spec:
  etcd:
    managed:
      storage:
        persistentVolume:
          size: 4Gi
        type: PersistentVolume
        restoreSnapshotURL:
        - "${ETCD_SNAPSHOT_URL}"
    managementType: Managed

Ensure that the secret that you referenced from the spec.secretEncryption.aescbc value contains the same AES key that you saved in the previous steps.

8.4. Disaster recovery for a hosted cluster in AWS

You can recover a hosted cluster to the same region within Amazon Web Services (AWS). For example, you need disaster recovery when the upgrade of a management cluster fails and the hosted cluster is in a read-only state.

Important

Hosted control planes is a Technology Preview feature only. Technology Preview features are not supported with Red Hat production service level agreements (SLAs) and might not be functionally complete. Red Hat does not recommend using them in production. These features provide early access to upcoming product features, enabling customers to test functionality and provide feedback during the development process.

For more information about the support scope of Red Hat Technology Preview features, see Technology Preview Features Support Scope.

The disaster recovery process involves the following steps:

Backing up the hosted cluster on the source management cluster
Restoring the hosted cluster on a destination management cluster
Deleting the hosted cluster from the source management cluster

Your workloads remain running during the process. The Cluster API might be unavailable for a period, but that does not affect the services that are running on the worker nodes.

Important

Both the source management cluster and the destination management cluster must have the --external-dns flags to maintain the API server URL. That way, the server URL ends with https://api-sample-hosted.sample-hosted.aws.openshift.com. See the following example:

Example: External DNS flags

--external-dns-provider=aws \
--external-dns-credentials=<path_to_aws_credentials_file> \
--external-dns-domain-filter=<basedomain>

If you do not include the --external-dns flags to maintain the API server URL, you cannot migrate the hosted cluster.

8.4.1. Overview of the backup and restore process

The backup and restore process works as follows:

On management cluster 1, which you can think of as the source management cluster, the control plane and workers interact by using the external DNS API. The external DNS API is accessible, and a load balancer sits between the management clusters.
You take a snapshot of the hosted cluster, which includes etcd, the control plane, and the worker nodes. During this process, the worker nodes continue to try to access the external DNS API even if it is not accessible, the workloads are running, the control plane is saved in a local manifest file, and etcd is backed up to an S3 bucket. The data plane is active and the control plane is paused.
On management cluster 2, which you can think of as the destination management cluster, you restore etcd from the S3 bucket and restore the control plane from the local manifest file. During this process, the external DNS API is stopped, the hosted cluster API becomes inaccessible, and any workers that use the API are unable to update their manifest files, but the workloads are still running.
The external DNS API is accessible again, and the worker nodes use it to move to management cluster 2. The external DNS API can access the load balancer that points to the control plane.
On management cluster 2, the control plane and worker nodes interact by using the external DNS API. The resources are deleted from management cluster 1, except for the S3 backup of etcd. If you try to set up the hosted cluster again on mangagement cluster 1, it will not work.

8.4.2. Backing up a hosted cluster

To recover your hosted cluster in your target management cluster, you first need to back up all of the relevant data.

Procedure

Create a configmap file to declare the source management cluster by entering this command:

$ oc create configmap mgmt-parent-cluster -n default --from-literal=from=${MGMT_CLUSTER_NAME}

Shut down the reconciliation in the hosted cluster and in the node pools by entering these commands:

$ PAUSED_UNTIL="true"
$ oc patch -n ${HC_CLUSTER_NS} hostedclusters/${HC_CLUSTER_NAME} -p '{"spec":{"pausedUntil":"'${PAUSED_UNTIL}'"}}' --type=merge
$ oc scale deployment -n ${HC_CLUSTER_NS}-${HC_CLUSTER_NAME} --replicas=0 kube-apiserver openshift-apiserver openshift-oauth-apiserver control-plane-operator

$ PAUSED_UNTIL="true"
$ oc patch -n ${HC_CLUSTER_NS} hostedclusters/${HC_CLUSTER_NAME} -p '{"spec":{"pausedUntil":"'${PAUSED_UNTIL}'"}}' --type=merge
$ oc patch -n ${HC_CLUSTER_NS} nodepools/${NODEPOOLS} -p '{"spec":{"pausedUntil":"'${PAUSED_UNTIL}'"}}' --type=merge
$ oc scale deployment -n ${HC_CLUSTER_NS}-${HC_CLUSTER_NAME} --replicas=0 kube-apiserver openshift-apiserver openshift-oauth-apiserver control-plane-operator

Back up etcd and upload the data to an S3 bucket by running this bash script:

Tip

Wrap this script in a function and call it from the main function.

# ETCD Backup
ETCD_PODS="etcd-0"
if [ "${CONTROL_PLANE_AVAILABILITY_POLICY}" = "HighlyAvailable" ]; then
  ETCD_PODS="etcd-0 etcd-1 etcd-2"
fi

for POD in ${ETCD_PODS}; do
  # Create an etcd snapshot
  oc exec -it ${POD} -n ${HC_CLUSTER_NS}-${HC_CLUSTER_NAME} -- env ETCDCTL_API=3 /usr/bin/etcdctl --cacert /etc/etcd/tls/client/etcd-client-ca.crt --cert /etc/etcd/tls/client/etcd-client.crt --key /etc/etcd/tls/client/etcd-client.key --endpoints=localhost:2379 snapshot save /var/lib/data/snapshot.db
  oc exec -it ${POD} -n ${HC_CLUSTER_NS}-${HC_CLUSTER_NAME} -- env ETCDCTL_API=3 /usr/bin/etcdctl -w table snapshot status /var/lib/data/snapshot.db

  FILEPATH="/${BUCKET_NAME}/${HC_CLUSTER_NAME}-${POD}-snapshot.db"
  CONTENT_TYPE="application/x-compressed-tar"
  DATE_VALUE=`date -R`
  SIGNATURE_STRING="PUT\n\n${CONTENT_TYPE}\n${DATE_VALUE}\n${FILEPATH}"

  set +x
  ACCESS_KEY=$(grep aws_access_key_id ${AWS_CREDS} | head -n1 | cut -d= -f2 | sed "s/ //g")
  SECRET_KEY=$(grep aws_secret_access_key ${AWS_CREDS} | head -n1 | cut -d= -f2 | sed "s/ //g")
  SIGNATURE_HASH=$(echo -en ${SIGNATURE_STRING} | openssl sha1 -hmac "${SECRET_KEY}" -binary | base64)
  set -x

  # FIXME: this is pushing to the OIDC bucket
  oc exec -it etcd-0 -n ${HC_CLUSTER_NS}-${HC_CLUSTER_NAME} -- curl -X PUT -T "/var/lib/data/snapshot.db" \
    -H "Host: ${BUCKET_NAME}.s3.amazonaws.com" \
    -H "Date: ${DATE_VALUE}" \
    -H "Content-Type: ${CONTENT_TYPE}" \
    -H "Authorization: AWS ${ACCESS_KEY}:${SIGNATURE_HASH}" \
    https://${BUCKET_NAME}.s3.amazonaws.com/${HC_CLUSTER_NAME}-${POD}-snapshot.db
done

For more information about backing up etcd, see "Backing up and restoring etcd on a hosted cluster".

Back up Kubernetes and OpenShift Container Platform objects by entering the following commands. You need to back up the following objects:

HostedCluster and NodePool objects from the HostedCluster namespace
HostedCluster secrets from the HostedCluster namespace
HostedControlPlane from the Hosted Control Plane namespace
Cluster from the Hosted Control Plane namespace
AWSCluster, AWSMachineTemplate, and AWSMachine from the Hosted Control Plane namespace
MachineDeployments, MachineSets, and Machines from the Hosted Control Plane namespace

ControlPlane secrets from the Hosted Control Plane namespace

$ mkdir -p ${BACKUP_DIR}/namespaces/${HC_CLUSTER_NS} ${BACKUP_DIR}/namespaces/${HC_CLUSTER_NS}-${HC_CLUSTER_NAME}
$ chmod 700 ${BACKUP_DIR}/namespaces/

# HostedCluster
$ echo "Backing Up HostedCluster Objects:"
$ oc get hc ${HC_CLUSTER_NAME} -n ${HC_CLUSTER_NS} -o yaml > ${BACKUP_DIR}/namespaces/${HC_CLUSTER_NS}/hc-${HC_CLUSTER_NAME}.yaml
$ echo "--> HostedCluster"
$ sed -i '' -e '/^status:$/,$d' ${BACKUP_DIR}/namespaces/${HC_CLUSTER_NS}/hc-${HC_CLUSTER_NAME}.yaml

# NodePool
$ oc get np ${NODEPOOLS} -n ${HC_CLUSTER_NS} -o yaml > ${BACKUP_DIR}/namespaces/${HC_CLUSTER_NS}/np-${NODEPOOLS}.yaml
$ echo "--> NodePool"
$ sed -i '' -e '/^status:$/,$ d' ${BACKUP_DIR}/namespaces/${HC_CLUSTER_NS}/np-${NODEPOOLS}.yaml

# Secrets in the HC Namespace
$ echo "--> HostedCluster Secrets:"
for s in $(oc get secret -n ${HC_CLUSTER_NS} | grep "^${HC_CLUSTER_NAME}" | awk '{print $1}'); do
    oc get secret -n ${HC_CLUSTER_NS} $s -o yaml > ${BACKUP_DIR}/namespaces/${HC_CLUSTER_NS}/secret-${s}.yaml
done

# Secrets in the HC Control Plane Namespace
$ echo "--> HostedCluster ControlPlane Secrets:"
for s in $(oc get secret -n ${HC_CLUSTER_NS}-${HC_CLUSTER_NAME} | egrep -v "docker|service-account-token|oauth-openshift|NAME|token-${HC_CLUSTER_NAME}" | awk '{print $1}'); do
    oc get secret -n ${HC_CLUSTER_NS}-${HC_CLUSTER_NAME} $s -o yaml > ${BACKUP_DIR}/namespaces/${HC_CLUSTER_NS}-${HC_CLUSTER_NAME}/secret-${s}.yaml
done

# Hosted Control Plane
$ echo "--> HostedControlPlane:"
$ oc get hcp ${HC_CLUSTER_NAME} -n ${HC_CLUSTER_NS}-${HC_CLUSTER_NAME} -o yaml > ${BACKUP_DIR}/namespaces/${HC_CLUSTER_NS}-${HC_CLUSTER_NAME}/hcp-${HC_CLUSTER_NAME}.yaml

# Cluster
$ echo "--> Cluster:"
$ CL_NAME=$(oc get hcp ${HC_CLUSTER_NAME} -n ${HC_CLUSTER_NS}-${HC_CLUSTER_NAME} -o jsonpath={.metadata.labels.\*} | grep ${HC_CLUSTER_NAME})
$ oc get cluster ${CL_NAME} -n ${HC_CLUSTER_NS}-${HC_CLUSTER_NAME} -o yaml > ${BACKUP_DIR}/namespaces/${HC_CLUSTER_NS}-${HC_CLUSTER_NAME}/cl-${HC_CLUSTER_NAME}.yaml

# AWS Cluster
$ echo "--> AWS Cluster:"
$ oc get awscluster ${HC_CLUSTER_NAME} -n ${HC_CLUSTER_NS}-${HC_CLUSTER_NAME} -o yaml > ${BACKUP_DIR}/namespaces/${HC_CLUSTER_NS}-${HC_CLUSTER_NAME}/awscl-${HC_CLUSTER_NAME}.yaml

# AWS MachineTemplate
$ echo "--> AWS Machine Template:"
$ oc get awsmachinetemplate ${NODEPOOLS} -n ${HC_CLUSTER_NS}-${HC_CLUSTER_NAME} -o yaml > ${BACKUP_DIR}/namespaces/${HC_CLUSTER_NS}-${HC_CLUSTER_NAME}/awsmt-${HC_CLUSTER_NAME}.yaml

# AWS Machines
$ echo "--> AWS Machine:"
$ CL_NAME=$(oc get hcp ${HC_CLUSTER_NAME} -n ${HC_CLUSTER_NS}-${HC_CLUSTER_NAME} -o jsonpath={.metadata.labels.\*} | grep ${HC_CLUSTER_NAME})
for s in $(oc get awsmachines -n ${HC_CLUSTER_NS}-${HC_CLUSTER_NAME} --no-headers | grep ${CL_NAME} | cut -f1 -d\ ); do
    oc get -n ${HC_CLUSTER_NS}-${HC_CLUSTER_NAME} awsmachines $s -o yaml > ${BACKUP_DIR}/namespaces/${HC_CLUSTER_NS}-${HC_CLUSTER_NAME}/awsm-${s}.yaml
done

# MachineDeployments
$ echo "--> HostedCluster MachineDeployments:"
for s in $(oc get machinedeployment -n ${HC_CLUSTER_NS}-${HC_CLUSTER_NAME} -o name); do
    mdp_name=$(echo ${s} | cut -f 2 -d /)
    oc get -n ${HC_CLUSTER_NS}-${HC_CLUSTER_NAME} $s -o yaml > ${BACKUP_DIR}/namespaces/${HC_CLUSTER_NS}-${HC_CLUSTER_NAME}/machinedeployment-${mdp_name}.yaml
done

# MachineSets
$ echo "--> HostedCluster MachineSets:"
for s in $(oc get machineset -n ${HC_CLUSTER_NS}-${HC_CLUSTER_NAME} -o name); do
    ms_name=$(echo ${s} | cut -f 2 -d /)
    oc get -n ${HC_CLUSTER_NS}-${HC_CLUSTER_NAME} $s -o yaml > ${BACKUP_DIR}/namespaces/${HC_CLUSTER_NS}-${HC_CLUSTER_NAME}/machineset-${ms_name}.yaml
done

# Machines
$ echo "--> HostedCluster Machine:"
for s in $(oc get machine -n ${HC_CLUSTER_NS}-${HC_CLUSTER_NAME} -o name); do
    m_name=$(echo ${s} | cut -f 2 -d /)
    oc get -n ${HC_CLUSTER_NS}-${HC_CLUSTER_NAME} $s -o yaml > ${BACKUP_DIR}/namespaces/${HC_CLUSTER_NS}-${HC_CLUSTER_NAME}/machine-${m_name}.yaml
done

Clean up the ControlPlane routes by entering this command:
```
$ oc delete routes -n ${HC_CLUSTER_NS}-${HC_CLUSTER_NAME} --all
```
By entering that command, you enable the ExternalDNS Operator to delete the Route53 entries.

Verify that the Route53 entries are clean by running this script:

function clean_routes() {

    if [[ -z "${1}" ]];then
        echo "Give me the NS where to clean the routes"
        exit 1
    fi

    # Constants
    if [[ -z "${2}" ]];then
        echo "Give me the Route53 zone ID"
        exit 1
    fi

    ZONE_ID=${2}
    ROUTES=10
    timeout=40
    count=0

    # This allows us to remove the ownership in the AWS for the API route
    oc delete route -n ${1} --all

    while [ ${ROUTES} -gt 2 ]
    do
        echo "Waiting for ExternalDNS Operator to clean the DNS Records in AWS Route53 where the zone id is: ${ZONE_ID}..."
        echo "Try: (${count}/${timeout})"
        sleep 10
        if [[ $count -eq timeout ]];then
            echo "Timeout waiting for cleaning the Route53 DNS records"
            exit 1
        fi
        count=$((count+1))
        ROUTES=$(aws route53 list-resource-record-sets --hosted-zone-id ${ZONE_ID} --max-items 10000 --output json | grep -c ${EXTERNAL_DNS_DOMAIN})
    done
}

# SAMPLE: clean_routes "<HC ControlPlane Namespace>" "<AWS_ZONE_ID>"
clean_routes "${HC_CLUSTER_NS}-${HC_CLUSTER_NAME}" "${AWS_ZONE_ID}"

Verification

Check all of the OpenShift Container Platform objects and the S3 bucket to verify that everything looks as expected.

Next steps

Restore your hosted cluster.

8.4.3. Restoring a hosted cluster

Gather all of the objects that you backed up and restore them in your destination management cluster.

Prerequisites

You backed up the data from your source management cluster.

Tip

Ensure that the kubeconfig file of the destination management cluster is placed as it is set in the KUBECONFIG variable or, if you use the script, in the MGMT2_KUBECONFIG variable. Use export KUBECONFIG=<Kubeconfig FilePath> or, if you use the script, use export KUBECONFIG=${MGMT2_KUBECONFIG}.

Procedure

Verify that the new management cluster does not contain any namespaces from the cluster that you are restoring by entering these commands:

# Just in case
$ export KUBECONFIG=${MGMT2_KUBECONFIG}
$ BACKUP_DIR=${HC_CLUSTER_DIR}/backup

# Namespace deletion in the destination Management cluster
$ oc delete ns ${HC_CLUSTER_NS} || true
$ oc delete ns ${HC_CLUSTER_NS}-{HC_CLUSTER_NAME} || true

Re-create the deleted namespaces by entering these commands:

# Namespace creation
$ oc new-project ${HC_CLUSTER_NS}
$ oc new-project ${HC_CLUSTER_NS}-${HC_CLUSTER_NAME}

Restore the secrets in the HC namespace by entering this command:
```
$ oc apply -f ${BACKUP_DIR}/namespaces/${HC_CLUSTER_NS}/secret-*
```

Restore the objects in the HostedCluster control plane namespace by entering these commands:

# Secrets
$ oc apply -f ${BACKUP_DIR}/namespaces/${HC_CLUSTER_NS}-${HC_CLUSTER_NAME}/secret-*

# Cluster
$ oc apply -f ${BACKUP_DIR}/namespaces/${HC_CLUSTER_NS}-${HC_CLUSTER_NAME}/hcp-*
$ oc apply -f ${BACKUP_DIR}/namespaces/${HC_CLUSTER_NS}-${HC_CLUSTER_NAME}/cl-*

If you are recovering the nodes and the node pool to reuse AWS instances, restore the objects in the HC control plane namespace by entering these commands:

# AWS
$ oc apply -f ${BACKUP_DIR}/namespaces/${HC_CLUSTER_NS}-${HC_CLUSTER_NAME}/awscl-*
$ oc apply -f ${BACKUP_DIR}/namespaces/${HC_CLUSTER_NS}-${HC_CLUSTER_NAME}/awsmt-*
$ oc apply -f ${BACKUP_DIR}/namespaces/${HC_CLUSTER_NS}-${HC_CLUSTER_NAME}/awsm-*

# Machines
$ oc apply -f ${BACKUP_DIR}/namespaces/${HC_CLUSTER_NS}-${HC_CLUSTER_NAME}/machinedeployment-*
$ oc apply -f ${BACKUP_DIR}/namespaces/${HC_CLUSTER_NS}-${HC_CLUSTER_NAME}/machineset-*
$ oc apply -f ${BACKUP_DIR}/namespaces/${HC_CLUSTER_NS}-${HC_CLUSTER_NAME}/machine-*

Restore the etcd data and the hosted cluster by running this bash script:

ETCD_PODS="etcd-0"
if [ "${CONTROL_PLANE_AVAILABILITY_POLICY}" = "HighlyAvailable" ]; then
  ETCD_PODS="etcd-0 etcd-1 etcd-2"
fi

HC_RESTORE_FILE=${BACKUP_DIR}/namespaces/${HC_CLUSTER_NS}/hc-${HC_CLUSTER_NAME}-restore.yaml
HC_BACKUP_FILE=${BACKUP_DIR}/namespaces/${HC_CLUSTER_NS}/hc-${HC_CLUSTER_NAME}.yaml
HC_NEW_FILE=${BACKUP_DIR}/namespaces/${HC_CLUSTER_NS}/hc-${HC_CLUSTER_NAME}-new.yaml
cat ${HC_BACKUP_FILE} > ${HC_NEW_FILE}
cat > ${HC_RESTORE_FILE} <<EOF
    restoreSnapshotURL:
EOF

for POD in ${ETCD_PODS}; do
  # Create a pre-signed URL for the etcd snapshot
  ETCD_SNAPSHOT="s3://${BUCKET_NAME}/${HC_CLUSTER_NAME}-${POD}-snapshot.db"
  ETCD_SNAPSHOT_URL=$(AWS_DEFAULT_REGION=${MGMT2_REGION} aws s3 presign ${ETCD_SNAPSHOT})

  # FIXME no CLI support for restoreSnapshotURL yet
  cat >> ${HC_RESTORE_FILE} <<EOF
    - "${ETCD_SNAPSHOT_URL}"
EOF
done

cat ${HC_RESTORE_FILE}

if ! grep ${HC_CLUSTER_NAME}-snapshot.db ${HC_NEW_FILE}; then
  sed -i '' -e "/type: PersistentVolume/r ${HC_RESTORE_FILE}" ${HC_NEW_FILE}
  sed -i '' -e '/pausedUntil:/d' ${HC_NEW_FILE}
fi

HC=$(oc get hc -n ${HC_CLUSTER_NS} ${HC_CLUSTER_NAME} -o name || true)
if [[ ${HC} == "" ]];then
    echo "Deploying HC Cluster: ${HC_CLUSTER_NAME} in ${HC_CLUSTER_NS} namespace"
    oc apply -f ${HC_NEW_FILE}
else
    echo "HC Cluster ${HC_CLUSTER_NAME} already exists, avoiding step"
fi

If you are recovering the nodes and the node pool to reuse AWS instances, restore the node pool by entering this command:
```
$ oc apply -f ${BACKUP_DIR}/namespaces/${HC_CLUSTER_NS}/np-*
```

Verification

To verify that the nodes are fully restored, use this function:

timeout=40
count=0
NODE_STATUS=$(oc get nodes --kubeconfig=${HC_KUBECONFIG} | grep -v NotReady | grep -c "worker") || NODE_STATUS=0

while [ ${NODE_POOL_REPLICAS} != ${NODE_STATUS} ]
do
    echo "Waiting for Nodes to be Ready in the destination MGMT Cluster: ${MGMT2_CLUSTER_NAME}"
    echo "Try: (${count}/${timeout})"
    sleep 30
    if [[ $count -eq timeout ]];then
        echo "Timeout waiting for Nodes in the destination MGMT Cluster"
        exit 1
    fi
    count=$((count+1))
    NODE_STATUS=$(oc get nodes --kubeconfig=${HC_KUBECONFIG} | grep -v NotReady | grep -c "worker") || NODE_STATUS=0
done

Next steps

Shut down and delete your cluster.

8.4.4. Deleting a hosted cluster from your source management cluster

After you back up your hosted cluster and restore it to your destination management cluster, you shut down and delete the hosted cluster on your source management cluster.

Prerequisites

You backed up your data and restored it to your source management cluster.

Tip

Ensure that the kubeconfig file of the destination management cluster is placed as it is set in the KUBECONFIG variable or, if you use the script, in the MGMT_KUBECONFIG variable. Use export KUBECONFIG=<Kubeconfig FilePath> or, if you use the script, use export KUBECONFIG=${MGMT_KUBECONFIG}.

Procedure

Scale the deployment and statefulset objects by entering these commands:
Important
Do not scale the stateful set if the value of its spec.persistentVolumeClaimRetentionPolicy.whenScaled field is set to Delete, because this could lead to a loss of data.
As a workaround, update the value of the spec.persistentVolumeClaimRetentionPolicy.whenScaled field to Retain. Ensure that no controllers exist that reconcile the stateful set and would return the value back to Delete, which could lead to a loss of data.
```
# Just in case
$ export KUBECONFIG=${MGMT_KUBECONFIG}

# Scale down deployments
$ oc scale deployment -n ${HC_CLUSTER_NS}-${HC_CLUSTER_NAME} --replicas=0 --all
$ oc scale statefulset.apps -n ${HC_CLUSTER_NS}-${HC_CLUSTER_NAME} --replicas=0 --all
$ sleep 15
```

Delete the NodePool objects by entering these commands:

NODEPOOLS=$(oc get nodepools -n ${HC_CLUSTER_NS} -o=jsonpath='{.items[?(@.spec.clusterName=="'${HC_CLUSTER_NAME}'")].metadata.name}')
if [[ ! -z "${NODEPOOLS}" ]];then
    oc patch -n "${HC_CLUSTER_NS}" nodepool ${NODEPOOLS} --type=json --patch='[ { "op":"remove", "path": "/metadata/finalizers" }]'
    oc delete np -n ${HC_CLUSTER_NS} ${NODEPOOLS}
fi

Delete the machine and machineset objects by entering these commands:

# Machines
for m in $(oc get machines -n ${HC_CLUSTER_NS}-${HC_CLUSTER_NAME} -o name); do
    oc patch -n ${HC_CLUSTER_NS}-${HC_CLUSTER_NAME} ${m} --type=json --patch='[ { "op":"remove", "path": "/metadata/finalizers" }]' || true
    oc delete -n ${HC_CLUSTER_NS}-${HC_CLUSTER_NAME} ${m} || true
done

$ oc delete machineset -n ${HC_CLUSTER_NS}-${HC_CLUSTER_NAME} --all || true

Delete the cluster object by entering these commands:

# Cluster
$ C_NAME=$(oc get cluster -n ${HC_CLUSTER_NS}-${HC_CLUSTER_NAME} -o name)
$ oc patch -n ${HC_CLUSTER_NS}-${HC_CLUSTER_NAME} ${C_NAME} --type=json --patch='[ { "op":"remove", "path": "/metadata/finalizers" }]'
$ oc delete cluster.cluster.x-k8s.io -n ${HC_CLUSTER_NS}-${HC_CLUSTER_NAME} --all

Delete the AWS machines (Kubernetes objects) by entering these commands. Do not worry about deleting the real AWS machines. The cloud instances will not be affected.

# AWS Machines
for m in $(oc get awsmachine.infrastructure.cluster.x-k8s.io -n ${HC_CLUSTER_NS}-${HC_CLUSTER_NAME} -o name)
do
    oc patch -n ${HC_CLUSTER_NS}-${HC_CLUSTER_NAME} ${m} --type=json --patch='[ { "op":"remove", "path": "/metadata/finalizers" }]' || true
    oc delete -n ${HC_CLUSTER_NS}-${HC_CLUSTER_NAME} ${m} || true
done

Delete the HostedControlPlane and ControlPlane HC namespace objects by entering these commands:

# Delete HCP and ControlPlane HC NS
$ oc patch -n ${HC_CLUSTER_NS}-${HC_CLUSTER_NAME} hostedcontrolplane.hypershift.openshift.io ${HC_CLUSTER_NAME} --type=json --patch='[ { "op":"remove", "path": "/metadata/finalizers" }]'
$ oc delete hostedcontrolplane.hypershift.openshift.io -n ${HC_CLUSTER_NS}-${HC_CLUSTER_NAME} --all
$ oc delete ns ${HC_CLUSTER_NS}-${HC_CLUSTER_NAME} || true

Delete the HostedCluster and HC namespace objects by entering these commands:

# Delete HC and HC Namespace
$ oc -n ${HC_CLUSTER_NS} patch hostedclusters ${HC_CLUSTER_NAME} -p '{"metadata":{"finalizers":null}}' --type merge || true
$ oc delete hc -n ${HC_CLUSTER_NS} ${HC_CLUSTER_NAME}  || true
$ oc delete ns ${HC_CLUSTER_NS} || true

Verification

To verify that everything works, enter these commands:

# Validations
$ export KUBECONFIG=${MGMT2_KUBECONFIG}

$ oc get hc -n ${HC_CLUSTER_NS}
$ oc get np -n ${HC_CLUSTER_NS}
$ oc get pod -n ${HC_CLUSTER_NS}-${HC_CLUSTER_NAME}
$ oc get machines -n ${HC_CLUSTER_NS}-${HC_CLUSTER_NAME}

# Inside the HostedCluster
$ export KUBECONFIG=${HC_KUBECONFIG}
$ oc get clusterversion
$ oc get nodes

Next steps

Delete the OVN pods in the hosted cluster so that you can connect to the new OVN control plane that runs in the new management cluster:

Load the KUBECONFIG environment variable with the hosted cluster’s kubeconfig path.

Enter this command:

$ oc delete pod -n openshift-ovn-kubernetes --all

Chapter 8. High availability for hosted control planes

8.1. Recovering an unhealthy etcd cluster

8.1.1. Checking the status of an etcd cluster

8.1.2. Recovering a failing etcd pod

8.2. Backing up and restoring etcd in an on-premise environment

8.2.1. Backing up and restoring etcd on a hosted cluster in an on-premise environment

8.3. Backing up and restoring etcd on AWS

8.3.1. Taking a snapshot of etcd for a hosted cluster

8.3.2. Restoring an etcd snapshot on a hosted cluster

8.4. Disaster recovery for a hosted cluster in AWS

8.4.1. Overview of the backup and restore process

8.4.2. Backing up a hosted cluster

8.4.3. Restoring a hosted cluster

8.4.4. Deleting a hosted cluster from your source management cluster

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