Steps to Restore from cStor Backup to Replicated Storage for Replicated DBs (Mongo)

info

Before you begin, make sure you have the following:

• Access to a Kubernetes cluster with Velero installed.
• A backup of your Mongo database created using Velero.
• Replicated Storage (a.k.a Replicated Engine or Mayastor) configured in your Kubernetes environment.

Step 1: Install Velero with GCP Provider on Destination (Replicated Storage Cluster)

Install Velero with the GCP provider, ensuring you use the same values for the BUCKET-NAME and SECRET-FILENAME placeholders that you used originally. These placeholders should be replaced with your specific values:

Command

velero install --use-node-agent --provider gcp --plugins velero/velero-plugin-for-gcp:v1.6.0 --bucket BUCKET-NAME --secret-file SECRET-FILENAME --uploader-type restic

Output

CustomResourceDefinition/backuprepositories.velero.io: attempting to create resource

CustomResourceDefinition/backuprepositories.velero.io: attempting to create resource client

CustomResourceDefinition/backuprepositories.velero.io: created

CustomResourceDefinition/backups.velero.io: attempting to create resource

CustomResourceDefinition/backups.velero.io: attempting to create resource client

CustomResourceDefinition/backups.velero.io: created

CustomResourceDefinition/backupstoragelocations.velero.io: attempting to create resource

CustomResourceDefinition/backupstoragelocations.velero.io: attempting to create resource client

CustomResourceDefinition/backupstoragelocations.velero.io: created

CustomResourceDefinition/deletebackuprequests.velero.io: attempting to create resource

CustomResourceDefinition/deletebackuprequests.velero.io: attempting to create resource client

CustomResourceDefinition/deletebackuprequests.velero.io: created

CustomResourceDefinition/downloadrequests.velero.io: attempting to create resource

CustomResourceDefinition/downloadrequests.velero.io: attempting to create resource client

CustomResourceDefinition/downloadrequests.velero.io: created

CustomResourceDefinition/podvolumebackups.velero.io: attempting to create resource

CustomResourceDefinition/podvolumebackups.velero.io: attempting to create resource client

CustomResourceDefinition/podvolumebackups.velero.io: created

CustomResourceDefinition/podvolumerestores.velero.io: attempting to create resource

CustomResourceDefinition/podvolumerestores.velero.io: attempting to create resource client

CustomResourceDefinition/podvolumerestores.velero.io: created

CustomResourceDefinition/restores.velero.io: attempting to create resource

CustomResourceDefinition/restores.velero.io: attempting to create resource client

CustomResourceDefinition/restores.velero.io: created

CustomResourceDefinition/schedules.velero.io: attempting to create resource

CustomResourceDefinition/schedules.velero.io: attempting to create resource client

CustomResourceDefinition/schedules.velero.io: created

CustomResourceDefinition/serverstatusrequests.velero.io: attempting to create resource

CustomResourceDefinition/serverstatusrequests.velero.io: attempting to create resource client

CustomResourceDefinition/serverstatusrequests.velero.io: created

CustomResourceDefinition/volumesnapshotlocations.velero.io: attempting to create resource

CustomResourceDefinition/volumesnapshotlocations.velero.io: attempting to create resource client

CustomResourceDefinition/volumesnapshotlocations.velero.io: created

Waiting for resources to be ready in cluster...

Namespace/velero: attempting to create resource

Namespace/velero: attempting to create resource client

Namespace/velero: created

ClusterRoleBinding/velero: attempting to create resource

ClusterRoleBinding/velero: attempting to create resource client

ClusterRoleBinding/velero: created

ServiceAccount/velero: attempting to create resource

ServiceAccount/velero: attempting to create resource client

ServiceAccount/velero: created

Secret/cloud-credentials: attempting to create resource

Secret/cloud-credentials: attempting to create resource client

Secret/cloud-credentials: created

BackupStorageLocation/default: attempting to create resource

BackupStorageLocation/default: attempting to create resource client

BackupStorageLocation/default: created

VolumeSnapshotLocation/default: attempting to create resource

VolumeSnapshotLocation/default: attempting to create resource client

VolumeSnapshotLocation/default: created

Deployment/velero: attempting to create resource

Deployment/velero: attempting to create resource client

Deployment/velero: created

DaemonSet/node-agent: attempting to create resource

DaemonSet/node-agent: attempting to create resource client

DaemonSet/node-agent: created

Velero is installed! ⛵ Use 'kubectl logs deployment/velero -n velero' to view the status.

thulasiraman_ilangovan@cloudshell:~$

Step 2: Verify Backup Availability

Check the availability of your previously-saved backups. If the credentials or bucket information does not match, the backups cannot be seen:

Command

velero get backup | grep 13-09-23

Output

mongo-backup-13-09-23 Completed 0 0 2023-09-13 13:15:32 +0000 UTC 29d default <none>

Command

kubectl get backupstoragelocation -n velero

Output

NAME PHASE LAST VALIDATED AGE DEFAULT

default Available 23s 3m32s true

Step 3: Restore Using Velero CLI

Initiate the restore process using Velero CLI with the following command:

Command

velero restore create mongo-restore-13-09-23 --from-backup mongo-backup-13-09-23

Output

Restore request "mongo-restore-13-09-23" submitted successfully.

Run `velero restore describe mongo-restore-13-09-23` or `velero restore logs mongo-restore-13-09-23` for more details.

Step 4: Check Restore Status

You can check the status of the restore process by using the velero get restore command.

velero get restore

When Velero performs a restore, it deploys an init container within the application pod, responsible for restoring the volume. Initially, the restore status will be InProgress.

note

Your storage class was originally set to cstor-csi-disk because you imported this PVC from a cStor volume, the status might temporarily stay as In Progress and your PVC will be in Pending status.

Step 5: Backup PVC and Change Storage Class

• Retrieve the current configuration of the PVC which is in Pending status using the following command:

kubectl get pvc mongodb-persistent-storage-claim-mongod-0 -o yaml > pvc-mongo.yaml

• Confirm that the PVC configuration has been saved by checking its existence with this command:

ls -lrt | grep pvc-mongo.yaml

• Edit the pvc-mongo.yaml file to update its storage class. Below is the modified PVC configuration with mayastor-single-replica set as the new storage class:

note

The statefulset for Mongo will still have the cstor-csi-disk storage class at this point. This will be addressed in the further steps.

apiVersion: v1

kind: PersistentVolumeClaim

metadata:

finalizers:

- kubernetes.io/pvc-protection

labels:

role: mongo

velero.io/backup-name: mongo-backup-13-09-23

velero.io/restore-name: mongo-restore-13-09-23

name: mongodb-persistent-storage-claim-mongod-0

namespace: default

spec:

accessModes:

- ReadWriteOnce

resources:

requests:

storage: 3Gi

storageClassName: mayastor-single-replica

volumeMode: Filesystem

Step 6: Resolve Issue where PVC is Pending

• Begin by deleting the problematic PVC with the following command:

kubectl delete pvc mongodb-persistent-storage-claim-mongod-0

• Once the PVC has been successfully deleted, you can recreate it using the updated configuration from the pvc-mongo.yaml file. Apply the new configuration with the following command:

kubectl apply -f pvc-mongo.yaml

Step 7: Check Velero Init Container

After recreating the PVC with Mayastor storageClass, you will observe the presence of a Velero initialization container within the application pod. This container is responsible for restoring the required volumes.

You can check the status of the restore operation by running the following command:

kubectl describe pod <enter_your_pod_name>

The output will display the pods' status, including the Velero initialization container. Initially, the status might show as "Init:0/1," indicating that the restore process is in progress.

You can track the progress of the restore by running:

Command

velero get restore

Output

NAME BACKUP STATUS STARTED COMPLETED ERRORS WARNINGS CREATED SELECTOR

mongo-restore-13-09-23 mongo-backup-13-09-23 Completed 2023-09-13 13:56:19 +0000 UTC 2023-09-13 14:06:09 +0000 UTC 0 4 2023-09-13 13:56:19 +0000 UTC <none>

You can then verify the data restoration by accessing your MongoDB instance. In the provided example, we used the "mongosh" shell to connect to the MongoDB instance and check the databases and their content. The data should reflect what was previously backed up from the cStor storage.

mongosh mongodb://admin:admin@mongod-0.mongodb-service.default.svc.cluster.local:27017

Step 8: Monitor Pod Progress

Due to the statefulset's configuration with three replicas, you will notice that the mongo-1 pod is created but remains in a Pending status. This behavior is expected as we have the storage class set to cStor in statefulset configuration.

Step 9: Capture the StatefulSet Configuration and Modify Storage Class

Capture the current configuration of the StatefulSet for MongoDB by running the following command:

kubectl get sts mongod -o yaml > sts-mongo-original.yaml

This command will save the existing StatefulSet configuration to a file named sts-mongo-original.yaml. Next, edit this YAML file to change the storage class to mayastor-single-replica.

apiVersion: apps/v1

kind: StatefulSet

metadata:

annotations:

backup.velero.io/backup-volumes: mongodb-persistent-storage-claim

meta.helm.sh/release-name: mongo

meta.helm.sh/release-namespace: default

generation: 1

labels:

app.kubernetes.io/managed-by: Helm

velero.io/backup-name: mongo-backup-13-09-23

velero.io/restore-name: mongo-restore-13-09-23

name: mongod

namespace: default

spec:

podManagementPolicy: OrderedReady

replicas: 3

revisionHistoryLimit: 10

selector:

matchLabels:

role: mongo

serviceName: mongodb-service

template:

metadata:

creationTimestamp: null

labels:

environment: test

replicaset: rs0

role: mongo

spec:

containers:

- command:

- mongod

- --bind_ip

- 0.0.0.0

- --replSet

- rs0

env:

- name: MONGO_INITDB_ROOT_USERNAME

valueFrom:

secretKeyRef:

key: username

name: secrets

- name: MONGO_INITDB_ROOT_PASSWORD

valueFrom:

secretKeyRef:

key: password

name: secrets

image: mongo:latest

imagePullPolicy: Always

lifecycle:

postStart:

exec:

command:

- /bin/sh

- -c

- sleep 90 ; ./tmp/scripts/script.sh > /tmp/script-log

name: mongod-container

ports:

- containerPort: 27017

protocol: TCP

resources: {}

terminationMessagePath: /dev/termination-log

terminationMessagePolicy: File

volumeMounts:

- mountPath: /data/db

name: mongodb-persistent-storage-claim

- mountPath: /tmp/scripts

name: mongo-scripts

dnsPolicy: ClusterFirst

restartPolicy: Always

schedulerName: default-scheduler

securityContext: {}

terminationGracePeriodSeconds: 10

volumes:

- configMap:

defaultMode: 511

name: mongo-replica

name: mongo-scripts

updateStrategy:

type: RollingUpdate

volumeClaimTemplates:

- apiVersion: v1

kind: PersistentVolumeClaim

metadata:

annotations:

volume.beta.kubernetes.io/storage-class: mayastor-single-replica #Make the change here

creationTimestamp: null

name: mongodb-persistent-storage-claim

spec:

accessModes:

- ReadWriteOnce

resources:

requests:

storage: 3Gi

volumeMode: Filesystem

Step 10: Delete StatefulSet (Cascade=False)

Delete the StatefulSet while preserving the pods with the following command:

kubectl delete sts mongod --cascade=false

You can run the following commands to verify the status:

kubectl get sts

kubectl get pods

kubectl get pvc

Step 11: Deleting Pending Secondary Pods and PVCs

Delete the MongoDB Pod mongod-1.

kubectl delete pod mongod-1

Delete the Persistent Volume Claim (PVC) for mongod-1.

kubectl delete pvc mongodb-persistent-storage-claim-mongod-1

Step 12: Recreate StatefulSet

Recreate the StatefulSet with the Yaml file.

Command

kubectl apply -f sts-mongo-mayastor.yaml

Output

statefulset.apps/mongod created

Command

kubectl get pods

Output

NAME READY STATUS RESTARTS AGE

mongo-client-758ddd54cc-h2gwl 1/1 Running 0 31m

mongod-0 1/1 Running 0 31m

mongod-1 1/1 Running 0 7m54s

mongod-2 1/1 Running 0 6m13s

ycsb-775fc86c4b-kj5vv 1/1 Running 0 31m

Command

kubectl mayastor get volumes

Output

ID REPLICAS TARGET-NODE ACCESSIBILITY STATUS SIZE THIN-PROVISIONED ALLOCATED

f41c2cdc-5611-471e-b5eb-1cfb571b1b87 1 gke-mayastor-pool-2acd09ca-ppxw nvmf Online 3GiB false 3GiB

113882e1-c270-4c72-9c1f-d9e09bfd66ad 1 gke-mayastor-pool-2acd09ca-4v3z nvmf Online 3GiB false 3GiB

fb4d6a4f-5982-4049-977b-9ae20b8162ad 1 gke-mayastor-pool-2acd09ca-q30r nvmf Online 3GiB false 3GiB

Step 13: Verify Data Replication on Secondary DB

Verify data replication on the secondary database to ensure synchronization.

root@mongod-1:/# mongosh mongodb://admin:admin@mongod-1.mongodb-service.default.svc.cluster.local:27017

Current Mongosh Log ID: 6501c744eb148521b3716af5

Connecting to: mongodb://<credentials>@mongod-1.mongodb-service.default.svc.cluster.local:27017/?directConnection=true&appName=mongosh+1.10.6

Using MongoDB: 7.0.1

Using Mongosh: 1.10.6

For mongosh info see: https://docs.mongodb.com/mongodb-shell/

------

The server generated these startup warnings when booting

2023-09-13T14:19:37.984+00:00: Using the XFS filesystem is strongly recommended with the WiredTiger storage engine. See http://dochub.mongodb.org/core/prodnotes-filesystem

2023-09-13T14:19:38.679+00:00: Access control is not enabled for the database. Read and write access to data and configuration is unrestricted

2023-09-13T14:19:38.679+00:00: You are running this process as the root user, which is not recommended

2023-09-13T14:19:38.679+00:00: vm.max_map_count is too low

------

rs0 [direct: secondary] test> use mydb

switched to db mydb

rs0 [direct: secondary] mydb> db.getMongo().setReadPref('secondary')

rs0 [direct: secondary] mydb> db.accounts.find()

[

{

_id: ObjectId("65019e2f183959fbdbd23f00"),

name: 'john',

total: '1058'

},

{

_id: ObjectId("65019e2f183959fbdbd23f01"),

name: 'jane',

total: '6283'

},

{

_id: ObjectId("65019e31183959fbdbd23f02"),

name: 'james',

total: '472'

}

]

rs0 [direct: secondary] mydb>

See Also

• Migration from Legacy Storage to Latest Storage Solution
• Migration for Distributed DB