VolSync is a Kubernetes operator that asynchronously replicates persistent volumes between clusters using rsync or rclone. It also supports creating backups of persistent volumes via restic.

Installation:

Install VolSync via Helm:

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helm repo add backube https://backube.github.io/helm-charts/
helm install --create-namespace -n volsync-system volsync backube/volsync

Migrating Data into Kubernetes:

VolSync provides a CLI tool (kubectl-volsync) for migrating data from external storage into Kubernetes PersistentVolumes.

Step 1: Install VolSync CLI

Install the CLI using Krew:

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kubectl krew install volsync

Step 2: Create Migration Destination

Create a namespace and migration destination:

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kubectl create ns destination
kubectl volsync migration create -r mig-example \
  --capacity 2Gi \
  --accessmodes ReadWriteOnce \
  --storageclass standard-csi \
  --pvcname destination/mydata

This creates a 2Gi PVC named mydata in the destination namespace.

Step 3: Copy Data into PVC

Migrate data from external storage (e.g., local directory):

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kubectl volsync migration rsync -r mig-example --source /tmp/data/

This synchronizes /tmp/data/ into the mydata PVC.

Step 4: Use Migrated Data

Deploy a pod to access the migrated data:

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apiVersion: v1
kind: Pod
metadata:
  name: data-consumer
  namespace: destination
spec:
  containers:
  - name: data-consumer
    image: busybox
    command: ["/bin/sh", "-c", "sleep 3600"]
    volumeMounts:
    - mountPath: "/data"
      name: mydata
  volumes:
  - name: mydata
    persistentVolumeClaim:
      claimName: mydata

Step 5: Clean Up

Remove migration resources after completion:

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kubectl volsync migration delete -r mig-example

For detailed documentation and advanced usage, see the VolSync documentation and GitHub repository.