kube-volume-freezer

kube-volume-freezer

Freeze Pod Volumes in Kubernetes for the purpose of producing a live snapshot.

Use-Case

• You want to sync and freeze one or multiple Kubernetes Pod Volumes before creating a live snapshot without adding additional capabilities to your Pods. (GCE-Guide on creating snapshots)

Architecture

• kvf-minion is run on every Node with required privileges and perform the actual syncing, freezing and thawing of local Volumes on the host.
• kvf-apiserver delegates client requests to the correct Minion.
• kvfctl is a command-line interface to the kvf-apiserver.

Install

The folder manifests contains an example deployment of kube-volume-freezer with token protected Minions and API server.

Steps to install:

• Set your base64 encoded tokens in the kcf-secret.yaml file.
• Add kvf-secret.yaml, kvf-daemonset.yaml, kvf-deployment.yaml and kvf-svc.yaml to your Kubernetes.

Example

The following example shows how to create a live snapshot from a running system on GCE using kubectl, kvfctl, and gcloud.

#!/bin/bash
# Open a local port to the kube-volume-freezer service.
# This is not needed when running inside a Kubernetes Cluster.
kubectl port-forward kube-volume-freezer-master-1053963144-7uxa2 8080:8080 &
PID=$!

# Freeze Volume named "data" in Pod "gitlab-3323024633-063kf".
kvfctl freeze --address localhost:8080 --token "my-token" gitlab-3323024633-063kf data

# Create snapshot on GCE associated with the Pod.
gcloud compute disks snapshot gitlab-disk --zone europe-west1-b --snapshot-names "gitlab-disk-$(date +"%Y%m%d%H%M%S")"

# Thaw Volume.
kvfctl thaw --address localhost:8080 --token "my-token" gitlab-3323024633-063kf data

# Close local port.
kill -TERM ${PID}

In a more complex example you can use kubectl to detect persistent disks of different deployments automatically and perform live snapshotting simultaneously.

Library

• golang client