Rancher Longhorn Notes

Outline

• Overview
• Install Longhorn in Rancher
• Using Minio for Backups
• Setting up Longhorn to use Minio for Backups
• Taking a Backup of a PVC
• Restoring a PVC

Overview

I started using Longhorn as a Persistent Storage Class in Kubernetes. There were a few things I really liked about it:

• Easy to set up
• Supports backups and recovery of a Kubernetes PVC

Install Longhorn in Rancher

Installing Longhorn in a Rancher Kubernetes cluster is easy. You can install it from Rancher's App Catalog. Once Longhorn is installed you can use it as a Storage Class for your PVCs.

Using Minio for Backups

I set up Minio for storing PVC backups offsite. Minio uses the Amazon S3 protocol. I created a bucket in Minio called backup. Longhorn will be set up to send backups to it.

Setting up Longhorn to use Minio for Backups

Secret

Longhorn will need a Kubernetes Secret in the longhorn namespace to authenticate with Minio. This was tricky to set up because the values needed to work weren't so intuitive.

apiVersion: v1
data:
  AWS_ACCESS_KEY_ID: QUtJQUlPU0ZPRE5ON0VYQU1QTEU= #this is base64 coded
  AWS_ENDPOINTS: aHR0cDovLzQwLjEzOC4zNS41Mg== #this is a base64 encoded URL http://40.138.35.52
  AWS_SECRET_ACCESS_KEY: d0phbHJYVXRuRkVNSS9LN01ERU5HL2JQeFJmaUNZRVhBTVBMRUtFWQ== #this is base64 coded
kind: Secret
metadata:
  name: minio
  namespace: longhorn-system
type: Opaque

Longhorn Config

Taking a Backup of a PVC

After Longhorn is configured to point to Minio you can take a backup from the Volume page.

Restoring a PVC

The PVCs can be restored from the Backup age.

The restore process is not very intuitive. These are the steps I went through to restore a PVC.

1. Delete the app (Chartmuseum in this case) to simulate a failure.
2. Create a Disaster Recovery Volume from the Backup page.
3. Activate the Disaster Recovery Volume from the Volumes page.
4. Create a PV/PVC from the Volumes page.
5. DO NOT attach the new PV/PVC from the Volumes page (this happens automatically in the next step).
6. Reinstall the app you deleted from step 1. and select the PV/PVC created from step 4.
7. The data should be restored at this point.