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K3S Backup

Backup and Restore for Single-Node K3s Cluster Using SQLite​

Ansible Playbook

When working with a single-node K3s cluster, the default datastore is SQLite, which is a lightweight, file-based database. Unfortunately, K3s does not provide specialized tools for backing up SQLite in single-node configurations.

In contrast, if you're running a multi-node (High Availability) cluster using etcd as the datastore, K3s offers a convenient k3s etcd-snapshot command for backups and recovery. However, this tool is not applicable for single-node clusters where SQLite is the default datastore.

Why Manually Back Up?​

SQLite backups in K3s require manual steps because:

  • SQLite is a simple, file-based database, so backing it up is as easy as copying key directories.
  • K3s doesn't provide automatic backup utilities for this.

The good news is that manual backups are not too complicated. In this guide, we'll walk you through how to perform a manual backup and restore of K3s data using simple tools.

Backup and Restore for Single-Node K3s (SQLite)​

Backup Process:​

  1. Identify Critical Files:
  • SQLite Database: /var/lib/rancher/k3s/server/db/
  • TLS Certificates: /var/lib/rancher/k3s/server/tls/
  • Join Token: /var/lib/rancher/k3s/server/token
  1. Create Backup Folder on Local Machine:
mkdir -p ~/k3s-backups/
  1. Copy Files from K3s Server to Local Machine:
scp -r user@master_node:/var/lib/rancher/k3s/server/db ~/k3s-backups/
scp -r user@master_node:/var/lib/rancher/k3s/server/tls ~/k3s-backups/
scp user@master_node:/var/lib/rancher/k3s/server/token ~/k3s-backups/
  1. (Optional) Compress the Backup:
tar -czf ~/k3s-backups/k3s-backup-$(date +%F_%T).tar.gz -C ~/k3s-backups db tls token

Restore Process:​

  1. Stop K3s:
sudo systemctl stop k3s
  1. Upload Backup from Local Machine to K3s Node:
scp -r ~/k3s-backups/db user@master_node:/var/lib/rancher/k3s/server/
scp -r ~/k3s-backups/tls user@master_node:/var/lib/rancher/k3s/server/
scp ~/k3s-backups/token user@master_node:/var/lib/rancher/k3s/server/
  1. Ensure Correct Permissions:
sudo chown -R root:root /var/lib/rancher/k3s/server/db /var/lib/rancher/k3s/server/tls
sudo chown root:root /var/lib/rancher/k3s/server/token
sudo chmod 0600 /var/lib/rancher/k3s/server/token
  1. Start K3s:
sudo systemctl start k3s
  1. Verify Cluster Health:
kubectl get nodes
kubectl get pods --all-namespaces

Summary:​

  • Backup: Copy db/, tls/, and token from /var/lib/rancher/k3s/server/ to your local machine.

  • Restore: Stop K3s, upload those files back to the node, ensure permissions, and start K3s again.