🪶 K3S Cheat-Sheet
K3S is a lightweight Kubernetes distribution designed for IoT and edge computing environments. It’s production-ready and easy to install with a binary size under 100 MB, consuming less memory compared to traditional Kubernetes setups.
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Project Homepage: K3s.io
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Documentation: K3s Documentation
🔍 Overview
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Product Type: Lightweight Kubernetes Distribution
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Focus: K3S is tailored for environments that need a small footprint and minimal resource consumption, such as IoT, edge computing, and small clusters.
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Single-Node Setup: Ideal for development and testing
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Multi-Node Setup: High Availability (HA) configurations with embedded or external databases
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Ease of Installation: Simple and quick installation with automated scripts
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🔧 Installation
You can install K3S using several methods: with an external database, embedded database, or as a single-node setup.
📊 K3s with External DB
Set up a High Availability (HA) K3s cluster backed by an external database like MySQL, PostgreSQL, or etcd.
🗃️ Install Database
- First, install MariaDB or your preferred database.
🖥️ Install Servers
To install K3s with an external database:
curl -sfL https://get.k3s.io | sh -s - server \
--token=YOUR-SECRET \
--datastore-endpoint='mysql://user:pass@tcp(ipaddress:3306)/dbname' \
--node-taint CriticalAddonsOnly=true:NoExecute \
--tls-san your-dns-name --tls-san your-lb-ip-addressInfo
The
--node-taintflag ensures that your server node won’t run workloads, only the control plane.
🔒 SSL Certificates
To avoid certificate errors, you should use the --tls-san YOUR_IP_OR_HOSTNAME_HERE option to add extra IPs or hostnames to the TLS certificate.
🚀 Install Agents
You can install agents on additional nodes:
curl -sfL https://get.k3s.io | sh -s - agent \
--server https://your-lb-ip-address:6443 \
--token YOUR-SECRET💾 K3s with Embedded DB
Set up an HA K3s cluster using K3s’s built-in distributed database (etcd).
🖥️ Install the First Server
curl -sfL https://get.k3s.io | sh -s - server \
--token=YOUR-SECRET \
--tls-san your-dns-name --tls-san your-lb-ip-address \
--cluster-initTip
The
--tls-sanoption ensures no SSL certificate errors when accessing the server via IP or hostname.
🏗️ Install Additional Servers
To add more servers:
curl -sfL https://get.k3s.io | sh -s - server \
--token=YOUR-SECRET \
--tls-san your-dns-name --tls-san your-lb-ip-address \
--server https://IP-OF-THE-FIRST-SERVER:6443The --cluster-init option initializes the HA cluster with an embedded etcd database. You need at least 3 nodes for fault tolerance.
🗓️ Fault Tolerance Table
| Total Number of Nodes | Failed Node Tolerance |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 1 |
| 5 | 2 |
| 6 | 2 |
🖥️ Install Agents
To install agent nodes:
curl -sfL https://get.k3s.io | sh -s - agent \
--server https://your-lb-ip-address:6443 \
--token YOUR-SECRET⚙️ K3s Single Node
Set up K3s as a single-node installation.
Warning
This setup is ideal for testing and development but may not be suitable for production.
🛠️ Manage K3S
💻 Management on Server Nodes
Use the K3S-specific kubectl to manage your cluster:
k3s kubectl📜 Download Kube Config
You can download the kubeconfig file from:
/etc/rancher/k3s/k3s.yaml
💾 Database Backups
🧳 etcd Snapshots
K3S stores etcd snapshots in the following directory:
/var/lib/rancher/k3s/server/db/snapshots
Tip
Regular backups of the etcd database are crucial for disaster recovery.
📚 Resources
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Official Website: K3s Official Website
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Documentation: K3s Documentation
🔁 Related
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Getting Started with Kubernetes — A guide to setting up and managing Kubernetes clusters.
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Using Kubernetes with Helm — Dive deeper into Helm’s features for managing Kubernetes applications.
🌍 Explore More
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Explore Kubernetes Networking to learn about networking in a containerized environment.
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Dive into K3s Troubleshooting for advanced troubleshooting techniques when managing your K3s clusters.