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kamlesh merugu
kamlesh merugu

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Install k3s on Debian 11/12

#debian #k3s #containers

🧱 Prerequisites (Debian)

Works great on Debian 11 / 12 (including VPS, VM, bare metal).

1️⃣ Update the system 

sudo apt update &&sudo apt upgrade -y
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2️⃣ Install required basics 

sudo apt install -y curl ca-certificates gnupg
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3️⃣ Disable swap (required for Kubernetes) 

sudo sed -i '/ swap / s/^/#/' /etc/fstab
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🚀 Install k3s (Single-node Control Plane)

k3s is maintained by Rancher, and the install is famously one-liner simple.

🔹 Default install (recommended) with Traefik and custom kubeconfig mode 

curl -sfL https://get.k3s.io | INSTALL_K3S_EXEC="--disable traefik" K3S_KUBECONFIG_MODE="644" sh
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That’s it. Seriously.

✅ Verify Installation

Check k3s service 

sudo systemctl status k3s
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Check nodes 

sudo k3s kubectl get nodes
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You should see something like:

NAME        STATUS   ROLES                  AGEVERSION
debian      Ready    control-plane,master1m    v1.xx.x+k3s
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🧠 kubectl Setup (Optional but Recommended)

So you don’t have to type sudo k3s kubectl every time:

# Create the .kube directory in your home
mkdir -p $HOME/.kube

# Copy the k3s configuration to your local user directory
sudo cp /etc/rancher/k3s/k3s.yaml $HOME/.kube/config

# Change ownership of the config to your user
sudo chown $(id -u):$(id -g) $HOME/.kube/config

# Set the environment variable for the current session
export KUBECONFIG=$HOME/.kube/config

# Add the KUBECONFIG variable permanently to your profile
echo "export KUBECONFIG=$HOME/.kube/config" >> ~/.bashrc
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Test:

kubectl get pods -A
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🌐 Allow kubectl from Outside (Optional)

If you’re on a VPS and want remote access:

Edit:

sudo nano /etc/rancher/k3s/k3s.yaml
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Replace:

server:https://127.0.0.1:6443
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With:

server:https://<YOUR_SERVER_IP>:6443
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Restart:

sudo systemctl restart k3s
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➕ Add Worker Nodes (Agent)

On the server, get the token:

sudo cat /var/lib/rancher/k3s/server/node-token
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On the agent node:

curl -sfL https://get.k3s.io | \
K3S_URL=https://<SERVER_IP>:6443 \
K3S_TOKEN=<NODE_TOKEN> sh -
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Verify:

kubectl get nodes
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🔥 Common Useful Commands 

# All system pods
kubectl get pods -A

# Cluster info
kubectl cluster-info

# Stop / start k3s
sudo systemctl stop k3s
sudo systemctl start k3s
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🧹 Uninstall (If Needed)

Server 

/usr/local/bin/k3s-uninstall.sh
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Agent 

/usr/local/bin/k3s-agent-uninstall.sh
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