Build K3s Cluster

Install

Steps:

1. Present config.yaml for the agent or server.
2. Run a convenient script for installing the k3s.
3. Using systemctl to manage the k3s service.

1. Config.yaml

Add config.yaml to /etc/rancher/k3s/config.yaml

Server config in server node

# node-name in k8s needing lowercase
node-name: host-01

# additional domain for certificate, it's necessary when you need to connect using domain
tls-san: "host-01.davidhsaiou.com"

# the network interface to bind (optional)
flannel-iface: wg0

# prepare certificate for further agent to join
cluster-init: true

# let the kubeconfig can read from none root user
write-kubeconfig-mode: 644

# allow unsafe sysctl config
# see kubelet conf
kubelet-arg:
  - "allowed-unsafe-sysctls=net.ipv4.tcp_syn_retries,net.ipv4.ip_forward"

While inited, you can get the server token from /var/lib/rancher/k3s/server/node-token

Agent config in agent node

 # node name in k8s needing lowercase
node-name: pc-node-1

 # the network interface to bind (optional)
flannel-iface: wg0

 # server location with K8s apiserver port.
server: https://10.1.0.1:6443

# node label config (optional)
node-label: 
  - "gpu=true"

# node taint config (optional)
node-taint: 
  - "laptop=true:NoSchedule"

# the server token in /var/lib/rancher/k3s/server/node-token
token: <K3s server token>

 # allow unsafe sysctl config
 # see kubelet conf
kubelet-arg:
  - "allowed-unsafe-sysctls=net.ipv4.tcp_syn_retries,net.ipv4.ip_forward"

2. Install Script

Server node

curl -sfL https://get.k3s.io | sh -s -

Agent node

curl -sfL https://get.k3s.io | sh -s - agent 

3. Manage K3s using systemctl

Server Service name is k3s
Agent Service name is k3s-agent

Checking Status

sudo systemctl status k3s

Stop k3s

sudo systemctl stop k3s

Restart k3s

sudo systemctl restart k3s

Reference

• K3s Quick Start