k3s-systemd-service-configuration.md

K3S Systemd Service Configuration.

The systemd service configuration file contains some additional configuration like mentioned below.
Various configuration options for k3s server can be found here.

• Add-ons configuration.

  Some default additional add-ons like traefik and metrics-server are currently disabled. If requires then remove following from the systemd file.

  --disable=traefik --disable=metrics-server
  

• CIDR Network range.

  k3s uses default CIDR network range for internal communication. If changes requires then update different CIDR range in the systemd file.

  --cluster-cidr="10.42.0.0/16" --service-cidr="10.43.0.0/16"
  

• NodePort range.

  k3s uses a port range from systems dynamic port range. If need to modify this to contain only small number of ports or some other range then update different ports range in the systemd file.

  --service-node-port-range="30000-32767"
  

• Data storage.

  k3s uses default data directory from root (/) partition. On some cases it may need to change this to some other path or additional mounted drive instead of OS drive. If changes requires then update different directory in the systemd file.

  --data-dir="/var/lib/rancher"
  

  If this directory is changed to some other path then will need to create a symlink since k3s default uses some configuration files from default data directory.

  ln -sf PATH_TO_STORAGE_DIR_FOR_K3S /var/lib/rancher

• Configuration for kubelet.

  A detailed configuration can be found here.

  • Log configuration for pods. If changes requires then update different directory in the systemd file.

  --kubelet-arg "--container-log-max-files=2"
  --kubelet-arg "--container-log-max-size=10Mi"
  

  • Image garbage collection configuration. If changes requires then update different directory in the systemd file.

  --kubelet-arg "--image-gc-high-threshold=60"
  --kubelet-arg "--image-gc-low-threshold=50"