Configuration options for worker nodes

Although the k0s worker command does not take in any special yaml configuration, there are still methods for configuring the workers to run various components.

Node labels

The k0s worker command accepts the --labels flag, with which you can make the newly joined worker node the register itself, in the Kubernetes API, with the given set of labels.

For example, running the worker with k0s worker --token-file k0s.token --labels="k0sproject.io/foo=bar,k0sproject.io/other=xyz" results in:

$ kubectl get node --show-labels
NAME      STATUS     ROLES    AGE   VERSION        LABELS
worker0   NotReady   <none>   10s   v1.20.2-k0s1   beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,k0sproject.io/foo=bar,k0sproject.io/other=xyz,kubernetes.io/arch=amd64,kubernetes.io/hostname=worker0,kubernetes.io/os=linux

Note: Setting the labels is only effective on the first registration of the node. Changing the labels thereafter has no effect.

Kubelet args

The k0s worker command accepts a generic flag to pass in any set of arguments for kubelet process.

For example, running k0s worker --token-file=k0s.token --kubelet-extra-args="--node-ip=1.2.3.4 --address=0.0.0.0" passes in the given flags to kubelet as-is. As such, you must confirm that any flags you are passing in are properly formatted and valued as k0s will not validate those flags.

IPTables Mode

k0s detects iptables backend automatically based on the existing records. On a brand-new setup, iptables-nft will be used.
There is a --iptables-mode flag to specify the mode explicitly. Valid values: nft, legacy and auto (default).

k0s worker --iptables-mode=nft