Configuration options#

Using a configuration file#

k0s can be installed without a config file. In that case the default configuration will be used. You can, though, create and run your own non-default configuration (used by the k0s controller nodes).

Generate a yaml config file that uses the default settings.
```
k0s default-config > k0s.yaml
```
Modify the new yaml config file according to your needs, refer to Configuration file reference below.

Install k0s with your new config file.

sudo k0s install controller -c /path/to/your/config/file

If you need to modify your existing configuration later on, you can change your config file also when k0s is running, but remember to restart k0s to apply your configuration changes.
```
sudo k0s stop
sudo k0s start
```

Configuration file reference#

CAUTION: As many of the available options affect items deep in the stack, you should fully understand the correlation between the configuration file components and your specific environment before making any changes.

A YAML config file follows, with defaults as generated by the k0s default-config command:

apiVersion: k0s.k0sproject.io/v1beta1
kind: Cluster
metadata:
  name: k0s
spec:
  api:
    address: 192.168.68.104
    port: 6443
    k0sApiPort: 9443
    externalAddress: my-lb-address.example.com
    sans:
      - 192.168.68.104
  storage:
    type: etcd
    etcd:
      peerAddress: 192.168.68.104
  network:
    podCIDR: 10.244.0.0/16
    serviceCIDR: 10.96.0.0/12
    provider: kuberouter
    calico: null
    kuberouter:
      mtu: 0
      peerRouterIPs: ""
      peerRouterASNs: ""
      autoMTU: true
  podSecurityPolicy:
    defaultPolicy: 00-k0s-privileged
  telemetry:
    enabled: true
  installConfig:
    users:
      etcdUser: etcd
      kineUser: kube-apiserver
      konnectivityUser: konnectivity-server
      kubeAPIserverUser: kube-apiserver
      kubeSchedulerUser: kube-scheduler
  images:
    konnectivity:
      image: us.gcr.io/k8s-artifacts-prod/kas-network-proxy/proxy-agent
      version: v0.0.16
    metricsserver:
      image: gcr.io/k8s-staging-metrics-server/metrics-server
      version: v0.3.7
    kubeproxy:
      image: k8s.gcr.io/kube-proxy
      version: v1.21.5
    coredns:
      image: docker.io/coredns/coredns
      version: 1.7.0
    calico:
      cni:
        image: docker.io/calico/cni
        version: v3.18.1
      node:
        image: docker.io/calico/node
        version: v3.18.1
      kubecontrollers:
        image: docker.io/calico/kube-controllers
        version: v3.18.1
    kuberouter:
      cni:
        image: docker.io/cloudnativelabs/kube-router
        version: v1.2.1
      cniInstaller:
        image: quay.io/k0sproject/cni-node
        version: 0.1.0
    default_pull_policy: IfNotPresent
  konnectivity:
    agentPort: 8132
    adminPort: 8133

`spec` Key Detail#

`spec.api`#

Element	Description
`externalAddress`	The loadbalancer address (for k0s controllers running behind a loadbalancer). Configures all cluster components to connect to this address and also configures this address for use when joining new nodes to the cluster.
`address`	Local address on wihich to bind an API. Also serves as one of the addresses pushed on the k0s create service certificate on the API. Defaults to first non-local address found on the node.
`sans`	List of additional addresses to push to API servers serving the certificate.
`extraArgs`	Map of key-values (strings) for any extra arguments to pass down to Kubernetes api-server process.
`port`¹	Custom port for kube-api server to listen on (default: 6443)
`k0sApiPort`¹	Custom port for k0s-api server to listen on (default: 9443)

¹ If port and k0sApiPort are used with the externalAddress element, the loadbalancer serving at externalAddress must listen on the same ports.

`spec.storage`#

Element	Description
`type`	Type of the data store (valid values:`etcd` or `kine`). Note: Type `etcd` will cause k0s to create and manage an elastic etcd cluster within the controller nodes.
`etcd.peerAddress`	Node address used for etcd cluster peering.
`kine.dataSource`	kine datasource URL.

`spec.network`#

Element	Description
`provider`	Network provider (valid values: `calico`, `kuberouter`, or `custom`). For `custom`, you can push any network provider (default: `kuberouter`). Be aware that it is your responsibility to configure all of the CNI-related setups, including the CNI provider itself and all necessary host levels setups (for example, CNI binaries). Note: Once you initialize the cluster with a network provider the only way to change providers is through a full cluster redeployment.
`podCIDR`	Pod network CIDR to use in the cluster.
`serviceCIDR`	Network CIDR to use for cluster VIP services.

`spec.network.calico`#

Element	Description
`mode`	`vxlan` (default) or `ipip`
`vxlanPort`	The UDP port for VXLAN (default: `4789`).
`vxlanVNI`	The virtual network ID for VXLAN (default: `4096`).
`mtu`	MTU for overlay network (default: `0`, which causes Calico to detect optimal MTU during bootstrap).
`wireguard`	Enable wireguard-based encryption (default: `false`). Your host system must be wireguard ready (refer to the Calico documentation for details).
`flexVolumeDriverPath`	The host path for Calicos flex-volume-driver(default: `/usr/libexec/k0s/kubelet-plugins/volume/exec/nodeagent~uds`). Change this path only if the default path is unwriteable (refer to Project Calico Issue #2712 for details). Ideally, you will pair this option with a custom `volumePluginDir` in the profile you use for your worker nodes.
`ipAutodetectionMethod`	Use to force Calico to pick up the interface for pod network inter-node routing (default: `""`, meaning not set, so that Calico will instead use its defaults). For more information, refer to the Calico documentation.

`spec.network.kuberouter`#

Element	Description
`autoMTU`	Autodetection of used MTU (default: `true`).
`mtu`	Override MTU setting, if `autoMTU` must be set to `false`).
`peerRouterIPs`	Comma-separated list of global peer addresses.
`peerRouterASNs`	Comma-separated list of global peer ASNs.

Note: Kube-router allows many networking aspects to be configured per node, service, and pod (for more information, refer to the Kube-router user guide).

`spec.podSecurityPolicy`#

Use the spec.podSecurityPolicy key to configure the default PSP.

k0s creates two PSPs out-of-the-box:

PSP	Description
`00-k0s-privileged`	Default; no restrictions; used also for Kubernetes/k0s level system pods.
`99-k0s-restricted`	Does not allow any host namespaces or root users, nor any bind mounts from the host

Note: Users can create supplemental PSPs and bind them to users / access accounts as necessary.

`spec.controllerManager`#

Element	Description
`extraArgs`	Map of key-values (strings) for any extra arguments you want to pass down to the Kubernetes controller manager process.

`spec.scheduler`#

Element	Description
`extraArgs`	Map of key-values (strings) for any extra arguments you want to pass down to Kubernetes scheduler process.

`spec.workerProfiles`#

Array of spec.workerProfiles.workerProfile. Each element has following properties:

Property	Description
`name`	String; name to use as profile selector for the worker process
`values`	Mapping object

For each profile, the control plane creates a separate ConfigMap with kubelet-config yaml. Based on the --profile argument given to the k0s worker, the corresponding ConfigMap is used to extract the kubelet-config.yaml file. values are recursively merged with default kubelet-config.yaml

Note that there are several fields that cannot be overridden:

clusterDNS
clusterDomain
apiVersion
kind

Examples#

mapping:

spec:
  workerProfiles:
    - name: custom-role
      values:
         key: value
         mapping:
             innerKey: innerValue

Custom volumePluginDir:

spec:
  workerProfiles:
    - name: custom-role
      values:
         volumePluginDir: /var/libexec/k0s/kubelet-plugins/volume/exec

`spec.images`#

Nodes under the images key all have the same basic structure:

spec:
  images:
    coredns:
      image: docker.io/coredns/coredns
      version: 1.7.0

Available keys#

spec.images.konnectivity
spec.images.metricsserver
spec.images.kubeproxy
spec.images.coredns
spec.images.calico.cni
spec.images.calico.flexvolume
spec.images.calico.node
spec.images.calico.kubecontrollers
spec.images.kuberouter.cni
spec.images.kuberouter.cniInstaller
spec.images.repository¹

¹ If spec.images.repository is set and not empty, every image will be pulled from images.repository

If spec.images.default_pull_policy is set and not empty, it will be used as a pull policy for each bundled image.

Example#

images:
  repository: "my.own.repo"
  konnectivity:
    image: calico/kube-controllers
    version: v3.16.2
  metricsserver:
    image: gcr.io/k8s-staging-metrics-server/metrics-server
    version: v0.3.7

In the runtime the image names are calculated as my.own.repo/calico/kube-controllers:v3.16.2 and my.own.repo/k8s-staging-metrics-server/metrics-server. This only affects the the imgages pull location, and thus omitting an image specification here will not disable component deployment.

`spec.extensions.helm`#

spec.extensions.helm is the config file key in which you configure the list of Helm repositories and charts to deploy during cluster bootstrap (for more information, refer to Helm Charts).

`spec.konnectivity`#

The spec.konnectivity key is the config file key in which you configure Konnectivity-related settings.

agentPort agent port to listen on (default 8132)
adminPort admin port to listen on (default 8133)

`spec.telemetry`#

To improve the end-user experience k0s is configured by defaul to collect telemetry data from clusters and send it to the k0s development team. To disable the telemetry function, change the enabled setting to false.

The telemetry interval is ten minutes.

spec:
    telemetry:
      enabled: true

Configuration options#

Using a configuration file#

Configuration file reference#

spec Key Detail#

spec.api#

spec.storage#

spec.network#

spec.network.calico#

spec.network.kuberouter#

spec.podSecurityPolicy#

spec.controllerManager#

spec.scheduler#

spec.workerProfiles#