Configuration

This guide covers how to configure KIND cluster creation.

We know this is currently a bit lacking and will expand it over time - PRs welcome!

Contents 🔗︎

Getting Started 🔗︎

To configure kind cluster creation, you will need to create a YAML config file. This file follows Kubernetes conventions for versioning etc.

A minimal valid config is:

kind: Cluster
apiVersion: kind.x-k8s.io/v1alpha4

This config merely specifies that we are configuring a KIND cluster (kind: Cluster) and that the version of KIND’s config we are using is v1alpha4 (apiVersion: kind.x-k8s.io/v1alpha4).

Any given version of kind may support different versions which will have different options and behavior. This is why we must always specify the version.

This mechanism is inspired by Kubernetes resources and component config.

To use this config, place the contents in a file config.yaml and then run kind create cluster --config=config.yaml from the same directory.

You can also include a full file path like kind create cluster --config=/foo/bar/config.yaml.

The structure of the Cluster type is defined by a Go struct, which is described here.

A Note On CLI Parameters and Configuration Files 🔗︎

Unless otherwise noted, parameters passed to the CLI take precedence over their equivalents in a config file. For example, if you invoke:


`kind create cluster --name my-cluster`

The name my-cluster will be used regardless of the presence of that value in your config file.

Cluster-Wide Options 🔗︎

The following high level options are available.

NOTE: not all options are documented yet! We will fix this with time, PRs welcome!

Name Your Cluster 🔗︎

You can give your cluster a name by specifying it in your config:


`kind: Cluster apiVersion: kind.x-k8s.io/v1alpha4 name: app-1-cluster`

Feature Gates 🔗︎

Kubernetes feature gates can be enabled cluster-wide across all Kubernetes components with the following config:


`kind: Cluster apiVersion: kind.x-k8s.io/v1alpha4 featureGates: # any feature gate can be enabled here with "Name": true # or disabled here with "Name": false # not all feature gates are tested, however "CSIMigration": true`

kind: Cluster
apiVersion: kind.x-k8s.io/v1alpha4
featureGates:
  # any feature gate can be enabled here with "Name": true
  # or disabled here with "Name": false
  # not all feature gates are tested, however
  "CSIMigration": true

Runtime Config 🔗︎

Kubernetes API server runtime-config can be toggled using the runtimeConfig key, which maps to the --runtime-config kube-apiserver flag. This may be used to e.g. disable beta / alpha APIs.


`kind: Cluster apiVersion: kind.x-k8s.io/v1alpha4 runtimeConfig: "api/alpha": "false"`

Networking 🔗︎

Multiple details of the cluster’s networking can be customized under the networking field.

IP Family 🔗︎

KIND has support for IPv4, IPv6 and dual-stack clusters, you can switch from the default of IPv4 by setting:

IPv6 clusters 🔗︎

You can run IPv6 single-stack clusters using kind, if the host that runs the docker containers support IPv6. Most operating systems / distros have IPv6 enabled by default, but you can check on Linux with the following command:

sudo sysctl net.ipv6.conf.all.disable_ipv6

You should see:

net.ipv6.conf.all.disable_ipv6 = 0

If you are using Docker on Windows or Mac, you will need to use an IPv4 port forward for the API Server from the host because IPv6 port forwards don’t work on these platforms, you can do this with the following config:


`kind: Cluster apiVersion: kind.x-k8s.io/v1alpha4 networking: ipFamily: ipv6 apiServerAddress: 127.0.0.1`

On Linux all you need is:


`kind: Cluster apiVersion: kind.x-k8s.io/v1alpha4 networking: ipFamily: ipv6`

Dual Stack clusters 🔗︎

You can run dual stack clusters using kind 0.11+, on kubernetes versions 1.20+.


`kind: Cluster apiVersion: kind.x-k8s.io/v1alpha4 networking: ipFamily: dual`

API Server 🔗︎

The API Server listen address and port can be customized with:


`kind: Cluster apiVersion: kind.x-k8s.io/v1alpha4 networking: # WARNING: It is _strongly_ recommended that you keep this the default # (127.0.0.1) for security reasons. However it is possible to change this. apiServerAddress: "127.0.0.1" # By default the API server listens on a random open port. # You may choose a specific port but probably don't need to in most cases. # Using a random port makes it easier to spin up multiple clusters. apiServerPort: 6443`

kind: Cluster
apiVersion: kind.x-k8s.io/v1alpha4
networking:
  # WARNING: It is _strongly_ recommended that you keep this the default
  # (127.0.0.1) for security reasons. However it is possible to change this.
  apiServerAddress: "127.0.0.1"
  # By default the API server listens on a random open port.
  # You may choose a specific port but probably don't need to in most cases.
  # Using a random port makes it easier to spin up multiple clusters.
  apiServerPort: 6443

Security Goose Says:
NOTE: You should really think thrice before exposing your kind cluster publicly! kind does not ship with state of the art security or any update strategy (other than disposing your cluster and creating a new one)! We strongly discourage exposing kind to anything other than loopback.

Pod Subnet 🔗︎

You can configure the subnet used for pod IPs by setting


`kind: Cluster apiVersion: kind.x-k8s.io/v1alpha4 networking: podSubnet: "10.244.0.0/16"`

By default, kind uses 10.244.0.0/16 pod subnet for IPv4 and fd00:10:244::/56 pod subnet for IPv6.

Service Subnet 🔗︎

You can configure the Kubernetes service subnet used for service IPs by setting


`kind: Cluster apiVersion: kind.x-k8s.io/v1alpha4 networking: serviceSubnet: "10.96.0.0/12"`

By default, kind uses 10.96.0.0/16 service subnet for IPv4 and fd00:10:96::/112 service subnet for IPv6.

Disable Default CNI 🔗︎

KIND ships with a simple networking implementation (“kindnetd”) based around standard CNI plugins (ptp, host-local, …) and simple netlink routes.

This CNI also handles IP masquerade.

You may disable the default to install a different CNI. This is a power user feature with limited support, but many common CNI manifests are known to work, e.g. Calico.


`kind: Cluster apiVersion: kind.x-k8s.io/v1alpha4 networking: # the default CNI will not be installed disableDefaultCNI: true`

kube-proxy mode 🔗︎

You can configure the kube-proxy mode that will be used, between iptables, nftables (Kubernetes v1.31+), and ipvs. By default iptables is used


`kind: Cluster apiVersion: kind.x-k8s.io/v1alpha4 networking: kubeProxyMode: "nftables"`

To disable kube-proxy, set the mode to "none".

Nodes 🔗︎

The kind: Cluster object has a nodes field containing a list of node objects. If unset this defaults to:

nodes:
# one node hosting a control plane
- role: control-plane

You can create a multi node cluster with the following config:


`kind: Cluster apiVersion: kind.x-k8s.io/v1alpha4 # One control plane node and three "workers". # # While these will not add more real compute capacity and # have limited isolation, this can be useful for testing # rolling updates etc. # # The API-server and other control plane components will be # on the control-plane node. # # You probably don't need this unless you are testing Kubernetes itself. nodes: - role: control-plane - role: worker - role: worker - role: worker`

kind: Cluster
apiVersion: kind.x-k8s.io/v1alpha4
# One control plane node and three "workers".
#
# While these will not add more real compute capacity and
# have limited isolation, this can be useful for testing
# rolling updates etc.
#
# The API-server and other control plane components will be
# on the control-plane node.
#
# You probably don't need this unless you are testing Kubernetes itself.
nodes:
- role: control-plane
- role: worker
- role: worker
- role: worker

Per-Node Options 🔗︎

The following options are available for setting on each entry in nodes.

NOTE: not all options are documented yet! We will fix this with time, PRs welcome!

Kubernetes Version 🔗︎

You can set a specific Kubernetes version by setting the node’s container image. You can find available image tags on the releases page. Please include the @sha256: image digest from the image in the release notes, as seen in this example:


`kind: Cluster apiVersion: kind.x-k8s.io/v1alpha4 nodes: - role: control-plane image: kindest/node:v1.16.4@sha256:b91a2c2317a000f3a783489dfb755064177dbc3a0b2f4147d50f04825d016f55 - role: worker image: kindest/node:v1.16.4@sha256:b91a2c2317a000f3a783489dfb755064177dbc3a0b2f4147d50f04825d016f55`

kind: Cluster
apiVersion: kind.x-k8s.io/v1alpha4
nodes:
- role: control-plane
  image: kindest/node:v1.16.4@sha256:b91a2c2317a000f3a783489dfb755064177dbc3a0b2f4147d50f04825d016f55
- role: worker
  image: kindest/node:v1.16.4@sha256:b91a2c2317a000f3a783489dfb755064177dbc3a0b2f4147d50f04825d016f55

Reference

Note: Kubernetes versions are expressed as x.y.z, where x is the major version, y is the minor version, and z is the patch version, following Semantic Versioning terminology. For more information, see Kubernetes Release Versioning.

Extra Mounts 🔗︎

Extra mounts can be used to pass through storage on the host to a kind node for persisting data, mounting through code etc.

kind: Cluster
apiVersion: kind.x-k8s.io/v1alpha4
nodes:
- role: control-plane
  # add a mount from /path/to/my/files on the host to /files on the node
  extraMounts:
  - hostPath: /path/to/my/files
    containerPath: /files
  #
  # add an additional mount leveraging *all* of the config fields
  #
  # generally you only need the two fields above ...
  #
  - hostPath: /path/to/my/other-files/
    containerPath: /other-files
    # optional: if set, the mount is read-only.
    # default false
    readOnly: true
    # optional: if set, the mount needs SELinux relabeling.
    # default false
    selinuxRelabel: false
    # optional: set propagation mode (None, HostToContainer or Bidirectional)
    # see https://kubernetes.io/docs/concepts/storage/volumes/#mount-propagation
    # default None
    #
    # WARNING: You very likely do not need this field.
    #
    # This field controls propagation of *additional* mounts created
    # *at runtime* underneath this mount.
    #
    # On MacOS with Docker Desktop, if the mount is from macOS and not the
    # docker desktop VM, you cannot use this field. You can use it for
    # mounts to the linux VM.
    propagation: None

examples/config-with-mounts.yaml
kind: Cluster apiVersion: kind.x-k8s.io/v1alpha4 nodes: - role: control-plane # add a mount from /path/to/my/files on the host to /files on the node extraMounts: - hostPath: /path/to/my/files containerPath: /files # # add an additional mount leveraging all of the config fields # # generally you only need the two fields above ... # - hostPath: /path/to/my/other-files/ containerPath: /other-files # optional: if set, the mount is read-only. # default false readOnly: true # optional: if set, the mount needs SELinux relabeling. # default false selinuxRelabel: false # optional: set propagation mode (None, HostToContainer or Bidirectional) # see https://kubernetes.io/docs/concepts/storage/volumes/#mount-propagation # default None # # WARNING: You very likely do not need this field. # # This field controls propagation of additional mounts created # at runtime underneath this mount. # # On MacOS with Docker Desktop, if the mount is from macOS and not the # docker desktop VM, you cannot use this field. You can use it for # mounts to the linux VM. propagation: None

examples/config-with-mounts.yaml

kind: Cluster
apiVersion: kind.x-k8s.io/v1alpha4
nodes:
- role: control-plane
  # add a mount from /path/to/my/files on the host to /files on the node
  extraMounts:
  - hostPath: /path/to/my/files
    containerPath: /files
  #
  # add an additional mount leveraging *all* of the config fields
  #
  # generally you only need the two fields above ...
  #
  - hostPath: /path/to/my/other-files/
    containerPath: /other-files
    # optional: if set, the mount is read-only.
    # default false
    readOnly: true
    # optional: if set, the mount needs SELinux relabeling.
    # default false
    selinuxRelabel: false
    # optional: set propagation mode (None, HostToContainer or Bidirectional)
    # see https://kubernetes.io/docs/concepts/storage/volumes/#mount-propagation
    # default None
    #
    # WARNING: You very likely do not need this field.
    #
    # This field controls propagation of *additional* mounts created
    # *at runtime* underneath this mount.
    #
    # On MacOS with Docker Desktop, if the mount is from macOS and not the
    # docker desktop VM, you cannot use this field. You can use it for
    # mounts to the linux VM.
    propagation: None

NOTE: If you are using Docker for Mac or Windows check that the hostPath is included in the Preferences -> Resources -> File Sharing.

For more information see the Docker file sharing guide.

Extra Port Mappings 🔗︎

Extra port mappings can be used to port forward to the kind nodes. This is a cross-platform option to get traffic into your kind cluster.

If you are running Docker without the Docker Desktop Application on Linux, you can simply send traffic to the node IPs from the host without extra port mappings. With the installation of the Docker Desktop Application, whether it is on macOs, Windows or Linux, you’ll want to use these.

You may also want to see the Ingress Guide.

examples/config-with-port-mapping.yaml
`kind: Cluster apiVersion: kind.x-k8s.io/v1alpha4 nodes: - role: control-plane # port forward 80 on the host to 80 on this node extraPortMappings: - containerPort: 80 hostPort: 80 # optional: set the bind address on the host # 0.0.0.0 is the current default listenAddress: "127.0.0.1" # optional: set the protocol to one of TCP, UDP, SCTP. # TCP is the default protocol: TCP`

examples/config-with-port-mapping.yaml

kind: Cluster
apiVersion: kind.x-k8s.io/v1alpha4
nodes:
- role: control-plane
  # port forward 80 on the host to 80 on this node
  extraPortMappings:
  - containerPort: 80
    hostPort: 80
    # optional: set the bind address on the host
    # 0.0.0.0 is the current default
    listenAddress: "127.0.0.1"
    # optional: set the protocol to one of TCP, UDP, SCTP.
    # TCP is the default
    protocol: TCP

An example http pod mapping host ports to a container port.


`kind: Pod apiVersion: v1 metadata: name: foo spec: containers: - name: foo image: hashicorp/http-echo:0.2.3 args: - "-text=foo" ports: - containerPort: 5678 hostPort: 80`

NodePort with Port Mappings 🔗︎

To use port mappings with NodePort, the kind node containerPort and the service nodePort needs to be equal.


`kind: Cluster apiVersion: kind.x-k8s.io/v1alpha4 nodes: - role: control-plane extraPortMappings: - containerPort: 30950 hostPort: 80`

And then set nodePort to be 30950.


`kind: Pod apiVersion: v1 metadata: name: foo labels: app: foo spec: containers: - name: foo image: hashicorp/http-echo:0.2.3 args: - "-text=foo" ports: - containerPort: 5678 --- apiVersion: v1 kind: Service metadata: name: foo spec: type: NodePort ports: - name: http nodePort: 30950 port: 5678 selector: app: foo`

kind: Pod
apiVersion: v1
metadata:
  name: foo
  labels:
    app: foo
spec:
  containers:
  - name: foo
    image: hashicorp/http-echo:0.2.3
    args:
    - "-text=foo"
    ports:
    - containerPort: 5678
---
apiVersion: v1
kind: Service
metadata:
  name: foo
spec:
  type: NodePort
  ports:
  - name: http
    nodePort: 30950
    port: 5678
  selector:
    app: foo

Extra Labels 🔗︎

Extra labels might be useful for working with nodeSelectors.

An example label for specifying a tier label:


`kind: Cluster apiVersion: kind.x-k8s.io/v1alpha4 nodes: - role: control-plane - role: worker extraPortMappings: - containerPort: 30950 hostPort: 80 labels: tier: frontend - role: worker labels: tier: backend`

kind: Cluster
apiVersion: kind.x-k8s.io/v1alpha4
nodes:
- role: control-plane
- role: worker
  extraPortMappings:
  - containerPort: 30950
    hostPort: 80
  labels:
    tier: frontend
- role: worker
  labels:
    tier: backend

Kubeadm Config Patches 🔗︎

KIND uses kubeadm to configure cluster nodes.

Formally KIND runs kubeadm init on the first control-plane node, we can customize the flags by using the kubeadm InitConfiguration (spec)


`kind: Cluster apiVersion: kind.x-k8s.io/v1alpha4 nodes: - role: control-plane kubeadmConfigPatches: - \| kind: InitConfiguration nodeRegistration: kubeletExtraArgs: node-labels: "my-label=true"`

If you want to do more customization, there are four configuration types available during kubeadm init: InitConfiguration, ClusterConfiguration, KubeProxyConfiguration, KubeletConfiguration. For example, we could override the apiserver flags by using the kubeadm ClusterConfiguration (spec):


`kind: Cluster apiVersion: kind.x-k8s.io/v1alpha4 nodes: - role: control-plane kubeadmConfigPatches: - \| kind: ClusterConfiguration apiServer: extraArgs: enable-admission-plugins: NodeRestriction,MutatingAdmissionWebhook,ValidatingAdmissionWebhook`

kind: Cluster
apiVersion: kind.x-k8s.io/v1alpha4
nodes:
- role: control-plane
  kubeadmConfigPatches:
  - |
    kind: ClusterConfiguration
    apiServer:
        extraArgs:
          enable-admission-plugins: NodeRestriction,MutatingAdmissionWebhook,ValidatingAdmissionWebhook

On every additional node configured in the KIND cluster, worker or control-plane (in HA mode), KIND runs kubeadm join which can be configured using the JoinConfiguration (spec)


`kind: Cluster apiVersion: kind.x-k8s.io/v1alpha4 nodes: - role: control-plane - role: worker - role: worker kubeadmConfigPatches: - \| kind: JoinConfiguration nodeRegistration: kubeletExtraArgs: node-labels: "my-label2=true" - role: control-plane kubeadmConfigPatches: - \| kind: JoinConfiguration nodeRegistration: kubeletExtraArgs: node-labels: "my-label3=true"`

kind: Cluster
apiVersion: kind.x-k8s.io/v1alpha4
nodes:
- role: control-plane
- role: worker
- role: worker
  kubeadmConfigPatches:
  - |
    kind: JoinConfiguration
    nodeRegistration:
      kubeletExtraArgs:
        node-labels: "my-label2=true"    
- role: control-plane
  kubeadmConfigPatches:
  - |
    kind: JoinConfiguration
    nodeRegistration:
      kubeletExtraArgs:
        node-labels: "my-label3=true"

If you need more control over patching, strategic merge and JSON6092 patches can be used as well. These are specified using files in a directory, for example ./patches/kube-controller-manager.yaml could be the following.


`apiVersion: v1 kind: Pod metadata: name: kube-controller-manager namespace: kube-system spec: containers: - name: kube-controller-manager env: - name: KUBE_CACHE_MUTATION_DETECTOR value: "true"`

Then in your kind YAML configuration use the following.


`nodes: - role: control-plane extraMounts: - hostPath: ./patches containerPath: /patches kubeadmConfigPatches: - \| kind: InitConfiguration patches: directory: /patches`

Note the extraMounts stanza. The node is a container created by kind. kubeadm is run inside this node container, and the local directory that contains the patches has to be accessible to kubeadm. extraMounts plumbs a local directory through to this node container.

This example was for changing the manager in the control plane. To use a patch for a worker node, use a JoinConfiguration patch and an extraMounts stanza for the worker role.