Subnets and Pods

Some subnets are reserved by Kubernetes and can prevent proper cluster deployment if you unknowingly configure DKP so that the Node subnet collides with either the Pod or Service subnet.

Ensure your subnets do not overlap with your host subnet because they cannot be changed after cluster creation. If you need to change the Kubernetes subnets, you must do this at cluster creation.

The default subnets used in DKP are:

CODE

spec:
  clusterNetwork:
    pods:
      cidrBlocks:
      - 192.168.0.0/16
    services:
      cidrBlocks:
      - 10.96.0.0/12

If you need to change the Kubernetes subnets, you must do this at cluster creation. To change the subnets, perform the following steps:

Generate the YAML manifests for the cluster using the --dry-run and -o yaml flags, along with the desired dkp cluster create command:

CODE

dkp create cluster preprovisioned --cluster-name ${CLUSTER_NAME} --control-plane-endpoint-host <control plane endpoint host> --control-plane-endpoint-port <control plane endpoint port, if different than 6443> --dry-run -o yaml > cluster.yaml

MetalLB IP address ranges/CIDRs and node subnet should not conflict with the Kubernetes cluster pod and service subnets.

To modify the service subnet, add or edit the spec.clusterNetwork.services.cidrBlocks field of the Cluster object:
CODE
```
kind: Cluster
spec:
  clusterNetwork:
    services:
      cidrBlocks:
      - 10.0.0.0/12
```

To modify the pod subnet, edit the Cluster and calico-cni ConfigMap resources:

Cluster: Add or edit thespec.clusterNetwork.pods.cidrBlocks field:

CODE

kind: Cluster
spec:
  clusterNetwork:
    pods:
      cidrBlocks:
      - 172.16.0.0/16

ConfigMap: Edit the data."custom-resources.yaml".spec.calicoNetwork.ipPools.cidr field with your desired pod subnet:

CODE

apiVersion: v1
data:
  custom-resources.yaml: |
    apiVersion: operator.tigera.io/v1
    kind: Installation
    metadata:
      name: default
    spec:
      # Configures Calico networking.
      calicoNetwork:
        # Note: The ipPools section cannot be modified post-install.
        ipPools:
        - blockSize: 26
          cidr: 172.16.0.0/16
kind: ConfigMap
metadata:
  name: calico-cni-<cluter-name>

When you provision the cluster, the configured pod and service subnets will be applied.

Next Steps

Proceed to installation instructions:

If using the Custom Installation and Additional Infrastructure Tools instructions, proceed to the infrastructure provider you are using.
If using the Day 1 - Basic Installs by Infrastructure instructions, proceed (or return) to that section to install and setup DKP based on your infrastructure environment provider.

Related Topics

Next Steps