CUSTOM_MGMT_NETWORK.md

Setting up a custom management network on multi-homed nodes

If the interface you use for Kubernetes management traffic (for example, the IP address used for kubeadm join) is not the one that contains the default route out of the host, you need to specify the management node IP address in the Kubelet config file. Add/update the following line in /etc/default/kubelet (or /etc/systemd/system/kubelet.service.d/10-kubeadm.conf for versions below 1.11):

KUBELET_EXTRA_ARGS=--fail-swap-on=false --node-ip=<node-management-ip-address>

Example:

Consider a 2 node deployment where each node is connected to 2 networks - 10.0.2.0/24 and 192.168.56.0/24, and the default route on each node points to the interface connected to the 10.0.2.0/24 subnet. We want to use subnet 192.168.56.0/24 for Kubernetes management traffic. Assume the addresses of nodes connected to 192.168.56.0/24 are 192.168.56.105 and 192.168.56.106.

On the 192.168.56.105 node you add the following line to the kubelet config file:

KUBELET_EXTRA_ARGS=--fail-swap-on=false --node-ip=192.168.56.105

On the 192.168.56.106 node you add the following line to the kubelet config file:

KUBELET_EXTRA_ARGS=--fail-swap-on=false --node-ip=192.168.56.106