I have a single master cluster with 3 worker nodes. The master node has one network interface of 10Gb capacity and all worker nodes have two interfaces: 10Gb and 40Gb interface. They are all connected via a switch.
By default, Kubernetes binds to the default network eth0 which is 10Gb for the worker nodes. How do I specify the 40Gb interface at joining?
The kubeadm init command has a --apiserver-advertise-address argument but this is for the apiserver. Is there any equivalent option for the worker nodes so the communciation between master and worker (and between workers) are realised on the 40Gb link?
Please note that this is a bare-metal on-prem installation with OSS Kubernetes v1.20.
There is nothing specific, you would have to manage this at the routing level. If you're using BGP internally it would usually do this automatically because the faster link will have a higher metric but if you're using a simpler static routing setup then you may need to tweak things.
Pods live on internal virtual adapters so they don't listen on any physical interface (for all CNIs I know of anyway, except the AWS one).
You can use the --hostname-override flag to override the default kubelet behavior. The default name of the kubelet equals to the hostname and it's ip address default to the interface's ip address default gateway.
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