I'm initiating a kubernetes cluster with:
kubeadm init --pod-network-cidr=192.168.1.0/16 --apiserver-advertise-address=192.168.0.33
I'm not too familiar with networking concepts or CIDR, how do I determine an appropriate value for the pod CIDR?
I previously used 10.244.0.0/16
but that resulted in:
Failed create pod sandbox: rpc error: code = Unknown desc = failed to set up sandbox container "78cf556b2e87e15cc5ec8827ca3a397c16dcfb90f045e225a17028f072db6e5f" network for pod "coredns-78fcdf6894-c7kq2": NetworkPlugin cni failed to set up pod "coredns-78fcdf6894-c7kq2_kube-system" network: failed to set bridge addr: "cni0" already has an IP address different from 10.244.1.1/24
Regarding CIDR (Classless Inter-Domain Routing
): That is just a notation to define the subnet / range of IP addresses that you want to use in your network.
If you want to use /16
, you must be planning the creation of a fairly big Kubernetes cluster since that will give you >65k
virtual IP addresses (Note that we are talking about the SDN / Virtual network, i.e., the IPs you will set for your kubernetes PODs, not your actual nodes / hosts). Here is a CIDR table you can use as reference to decide a more suitable range: https://kb.wisc.edu/ns/page.php?id=3493
Now, in terms of your failure that depends on the CNI (Container Networking Interface
) plugin you are using in your Kubernetes cluster. If you are using the default one that must be Kubenet
, which has limitations. More information here: https://kubernetes.io/docs/concepts/extend-kubernetes/compute-storage-net/network-plugins/ and here: https://chrislovecnm.com/kubernetes/cni/choosing-a-cni-provider/
I hope that helps.