podCIDR error when creating Flannel network

Hi,
I'm creating a cluster using Kelsey Hightowers "Kubernetes the hard way", with some customization. I'm doing it locally using KVM, for instance. Also not HA. I intend it to be 1 cp master and 2 worker nodes.
I'm using this manifest for Flannel:
https://raw.githubusercontent.com/flannel-io/flannel/master/Documentation/kube-flannel.yml
I've provisioned a CP master and a worker node. When I create the Flannel overlay network I get an error about podCIDR and the flannel ds does not come up.
Running: kubectl -n kube-flannel logs kube-flannel-ds-ws8lj
I get:
Error registering network: failed to acquire lease: node "c2-worker1" pod cidr not assigned
Because it's a cluster, I'm not configuring podCIDR in kubelet on the worker node:
--pod-cidr string The CIDR to use for pod IP addresses, only used in standalone mode. In cluster mode, this is obtained from the master.
https://kubernetes.io/docs/reference/command-line-tools-reference/kubelet/
I can manually add podCIDR to the node applying a patch:kubectl patch nodes c2-worker1 --patch '{"spec": {"podCIDR":"10.244.0.0/16"}}'
Then, Flannel overlay network comes up as expected.
What's happening here?
Best Answer
-
I solved it.
I needed to pass
--allocate-node-cidrs=true
to the kube-controller-manager.I'm running it as a systemd service. The start of the unit file looks like this:
[Service] ExecStart=/usr/bin/kube-controller-manager \ --cluster-cidr=10.244.0.0/16 \ --allocate-node-cidrs=true \
Now each node is assigned a /24 each and it works as expected without a manual patch.
kubectl describe nodes | grep -i cidr
PodCIDR: 10.244.0.0/24 PodCIDRs: 10.244.0.0/24 PodCIDR: 10.244.1.0/24 PodCIDRs: 10.244.1.0/24
0
Answers
-
can you please mention file name to edit
0
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