kubectl proxy not working on Ubuntu LTS 18.04

I noticed that the guide You used to install kubernetes cluster is missing one important part.

According to kubernetes documentation:

For flannel to work correctly, you must pass --pod-network-cidr=10.244.0.0/16 to kubeadm init.

Set /proc/sys/net/bridge/bridge-nf-call-iptables to 1 by running sysctl net.bridge.bridge-nf-call-iptables=1 to pass bridged IPv4 traffic to iptables’ chains. This is a requirement for some CNI plugins to work, for more information please see here.

Make sure that your firewall rules allow UDP ports 8285 and 8472 traffic for all hosts participating in the overlay network. see here .

Note that flannel works on amd64, arm, arm64, ppc64le and s390x under Linux. Windows (amd64) is claimed as supported in v0.11.0 but the usage is undocumented.

kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/2140ac876ef134e0ed5af15c65e414cf26827915/Documentation/kube-flannel.yml

For more information about flannel, see the CoreOS flannel repository on GitHub .

To fix this:

I suggest using the command:

sysctl net.bridge.bridge-nf-call-iptables=1

And then reinstall flannel:

kubectl delete -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml

kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml

Update: After verifying the the /proc/sys/net/bridge/bridge-nf-call-iptables value is 1 by default ubuntu-18-04-lts. So issue here is You need to access the dashboard locally.

If You are connected to Your master node via ssh. It could be possible to use -X flag with ssh in order to launch we browser via ForwardX11. Fortunately ubuntu-18-04-lts has it turned on by default.

ssh -X server

Then install local web browser like chromium.

sudo apt-get install chromium-browser

chromium-browser

And finally access the dashboard locally from node.

http://localhost:8001/api/v1/namespaces/kubernetes-dashboard/services/https:kubernetes-dashboard:/proxy/

Hope it helps.