Cannot initialize Kubernetes cluster on Ubuntu 18.04 (Virtual Box) - docker

Question

I struggle to initialize a simple Kubernetes cluster using Ubuntu on Virtualbox. I tried both server and desktop version, following the official documentation:
https://kubernetes.io/docs/setup/production-environment/container-runtimes/#docker
https://kubernetes.io/docs/setup/production-environment/tools/kubeadm/install-kubeadm/
https://kubernetes.io/docs/setup/production-environment/tools/kubeadm/create-cluster-kubeadm/
I also tried to follow some other ones, thinking the issue was because i'm using Virtualbox VM's, like this one:
https://medium.com/#gunjangarge/create-kubernetes-cluster-using-kubeadm-on-ubuntu-virtualbox-step-by-step-68a3eeb1f74c
But everytime I have the same issue with port 6443 not being exposed. Sometimes the process starts correctly, giving me the join command:
kubeadm init --pod-network-cidr=192.168.0.0/16
W1029 08:47:53.841460 11540 configset.go:348] WARNING: kubeadm cannot validate component configs
for API groups [kubelet.config.k8s.io kubeproxy.config.k8s.io]
[init] Using Kubernetes version: v1.19.3
[preflight] Running pre-flight checks
[preflight] Pulling images required for setting up a Kubernetes cluster
[preflight] This might take a minute or two, depending on the speed of your internet connection
[preflight] You can also perform this action in beforehand using 'kubeadm config images pull'
[certs] Using certificateDir folder "/etc/kubernetes/pki"
[addons] Applied essential addon: CoreDNS
[addons] Applied essential addon: kube-proxy
Your Kubernetes control-plane has initialized successfully!
To start using your cluster, you need to run the following as a regular user:
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config
You should now deploy a pod network to the cluster.
Run "kubectl apply -f [podnetwork].yaml" with one of the options listed at:
https://kubernetes.io/docs/concepts/cluster-administration/addons/
Then you can join any number of worker nodes by running the following on each as root:
kubeadm join 192.168.1.192:6443 --token ztnoww.t8ng5a3jo2kx5cb2 \
--discovery-token-ca-cert-hash
sha256:907dde6cc6d72ed4cd7fe7e7f252e2cf657dd3256fba6ee5ec92027132a9c5af
Sometimes it's not starting at all and timeouting:
[wait-control-plane] Waiting for the kubelet to boot up the control plane as static Pods from directory "/etc/kubernetes/manifests". This can take up to 4m0s
[kubelet-check] Initial timeout of 40s passed.
Unfortunately, an error has occurred:
timed out waiting for the condition
This error is likely caused by:
- The kubelet is not running
- The kubelet is unhealthy due to a misconfiguration of the node in some way (required cgroups disabled)
If you are on a systemd-powered system, you can try to troubleshoot the error with the following commands:
- 'systemctl status kubelet'
- 'journalctl -xeu kubelet'
Additionally, a control plane component may have crashed or exited when started by the container runtime.
To troubleshoot, list all containers using your preferred container runtimes CLI.
Here is one example how you may list all Kubernetes containers running in docker:
- 'docker ps -a | grep kube | grep -v pause'
Once you have found the failing container, you can inspect its logs with:
- 'docker logs CONTAINERID'
error execution phase wait-control-plane: couldn't initialize a Kubernetes cluster
To see the stack trace of this error execute with --v=5 or higher
Anyway, even when it's starting, port 6443 is never exposed, and kubelet is not happy with it:
kubelet.service - kubelet: The Kubernetes Node Agent
Loaded: loaded (/lib/systemd/system/kubelet.service; enabled; vendor preset: enabled)
Drop-In: /etc/systemd/system/kubelet.service.d
└─10-kubeadm.conf
Active: active (running) since Thu 2020-10-29 08:48:15 CET; 20s ago
Docs: https://kubernetes.io/docs/home/
Main PID: 13262 (kubelet)
Tasks: 14 (limit: 4666)
CGroup: /system.slice/kubelet.service
└─13262 /usr/bin/kubelet --bootstrap-kubeconfig=/etc/kubernetes/bootstrap-kubelet.conf --kubeconfig=/etc/kubernetes/kubelet.conf --config=/var/lib/kubelet/config.yaml --network-plugin=cni --pod-infra-contai
Okt 29 08:48:22 master kubelet[13262]: E1029 08:48:22.588386 13262 controller.go:136] failed to ensure node lease exists, will retry in 800ms, error: Get
"https://192.168.1.192:6443/apis/coordination.k8s.io/v1/names
Okt 29 08:48:22 master kubelet[13262]: E1029 08:48:22.785951 13262 reflector.go:127] k8s.io/client-go/informers/factory.go:134: Failed to watch *v1.Service: failed to list *v1.Service: Get "https://192.168.1.192:644
Okt 29 08:48:23 master kubelet[13262]: I1029 08:48:23.022354 13262 kubelet_node_status.go:70] Attempting to register node master
Okt 29 08:48:24 master kubelet[13262]: I1029 08:48:24.188510 13262 request.go:645] Throttling request took 1.097264312s, request: POST:https://192.168.1.192:6443/api/v1/namespaces/kube-system/pods
Okt 29 08:48:25 master kubelet[13262]: I1029 08:48:25.678880 13262 kubelet_node_status.go:108] Node master was previously registered
Okt 29 08:48:25 master kubelet[13262]: I1029 08:48:25.679004 13262 kubelet_node_status.go:73] Successfully registered node master
Okt 29 08:48:25 master kubelet[13262]: W1029 08:48:25.765981 13262 cni.go:239] Unable to update cni config: no networks found in /etc/cni/net.d
Okt 29 08:48:27 master kubelet[13262]: E1029 08:48:27.148246 13262 kubelet.go:2103] Container runtime network not ready: NetworkReady=false reason:NetworkPluginNotReady message:docker: network plugin is not ready: c
Okt 29 08:48:30 master kubelet[13262]: W1029 08:48:30.767511 13262 cni.go:239] Unable to update cni config: no networks found in /etc/cni/net.d
Okt 29 08:48:32 master kubelet[13262]: E1029 08:48:32.164211 13262 kubelet.go:2103] Container runtime network not ready: NetworkReady=false reason:NetworkPluginNotReady message:docker: network plugin is not ready: c
I have to say I don't know what to do now. I tried for hours with different Ubuntu versions, trying to find solutions on the Internet but I didn't found any solution. I also went trough the logs and found that maybe the config file is not created correctly for any reason:
failed to load Kubelet config file /var/lib/kubelet/config.yaml, error failed to read kubelet config file "/var/lib/kubelet/config.yaml
but I found nothing about it, except "try to init the cluster again", which I did several times..
Thank you in advance for your help!

Answer 1

OK, I think I finally found the problem. I tried the same process on another PC and everything worked smoothly, so for anyway of you having a similar issue, just don't try to use VirtualBox and WSL at the same time (even if wsl is shut off)
I just did what's explained here: https://stackoverflow.com/a/63229718/2428805 and now everything's fine...