kubernetes - Couldn't able to join master node - error execution phase preflight: couldn't validate the identity of the API Server

Here are mistakes which realized i did during my kubernetes installation -

(For detailed installation step follow - Steps for Installation )

But here are the key mistakes which i did -

Mistake 1 - Since i was working on the VMs so i had multiple ethernet adapter on my both the VMs (master as well as worker ). By default the the CNI always takes the eth0 but i our case it should be eth1

1: lo: <LOOPBACK,UP,LOWER_UP>
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether 08:00:27:bb:14:75 brd ff:ff:ff:ff:ff:ff
    inet 10.0.2.15
3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether 08:00:27:fb:48:77 brd ff:ff:ff:ff:ff:ff
    inet 100.0.0.1
4: docker0: <NO-CARRIER,BROADCAST,MULTICAST,UP>

Mistake 2- The way i was initializing the my kubeadm without --apiserver-advertise-address and --pod-network-cidr

So here is kubeadm command which i used -

[vagrant@master ~]$ sudo kubeadm init --apiserver-advertise-address=100.0.0.1 --pod-network-cidr=10.244.0.0/16

Mistake 3 - - Since we have mulitple ethernet adapter in our VMs so i coudln't find the a way to set up extra args to switch from eth0 to eth1 in calico.yml configuration.

So i used flannel CNI*

[vagrant@master ~]$ wget https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml

and in the args section added - --iface=eth1

- --iface=eth1
        args:
        - --ip-masq
        - --kube-subnet-mgr
        - --iface=eth1

And it worked after that

It worked for me using this --apiserver-advertise-address:

sudo kubeadm init --apiserver-advertise-address=172.16.28.10 --pod-network-cidr=192.168.0.0/16

kubectl apply -f https://docs.projectcalico.org/v3.8/manifests/calico.yaml

I have used calico and worked for me.

In Member node for join:

kubeadm join 172.16.28.10:6443 --token 2jm9hd.o2gulx4x1b8l1t5d \ --discovery-token-ca-cert-hash sha256:b8b679e86c4d228bfa486086f18dcac4760e5871e8dd023ec166acfd93781595