I initialize a 5 node k8s cluster as below:
[root@lpdkubpoc01a ~]# kubeadm init --pod-network-cidr=10.96.0.0/16 --service-cidr=10.97.0.0/16 --image-repository quaytest.phx.aexp.com/control-plane
W0727 15:19:51.123991 1866 version.go:101] could not fetch a Kubernetes version from the internet: unable to get URL "https://dl.k8s.io/release/stable-1.txt": Get https://dl.k8s.io/release/stable-1.txt: dial tcp: lookup dl.k8s.io on 10.2.88.196:53: no such host
W0727 15:19:51.124080 1866 version.go:102] falling back to the local client version: v1.17.5
W0727 15:19:51.124236 1866 validation.go:28] Cannot validate kube-proxy config - no validator is available
W0727 15:19:51.124244 1866 validation.go:28] Cannot validate kubelet config - no validator is available
[init] Using Kubernetes version: v1.17.5
[preflight] Running pre-flight checks
...
...
Your Kubernetes control-plane has initialized successfully!
To start using your cluster, you need to run the following as a regular user:
```bash
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/configYou 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 10.22.76.244:6443 --token fa5ia8.oqs7jv9ii6wzex0w \
--discovery-token-ca-cert-hash sha256:6680c99e6c49e0dce4522bc9768bfc2e7e2b38f5a10668d3a544554ab0d09ff1
I run the below, per the above instructions:
[root@lpdkubpoc01a ~]# mkdir -p $HOME/.kube
[root@lpdkubpoc01a ~]# cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
cp: overwrite ‘/root/.kube/config’? y
[root@lpdkubpoc01a ~]# chown $(id -u):$(id -g) $HOME/.kube/configBut when I check the control plane component pods, I see them all initialized with 1) same IP address 2) incorrect CIDR => seems to be in the host network which is a big NO-NO
```bash
[root@lpdkubpoc01a ~]# kubectl get pods -n kube-system -owide
NAME READY STATUS
RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
coredns-598947db54-dzrjk 0/1 Pending 0 37s <none> <none> <none> <none>
coredns-598947db54-t2wch 0/1 Pending 0 37s <none> <none> <none> <none>
etcd-lpdkubpoc01a.phx.aexp.com 1/1 Running 0 50s 10.22.76.244 lpdkubpoc01a.phx.aexp.com <none> <none>
kube-apiserver-lpdkubpoc01a.phx.aexp.com 1/1 Running 0 50s 10.22.76.244 lpdkubpoc01a.phx.aexp.com <none> <none>
kube-controller-manager-lpdkubpoc01a.phx.aexp.com 1/1 Running 0 50s 10.22.76.244 lpdkubpoc01a.phx.aexp.com <none> <none>
kube-proxy-8dbx2 1/1 Running 0 38s 10.22.76.244 lpdkubpoc01a.phx.aexp.com <none> <none>
kube-scheduler-lpdkubpoc01a.phx.aexp.com 1/1 Running 0 50s 10.22.76.244 lpdkubpoc01a.phx.aexp.com <none> <none>
```
What is wrong and how do I remedy it? The pods in the kube-system ns should not have the same IP and definitely not in the same network as the host:
[root@lpdkubpoc01a ~]# ifconfig
docker0: flags=4099<UP,BROADCAST,MULTICAST> mtu 1500
inet 172.17.0.1 netmask 255.255.0.0 broadcast 0.0.0.0
ether 02:42:40:17:25:e4 txqueuelen 0 (Ethernet)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
**eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 10.22.76.244 netmask 255.255.254.0 broadcast 10.22.77.255
ether 00:50:56:b8:e1:84 txqueuelen 1000 (Ethernet)
RX packets 73810789 bytes 8755922965 (8.1 GiB)
RX errors 0 dropped 31388 overruns 0 frame 0
TX packets 44487774 bytes 12389932340 (11.5 GiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0**
eth1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 9000
inet 10.0.195.100 netmask 255.255.254.0 broadcast 10.0.195.255
ether 00:50:56:b8:6c:23 txqueuelen 1000 (Ethernet)
RX packets 3573616 bytes 708218742 (675.4 MiB)
RX errors 0 dropped 50118 overruns 0 frame 0
TX packets 830522 bytes 174979700 (166.8 MiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
loop txqueuelen 1000 (Local Loopback)
RX packets 263222455 bytes 44942504690 (41.8 GiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 263222455 bytes 44942504690 (41.8 GiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
Thanks!
control plane components are statics pods, you can see their yaml files in /etc/kubernetes/manifest/ directory and kubelete of the master node is responsible for checking them to be running. So it is normal for static pods to have their local host's IP.
By the way you still need a kubernetes network addons like Calico or Weave net. check this link.<br> https://kubernetes.io/docs/concepts/cluster-administration/addons/ <br> For example in your case, you just need to run this command to deploy weave net addons with your desire pod-network-cidr: <br><br>
kubectl apply -f "https://cloud.weave.works/k8s/net?k8s-version=$(kubectl version | base64 | tr -d '\n')&env.IPALLOC_RANGE=10.96.0.0/16" <br><br> Be careful to specify your pod-network-cidr when deploy network addons.
its normal for the controlplane pods to have node ip's. everything else will get ip's from the cni.
It doesn't even look like your pod network has been configured. You can install something like Calico or Weave. Your coredns pods should come up after that and also your other pods should get different IP addresses.
In the past, these instructions were on the main kubeadm page, but it's my understanding that they have actually been deprecated in favor of standardizing more on CNI and letting each of one the CNI providers provide their own installation instructions.
✌️