Kubernetes : Configure Master Node2020/08/19 |
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Install Kubeadm to Configure Multi Nodes Kubernetes Cluster.
This example is based on the emvironment like follows.
-----------+---------------------------+--------------------------+------------
| | |
eth0|10.0.0.30 eth0|10.0.0.51 eth0|10.0.0.52
+----------+-----------+ +-----------+----------+ +-----------+----------+
| [ dlp.srv.world ] | | [ node01.srv.world ] | | [ node02.srv.world ] |
| Master Node | | Worker Node | | Worker Node |
+----------------------+ +----------------------+ +----------------------+
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| [1] |
| [2] |
Configure initial setup on Master Node.
For [--apiserver-advertise-address] option, specify the IP address Kubernetes API server listens.
For [--pod-network-cidr] option, specify network which Pod Network uses.
There are some plugins for Pod Network. (refer to details below)
⇒ https://kubernetes.io/docs/concepts/cluster-administration/networking/
On this example, select Flannel. For Flannel, specify [--pod-network-cidr=10.244.0.0/16] to let Pod Network work normally.
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root@dlp:~# kubeadm init --apiserver-advertise-address=10.0.0.30 --pod-network-cidr=10.244.0.0/16
W0818 14:18:23.411218 5697 configset.go:202] WARNING: kubeadm cannot validate component configs for API groups [kubelet.config.k8s.io kubeproxy.config.k8s.io]
[init] Using Kubernetes version: v1.18.8
[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'
[kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env"
[kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml"
[kubelet-start] Starting the kubelet
.....
.....
[kubelet-finalize] Updating "/etc/kubernetes/kubelet.conf" to point to a rotatable kubelet client certificate and key
[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:
# the command below is necessary to run on Worker Node when he joins to the cluster, so remember it
kubeadm join 10.0.0.30:6443 --token 2ai7nw.g02n51jp4ak0i63j \
--discovery-token-ca-cert-hash sha256:19d10da61c574672cb292f33c56d246da8615d29bbf9cbf2d7152140caa27e8b
# set cluster admin user # if you set common user as cluster admin, login with it and run [sudo cp/chown ***] root@dlp:~# mkdir -p $HOME/.kube root@dlp:~# cp -i /etc/kubernetes/admin.conf $HOME/.kube/config root@dlp:~# chown $(id -u):$(id -g) $HOME/.kube/config
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| [3] | Configure Pod Network with Flannel. |
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root@dlp:~# kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml podsecuritypolicy.policy/psp.flannel.unprivileged created clusterrole.rbac.authorization.k8s.io/flannel created clusterrolebinding.rbac.authorization.k8s.io/flannel created serviceaccount/flannel created configmap/kube-flannel-cfg created daemonset.apps/kube-flannel-ds-amd64 created daemonset.apps/kube-flannel-ds-arm64 created daemonset.apps/kube-flannel-ds-arm created daemonset.apps/kube-flannel-ds-ppc64le created daemonset.apps/kube-flannel-ds-s390x created # show state ⇒ OK if STATUS = Ready root@dlp:~# kubectl get nodes NAME STATUS ROLES AGE VERSION dlp.srv.world Ready master 7m7s v1.18.8 # show state ⇒ OK if all are Running root@dlp:~# kubectl get pods -A NAMESPACE NAME READY STATUS RESTARTS AGE kube-system coredns-66bff467f8-968bw 1/1 Running 0 7m47s kube-system coredns-66bff467f8-xd2m7 1/1 Running 0 7m47s kube-system etcd-dlp.srv.world 1/1 Running 0 7m56s kube-system kube-apiserver-dlp.srv.world 1/1 Running 0 7m55s kube-system kube-controller-manager-dlp.srv.world 1/1 Running 0 7m56s kube-system kube-flannel-ds-amd64-k8fbp 1/1 Running 0 85s kube-system kube-proxy-h588r 1/1 Running 0 7m47s kube-system kube-scheduler-dlp.srv.world 1/1 Running 0 7m56s |
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