Kubernetes : Kubeadm : Configure Master Node2019/08/26 |
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Install Kubeadm to Configure Multi Nodes Kubernetes Cluster.
On this example, Configure This example is based on the emvironment like follows.
For System requirements, each Node has uniq Hostname, MAC address, Product_uuid.
MAC address and Product_uuid are generally already uniq one if you installed OS on phisical machine or virtual machine with common procedure. You can see Product_uuid with the command [dmidecode -s system-uuid].
-----------+---------------------------+--------------------------+------------
| | |
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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Configure Master Node on this section.
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| [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
[init] Using Kubernetes version: v1.15.3
[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'
[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] Activating the kubelet service
.....
.....
[bootstrap-token] Creating the "cluster-info" ConfigMap in the "kube-public" namespace
[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 uw8h1x.4vjex3g6tfgt4w2t \
--discovery-token-ca-cert-hash sha256:99c192dcb2b38438c4aacc5029b86447f18f2b93a0fe0fa7a779192bc952fb53
# 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 3m2s v1.15.3 # show state (OK if all are Running) root@dlp:~# kubectl get pods --all-namespaces NAMESPACE NAME READY STATUS RESTARTS AGE kube-system coredns-5c98db65d4-46w67 1/1 Running 0 2m56s kube-system coredns-5c98db65d4-klfb2 1/1 Running 0 2m56s kube-system etcd-dlp.srv.world 1/1 Running 0 116s kube-system kube-apiserver-dlp.srv.world 1/1 Running 0 115s kube-system kube-controller-manager-dlp.srv.world 1/1 Running 0 2m8s kube-system kube-flannel-ds-amd64-pgf88 1/1 Running 0 30s kube-system kube-proxy-zd77s 1/1 Running 0 2m57s kube-system kube-scheduler-dlp.srv.world 1/1 Running 0 2m3s |
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