使用kubeadm安装kubernetes集群

安装kubeadm

参考官方：https://kubernetes.io/docs/setup/independent/create-cluster-kubeadm/

安装之前

Ubuntu 16.04+, CentOS 7 or HypriotOS v1.0.1+
1GB 以上内存
良好的网络环境
每个节点的唯一的MAC和product_uuid
确保用到的端口可用

安装Docker

https://docs.docker.com/engine/installation/

安装kubectl

https://kubernetes.io/docs/tasks/tools/install-kubectl/

安装kubelet和kubeadm

ubuntu:

apt-get update && apt-get install -y apt-transport-https
curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | apt-key add -
cat <<EOF >/etc/apt/sources.list.d/kubernetes.list
deb http://apt.kubernetes.io/ kubernetes-xenial main
EOF
apt-get update
apt-get install -y kubelet kubeadm

用kubeadm创建kubernetes集群

初始化master

master是各组件的控制中心，包括etcd，API server（kubectl CLI）

kubeadm init --pod-network-cidr=10.244.0.0/16

--pod-network-cidr=10.244.0.0/16为后面的Flannel配置
成功后大致如下：

[kubeadm] WARNING: kubeadm is in beta, please do not use it for production clusters.
[init] Using Kubernetes version: v1.7.0
[init] Using Authorization modes: [Node RBAC]
[preflight] Running pre-flight checks
[preflight] Starting the kubelet service
[certificates] Generated CA certificate and key.
[certificates] Generated API server certificate and key.
[certificates] API Server serving cert is signed for DNS names [kubeadm-master kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local] and IPs [10.96.0.1 10.138.0.4]
[certificates] Generated API server kubelet client certificate and key.
[certificates] Generated service account token signing key and public key.
[certificates] Generated front-proxy CA certificate and key.
[certificates] Generated front-proxy client certificate and key.
[certificates] Valid certificates and keys now exist in "/etc/kubernetes/pki"
[kubeconfig] Wrote KubeConfig file to disk: "/etc/kubernetes/admin.conf"
[kubeconfig] Wrote KubeConfig file to disk: "/etc/kubernetes/kubelet.conf"
[kubeconfig] Wrote KubeConfig file to disk: "/etc/kubernetes/controller-manager.conf"
[kubeconfig] Wrote KubeConfig file to disk: "/etc/kubernetes/scheduler.conf"
[apiclient] Created API client, waiting for the control plane to become ready
[apiclient] All control plane components are healthy after 16.502136 seconds
[token] Using token: <token>
[apiconfig] Created RBAC rules
[addons] Applied essential addon: kube-proxy
[addons] Applied essential addon: kube-dns

Your Kubernetes master has initialized successfully!

To start using your cluster, you need to run (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:
 http://kubernetes.io/docs/admin/addons/

You can now join any number of machines by running the following on each node
as root:

 kubeadm join --token <token> <master-ip>:<master-port>

安装pod network：Flannel

除了Flannel还可以选择Calico、Canal等
安装pod network add-on

kubectl apply -f <add-on.yaml>

确保--pod-network-cidr=10.244.0.0/16在kubeadm init时传入。

kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel-rbac.yml

Master Isolation

kubectl taint nodes --all node-role.kubernetes.io/master-

添加节点

保证ssh可等可登录每台机器

kubeadm join --token <token> <master-ip>:<master-port>

kubeadm join：将子节点加到kubernetes集群中，
token生成方法: https://kubernetes.io/docs/admin/kubeadm/#manage-tokens
输出

[kubeadm] WARNING: kubeadm is in beta, please do not use it for production clusters.
[preflight] Running pre-flight checks
[discovery] Trying to connect to API Server "10.138.0.4:6443"
[discovery] Created cluster-info discovery client, requesting info from "https://10.138.0.4:6443"
[discovery] Cluster info signature and contents are valid, will use API Server "https://10.138.0.4:6443"
[discovery] Successfully established connection with API Server "10.138.0.4:6443"
[bootstrap] Detected server version: v1.7.0
[bootstrap] The server supports the Certificates API (certificates.k8s.io/v1beta1)
[csr] Created API client to obtain unique certificate for this node, generating keys and certificate signing request
[csr] Received signed certificate from the API server, generating KubeConfig...
[kubeconfig] Wrote KubeConfig file to disk: "/etc/kubernetes/kubelet.conf"

Node join complete:
* Certificate signing request sent to master and response
  received.
* Kubelet informed of new secure connection details.

Run 'kubectl get nodes' on the master to see this machine join.

master上检查

kubectl get nodes

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