kubeadm是官方社区推出的一个用于快速部署kubernetes集群的工具。
这个工具能通过两条指令完成一个kubernetes集群的部署：
# 创建一个 Master 节点 $ kubeadm init # 将一个 Node 节点加入到当前集群中 $ kubeadm join <Master节点的IP和端口 >在开始之前，部署Kubernetes集群机器需要满足以下几个条件：
一台或多台机器，操作系统 CentOS7.x-86_x64硬件配置：2GB或更多RAM，2个CPU或更多CPU，硬盘30GB或更多集群中所有机器之间网络互通可以访问外网，需要拉取镜像禁止swap分区Kubernetes默认CRI（容器运行时）为Docker，因此先安装Docker。
1、 安装Docker
wget https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo -O /etc/yum.repos.d/docker-ce.repo yum -y install docker-ce-18.06.1.ce-3.el7 systemctl enable docker && systemctl start docker docker --version Docker version 18.06.1-ce, build e68fc7a cat > /etc/docker/daemon.json << EOF { "registry-mirrors": ["https://b9pmyelo.mirror.aliyuncs.com"] } EOF2、 添加阿里云YUM软件源
cat > /etc/yum.repos.d/kubernetes.repo << EOF [kubernetes] name=Kubernetes baseurl=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64 enabled=1 gpgcheck=0 repo_gpgcheck=0 gpgkey=https://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg https://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg EOF3、 安装kubeadm，kubelet和kubectl
由于版本更新频繁，这里指定版本号部署：
yum install -y kubelet-1.17.0 kubeadm-1.17.0 kubectl-1.17.0 systemctl enable kubelet在192.168.100.110（Master）执行。
kubeadm init \ --apiserver-advertise-address=192.168.100.110 \ --image-repository registry.aliyuncs.com/google_containers \ --kubernetes-version v1.17.0 \ --service-cidr=10.96.0.0/12 \ --pod-network-cidr=10.244.0.0/16由于默认拉取镜像地址k8s.gcr.io国内无法访问，这里指定阿里云镜像仓库地址。
使用kubectl工具：
mkdir -p $HOME/.kube sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config sudo chown $(id -u):$(id -g) $HOME/.kube/config $ kubectl get nodes kubeadm join 192.168.100.110:6443 --token xgpcw7.3zs316i6ui059k7n \ --discovery-token-ca-cert-hash sha256:d188cc0e38044a6e262120c3000658db0ae9db7ff4d858367761d698bc798b9e #以下是成功加入群集的信息 This node has joined the cluster: * Certificate signing request was sent to apiserver and a response was received. * The Kubelet was informed of the new secure connection details. Run 'kubectl get nodes' on the control-plane to see this node join the cluster. [root@k8s-master ~]# kubectl get nodes NAME STATUS ROLES AGE VERSION k8s-master NotReady master 36m v1.17.0 k8s-node1 NotReady <none> 2m59s v1.17.0 k8s-node2 NotReady <none> 2m34s v1.17.0 [root@k8s-master ~]# tail /var/log/messages -f [2183] Container runtime network not ready: NetworkReady=false reason:NetworkPluginNotReady message:docker: network plugin is not ready: cni config uninitialized 下面部署网络确保能够访问到quay.io这个registery。
如果Pod镜像下载失败，可以改成这个镜像地址：lizhenliang/flannel:v0.11.0-amd64
在192.168.100.120/130（Node）执行。
向集群添加新节点，执行在kubeadm init输出的kubeadm join命令：
kubeadm join 192.168.100.110:6443 --token xgpcw7.3zs316i6ui059k7n \ --discovery-token-ca-cert-hash sha256:d188cc0e38044a6e262120c3000658db0ae9db7ff4d858367761d698bc798b9e [root@k8s-master ~]# kubectl get nodes NAME STATUS ROLES AGE VERSION k8s-master Ready master 45m v1.17.0 k8s-node1 Ready <none> 12m v1.17.0 k8s-node2 Ready <none> 12m v1.17.0 [root@k8s-master ~]# kubectl get pods -n kube-system NAME READY STATUS RESTARTS AGE coredns-9d85f5447-f7n8g 1/1 Running 0 48m coredns-9d85f5447-nnwp5 1/1 Running 0 48m etcd-k8s-master 1/1 Running 0 48m kube-apiserver-k8s-master 1/1 Running 0 48m kube-controller-manager-k8s-master 1/1 Running 0 48m kube-flannel-ds-amd64-pdtk5 1/1 Running 0 6m kube-flannel-ds-amd64-sj8tr 1/1 Running 0 6m kube-flannel-ds-amd64-zld2s 1/1 Running 0 6m kube-proxy-dlh5f 1/1 Running 0 15m kube-proxy-z6bqn 1/1 Running 0 15m kube-proxy-zppgq 1/1 Running 0 48m kube-scheduler-k8s-master 1/1 Running 0 48m -n 指定命名空间 默认token有效期为24小时，当过期之后，该token就不可用了。这时就需要重新创建token，操作如下： # kubeadm token create # kubeadm token list # openssl x509 -pubkey -in /etc/kubernetes/pki/ca.crt | openssl rsa -pubin -outform der 2>/dev/null | openssl dgst -sha256 -hex | sed 's/^.* //' 63bca849e0e01691ae14eab449570284f0c3ddeea590f8da988c07fe2729e924 # kubeadm join 192.168.100.110:6443 --token nuja6n.o3jrhsffiqs9swnu --discovery-token-ca-cert-hash sha256:63bca849e0e01691ae14eab449570284f0c3ddeea590f8da988c07fe2729e924kubeadm token create --print-join-command
https://kubernetes.io/docs/reference/setup-tools/kubeadm/kubeadm-join/
在Kubernetes集群中创建一个pod，验证是否正常运行：
$ kubectl create deployment nginx --image=nginx $ kubectl expose deployment nginx --port=80 --type=NodePort $ kubectl get pod,svc [root@k8s-master ~]# kubectl get svc -n kubernetes-dashboard NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE dashboard-metrics-scraper ClusterIP 10.96.165.173 <none> 8000/TCP 110s kubernetes-dashboard NodePort 10.96.95.234 <none> 443:30001/TCP 110s访问地址：https://NodeIP:Port
默认Dashboard只能集群内部访问，修改Service为NodePort类型，暴露到外部：
kind: Service apiVersion: v1 metadata: labels: k8s-app: kubernetes-dashboard name: kubernetes-dashboard namespace: kubernetes-dashboard spec: type: NodePort "添加" ports: - port: 443 targetPort: 8443 nodePort: 30001 "添加" selector: k8s-app: kubernetes-dashboard访问地址：http://NodeIP:30001
创建service account并绑定默认cluster-admin管理员集群角色：
kubectl create serviceaccount dashboard-admin -n kube-system kubectl create clusterrolebinding dashboard-admin --clusterrole=cluster-admin --serviceaccount=kube-system:dashboard-admin kubectl describe secrets -n kube-system $(kubectl -n kube-system get secret | awk '/dashboard-admin/{print $1}')使用输出的token登录Dashboard。
