一、系统配置（所有节点都需要执行）

1. 关闭防火墙

    systemctl stop firewalld
    systemctl disable firewalld
   

2. 禁用SELinux

    setenforce 0
   

编辑文件/etc/selinux/config，将SELINUX修改为disabled，如下：

SELINUX=disabled
3. 关闭系统Swap

	swapoff -a

4. 系统参数配置

    cat <<EOF >  /etc/sysctl.d/k8s.conf
    net.bridge.bridge-nf-call-ip6tables = 1
    net.bridge.bridge-nf-call-iptables = 1
    EOF
    sysctl --system
   

二、安装Docker

	cat > /etc/yum.repos.d/docker-ce.repo <<-EOF
	[docker-ce-stable]
	name=Docker CE Stable Mirror Repository
	baseurl=https://mirrors.aliyun.com/docker-ce/linux/centos/7/x86_64/stable
	enabled=0
	gpgcheck=1
	gpgkey=https://mirrors.aliyun.com/docker-ce/linux/centos/gpg
	EOF

	yum install --enablerepo=docker-ce-stable -y docker-ce-18.06.1.ce

配置加速器

	cat > /etc/docker/daemon.json <<-EOF
	{
	    "registry-mirrors": [
	        "https://registry.docker-cn.com",
	        "https://registry.cn-hangzhou.aliyuncs.com"
	    ],
	    "exec-opts": [
	        "native.cgroupdriver=systemd"
	    ]
	}
	EOF
 
systemctl enable docker
systemctl start docker

三、安装Kubernetes组件

1. 安装kubectl,kubeadm,kubelet（master节点上执行）

    wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo
    wget -O /etc/yum.repos.d/epel.repo http://mirrors.aliyun.com/repo/Centos-7.repo
     
    cat <<EOF > /etc/yum.repos.d/kubernetes.repo
    [kubernetes]
    name=Kubernetes
    baseurl=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64
    enabled=1
    gpgcheck=0
    EOF
   
    yum clean all 
    yum makecache
   

查看可用的版本并安装

yum list --showduplicates | grep 'kubeadm\|kubectl\|kubelet'

yum install kubeadm-1.15.0 kubectl-1.15.0 kubelet-1.15.0 --disableexcludes=kubernetes

systemctl enable --now kubelet
备注：此处启动kubelet后会启动失败，因为缺少相关的配置，后续初始化后会自动生成

2. 初始化Master节点（master节点上执行）
   执行如下命令进行初始化

    kubeadm init --image-repository=registry.aliyuncs.com/google_containers --pod-network-cidr=172.17.0.0/16 --kubernetes-version=v1.15.0
   

–image-repository 初始化过程中需要拉取一些镜像，可用使用ali的镜像仓库，也可以提前将镜像下载下来
–pod-network-cidr 指定 Pod 网络的范围。Kubernetes 支持多种网络方案，而且不同网络方案对 --pod-network-cidr 有自己的要求
–kubernetes-version 版本号
初始化成功后会有如下信息（截取部分）

Your Kubernetes master 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/
You can now join any number of machines by running the following on each node
as root:
kubeadm join 172.16.9.201:6443 --token mjcpfv.ygwck7pjyue68fw9 --discovery-token-ca-cert-hash sha256:6c31a69d3bfa45a5dd50de2e07f1c71731d17244a009742a3dbf83e03a5a62f6

3. 加入node节点（node节点上执行）
   使用最后的kubeadm可以用来在其他Node节点上执行，以将其他节点加入到集群中，在接下来的章节会用到。

4. 配置kubectl认证信息
   非root用户

    mkdir -p $HOME/.kube
    sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
    sudo chown $(id -u):$(id -g) $HOME/.kube/config
    root用户
    
    echo "export KUBECONFIG=/etc/kubernetes/admin.conf" >> ~/.bash_profile
    source ~/.bash_profile
   

5. 安装flannel网络

    kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/bc79dd1505b0c8681ece4de4c0d86c5cd2643275/Documentation/kube-flannel.yml
   

查看Pod信息

kubectl --namespace=kube-system get pod

6. 查看集群信息
   [root@k8s-node1 ~]# kubectl get node
   NAME STATUS ROLES AGE VERSION
   k8s-node1 Ready master 157m v1.15.0
   k8s-node2 Ready 152m v1.15.0
   k8s-node3 Ready 152m v1.15.0
   [root@k8s-node1 ~]#
   [root@k8s-node1 ~]# kubectl get cs
   NAME STATUS MESSAGE ERROR
   controller-manager Healthy ok
   scheduler Healthy ok
   etcd-0 Healthy {“health”:“true”}