0 机器资源定义
虚拟机我们准备三台CentOS7服务器（一个master,两个node），并且给他们分配静态ip，静态ip配置可以参考我的这篇文章

192.168.150.100 k8s-master01

192.168.150.110 k8s-node01

192.168.150.120 k8s-node01

设置主机名称（重要）

 hostnamectl  set-hostname k8s-master01
 hostnamectl  set-hostname k8s-node01
 hostnamectl  set-hostname k8s-node02

1 配置hosts（重要）

vi /etc/hosts

192.168.67.200 k8s-master01

192.168.67.201 k8s-node01

192.168.67.202 k8s-node01

2 检查系统版本
需要保证系统内核为7.5以上，否则可能会有位置错误

3 关闭安全selinux和swap虚拟内存

swap为虚拟内存，会降低k8s性能，同时也可以减少不必要的安装问题

swapoff -a && sed -i '/ swap / s/^\(.*\)$/#\1/g' /etc/fstab

selinux是linux系统下的一个安全服务，可是安装k8s的时候它的存在并不是一件好事

setenforce 0 && sed -i 's/^SELINUX=.*/SELINUX=disabled/' /etc/selinux/config

4 同步时间
k8s要求各个节点时间强一致

# 启动chronyd服务
[root@master ~]# systemctl start chronyd
[root@master ~]# systemctl enable chronyd
[root@master ~]# date

5 禁用防火墙

kubernetes和docker 在运行的中会产生大量的iptables规则，为了不让系统规则跟它们混淆，直接关闭系统的规则

# 1 关闭firewalld服务
[root@master ~]# systemctl stop firewalld
[root@master ~]# systemctl disable firewalld
# 2 关闭iptables服务
[root@master ~]# systemctl stop iptables
[root@master ~]# systemctl disable iptables

6.修改内核参数

vi /etc/sysctl.d/kubernetes.conf

把下方内容粘贴进去

# 修改linux的内核采纳数，添加网桥过滤和地址转发功能
# 编辑/etc/sysctl.d/kubernetes.conf文件，添加如下配置：
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
net.ipv4.ip_forward = 1

重新加载并检验

# 重新加载配置
[root@master ~]# sysctl -p
# 加载网桥过滤模块
[root@master ~]# modprobe br_netfilter
# 查看网桥过滤模块是否加载成功
[root@master ~]# lsmod | grep br_netfilter

7.配置ipvs

在Kubernetes中Service有两种带来模型，一种是基于iptables的，一种是基于ipvs的两者比较的话，ipvs的性能明显要高一些，但是如果要使用它，需要手动载入ipvs模块

# 1.安装ipset和ipvsadm
[root@master ~]# yum install ipset ipvsadmin -y

# 2.添加需要加载的模块写入脚本文件
[root@master ~]# cat <<EOF> /etc/sysconfig/modules/ipvs.modules
#!/bin/bash
modprobe -- ip_vs
modprobe -- ip_vs_rr
modprobe -- ip_vs_wrr
modprobe -- ip_vs_sh
modprobe -- nf_conntrack_ipv4
EOF

# 3.为脚本添加执行权限
[root@master ~]# chmod +x /etc/sysconfig/modules/ipvs.modules

# 4.执行脚本文件
[root@master ~]# /bin/bash /etc/sysconfig/modules/ipvs.modules

# 5.查看对应的模块是否加载成功
[root@master ~]# lsmod | grep -e ip_vs -e nf_conntrack_ipv4

这里建议给三个节点拍个快照后再继续下面的步骤
8.安装docker

# 1、切换镜像源
wget https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo -O /etc/yum.repos.d/docker-ce.repo

如果没有wget命令可以更新一下yum源，然后使用yum安装

yum update

yum instatll wget

# 2、查看当前镜像源中支持的docker版本(可以跳过安装指定版本即可)
yum list docker-ce --showduplicates

# 3、安装特定版本的docker-ce
# 必须制定--setopt=obsoletes=0，否则yum会自动安装更高版本
[root@master ~]# yum install --setopt=obsoletes=0 docker-ce-18.06.3.ce-3.el7 -y

# 4、添加一个配置文件
#Docker 在默认情况下使用Vgroup Driver为cgroupfs，而Kubernetes推荐使用systemd来替代cgroupfs
[root@master ~]# mkdir /etc/docker
[root@master ~]# cat <<EOF> /etc/docker/daemon.json
{
	"exec-opts": ["native.cgroupdriver=systemd"],
	"registry-mirrors": ["https://kn0t2bca.mirror.aliyuncs.com"]
}
EOF

# 5、启动dokcer
[root@master ~]# systemctl restart docker
[root@master ~]# systemctl enable docker

这里建议给三个节点拍完快照后继续下面的操作
9.安装k8s组件

# 1、由于kubernetes的镜像在国外，速度比较慢，这里切换成国内的镜像源
vi /etc/yum.repos.d/kubernetes.repo

写入下面的内容

# 2、编辑/etc/yum.repos.d/kubernetes.repo,添加下面的配置
[kubernetes]
name=Kubernetes
baseurl=http://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64
enabled=1
gpgchech=0
repo_gpgcheck=0
gpgkey=http://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg
			http://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg

# 3、安装kubeadm、kubelet和kubectl
yum install --setopt=obsoletes=0 kubeadm-1.17.4-0 kubelet-1.17.4-0 kubectl-1.17.4-0 -y

# 4、配置kubelet的cgroup
#编辑/etc/sysconfig/kubelet, 添加下面的配置

vi /etc/sysconfig/kubelet

KUBELET_CGROUP_ARGS="--cgroup-driver=systemd"
KUBE_PROXY_MODE="ipvs"

# 5、设置kubelet开机自启
systemctl enable kubelet

建议在此处拍过快照后进行下面的操作
10.准备集群镜像
在三个服务器中定义变量并使用for循环下载需要的镜像

images=(
	kube-apiserver:v1.17.4
	kube-controller-manager:v1.17.4
	kube-scheduler:v1.17.4
	kube-proxy:v1.17.4
	pause:3.1
	etcd:3.4.3-0
	coredns:1.6.5
)

for imageName in ${images[@]};do
	docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/$imageName
	docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/$imageName k8s.gcr.io/$imageName
	docker rmi registry.cn-hangzhou.aliyuncs.com/google_containers/$imageName 
done

11.集群初始
下面的操作只需要在master节点上执行即可化

kubeadm init \
	--apiserver-advertise-address=你的masterip \
	--image-repository registry.aliyuncs.com/google_containers \
	--kubernetes-version=v1.17.4 \
	--service-cidr=10.96.0.0/12 \
	--pod-network-cidr=10.244.0.0/16

创建后我们根据提示创建必要的文件

# 创建必要文件 创建后会给出提示
[root@master ~]# mkdir -p $HOME/.kube
[root@master ~]# sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
[root@master ~]# sudo chown $(id -u):$(id -g) $HOME/.kube/config

同时为了让master可以控制node我们也需要根据图片中的提示在node节点中执行相应的命令（下面的要换成自己的）

kubeadm join 192.168.67.200:6443 --token ghlcxv.8rxxw24d7gzlnqcw \
    --discovery-token-ca-cert-hash sha256:854071f748b04c41a53961c39902c38749cd643874bc8731a154c99a6d9cc1ea

检验master可以感知到的节点

因为现在还没有在master中安装网络插件所以节点之间还不能进行通信，所以STATUS为NotReady.

kubectl apply -f kube-flannel.yml

注 kube-flannel.yml文件需要单独下载

wget https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml

你也可以拷贝下面的内容进行使用，只需要将文件名称改成与命令中一致即可

---
apiVersion: policy/v1beta1
kind: PodSecurityPolicy
metadata:
  name: psp.flannel.unprivileged
  annotations:
    seccomp.security.alpha.kubernetes.io/allowedProfileNames: docker/default
    seccomp.security.alpha.kubernetes.io/defaultProfileName: docker/default
    apparmor.security.beta.kubernetes.io/allowedProfileNames: runtime/default
    apparmor.security.beta.kubernetes.io/defaultProfileName: runtime/default
spec:
  privileged: false
  volumes:
  - configMap
  - secret
  - emptyDir
  - hostPath
  allowedHostPaths:
  - pathPrefix: "/etc/cni/net.d"
  - pathPrefix: "/etc/kube-flannel"
  - pathPrefix: "/run/flannel"
  readOnlyRootFilesystem: false
  # Users and groups
  runAsUser:
    rule: RunAsAny
  supplementalGroups:
    rule: RunAsAny
  fsGroup:
    rule: RunAsAny
  # Privilege Escalation
  allowPrivilegeEscalation: false
  defaultAllowPrivilegeEscalation: false
  # Capabilities
  allowedCapabilities: ['NET_ADMIN', 'NET_RAW']
  defaultAddCapabilities: []
  requiredDropCapabilities: []
  # Host namespaces
  hostPID: false
  hostIPC: false
  hostNetwork: true
  hostPorts:
  - min: 0
    max: 65535
  # SELinux
  seLinux:
    # SELinux is unused in CaaSP
    rule: 'RunAsAny'
---
kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: flannel
rules:
- apiGroups: ['extensions']
  resources: ['podsecuritypolicies']
  verbs: ['use']
  resourceNames: ['psp.flannel.unprivileged']
- apiGroups:
  - ""
  resources:
  - pods
  verbs:
  - get
- apiGroups:
  - ""
  resources:
  - nodes
  verbs:
  - list
  - watch
- apiGroups:
  - ""
  resources:
  - nodes/status
  verbs:
  - patch
---
kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: flannel
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: flannel
subjects:
- kind: ServiceAccount
  name: flannel
  namespace: kube-system
---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: flannel
  namespace: kube-system
---
kind: ConfigMap
apiVersion: v1
metadata:
  name: kube-flannel-cfg
  namespace: kube-system
  labels:
    tier: node
    app: flannel
data:
  cni-conf.json: |
    {
      "name": "cbr0",
      "cniVersion": "0.3.1",
      "plugins": [
        {
          "type": "flannel",
          "delegate": {
            "hairpinMode": true,
            "isDefaultGateway": true
          }
        },
        {
          "type": "portmap",
          "capabilities": {
            "portMappings": true
          }
        }
      ]
    }
  net-conf.json: |
    {
      "Network": "10.244.0.0/16",
      "Backend": {
        "Type": "vxlan"
      }
    }
---
apiVersion: apps/v1
kind: DaemonSet
metadata:
  name: kube-flannel-ds
  namespace: kube-system
  labels:
    tier: node
    app: flannel
spec:
  selector:
    matchLabels:
      app: flannel
  template:
    metadata:
      labels:
        tier: node
        app: flannel
    spec:
      affinity:
        nodeAffinity:
          requiredDuringSchedulingIgnoredDuringExecution:
            nodeSelectorTerms:
            - matchExpressions:
              - key: kubernetes.io/os
                operator: In
                values:
                - linux
      hostNetwork: true
      priorityClassName: system-node-critical
      tolerations:
      - operator: Exists
        effect: NoSchedule
      serviceAccountName: flannel
      initContainers:
      - name: install-cni
        image: quay.io/coreos/flannel:v0.14.0
        command:
        - cp
        args:
        - -f
        - /etc/kube-flannel/cni-conf.json
        - /etc/cni/net.d/10-flannel.conflist
        volumeMounts:
        - name: cni
          mountPath: /etc/cni/net.d
        - name: flannel-cfg
          mountPath: /etc/kube-flannel/
      containers:
      - name: kube-flannel
        image: quay.io/coreos/flannel:v0.14.0
        command:
        - /opt/bin/flanneld
        args:
        - --ip-masq
        - --kube-subnet-mgr
        resources:
          requests:
            cpu: "100m"
            memory: "50Mi"
          limits:
            cpu: "100m"
            memory: "50Mi"
        securityContext:
          privileged: false
          capabilities:
            add: ["NET_ADMIN", "NET_RAW"]
        env:
        - name: POD_NAME
          valueFrom:
            fieldRef:
              fieldPath: metadata.name
        - name: POD_NAMESPACE
          valueFrom:
            fieldRef:
              fieldPath: metadata.namespace
        volumeMounts:
        - name: run
          mountPath: /run/flannel
        - name: flannel-cfg
          mountPath: /etc/kube-flannel/
      volumes:
      - name: run
        hostPath:
          path: /run/flannel
      - name: cni
        hostPath:
          path: /etc/cni/net.d
      - name: flannel-cfg
        configMap:
          name: kube-flannel-cfg

运行完毕后需要等待大概两分钟左右，具体时间和虚拟机的配置有关。


k8s环境至安装完毕，建议拍快照后，再进行其他实验学习