需要三台虚拟机，一台master两台node节点，这里我们使用的是VMware，每台虚拟机2核+4G内存
1、安装docker的yum源

wget https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo -O  /etc/yum.repos.d/docker-ce.repo

2、安装docker，这里我们选择的是18版本

yum -y install docker-ce-18.06.1.ce-3.el7

3、启动docker

systemctl enable docker && systemctl start docker

4、关闭防火墙

systemctl stop firewalld
systemctl disable firewalld

5、关闭 selinux

sed -i 's/SELINUX=enforcing/SELINUX=disabled/g' /etc/selinux/config # 永久关闭,需要重启实例
setenforce 0 # 临时关闭，无需重启实例

6、关闭swap

swapoff -a # 临时关闭
vim /etc/fstab # 永久关闭
#注释掉swap这行
# /dev/mapper/centos-swap swap                    swap    defaults        0 0

systemctl reboot  #重启生效
free -m  #查看下swap交换区是否都为0，如果都为0则swap关闭成功

7、设置主机名

hostnamectl set-hostname <hostname>

8、在master节点修改hosts

cat >> /etc/hosts << EOF
192.168.142.128 master1
192.168.142.129 node1
192.168.142.130 node2
EOF

9、将桥接的IPv4流量传递到iptables

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

sysctl --system # 生效

10、设置时间同步

yum install ntpdate -y
ntpdate time.windows.com 

11、添加k8s yum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
EOF

12、卸载旧版本

yum remove -y kubelet kubeadm kubectl

13、查看可以安装的版本

yum list kubelet --showduplicates | sort -r

14、安装kubelet、kubeadm、kubectl 指定版本，我们使用kubeadm方式安装k8s集群

yum install -y kubelet-1.18.0 kubeadm-1.18.0 kubectl-1.18.0

15、开机启动kubelet

systemctl enable kubelet
systemctl start kubelet

16、在master机器上执行初始化操作

kubeadm init --apiserver-advertise-address=:masterIP --image-repository registry.aliyuncs.com/google_containers --kubernetes-version v1.18.0 --service-cidr=10.96.0.0/12 --pod-network-cidr=10.244.0.0/16

出现以下情况代表初始化成功，执行需要执行的代码

17、master执行

mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config

18、在mater上执行，安装pod网络插件

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

(如果网络插件有问题，可以直接到github上找kube-flannel.yml内容https://github.com/flannel-io/flannel/blob/master/Documentation/kube-flannel.yml)
将内容黏贴到master节点的文件里，执行kubectl apply -f kube-flannel.yml
内容我会放到最后

19、在node节点执行，加入master集群

kubeadm join 192.168.142.128:6443 --token qwha7h.bdg51dz4h9oali2a \
    --discovery-token-ca-cert-hash sha256:271c6fc7326e41c420a3410e3c194765ab169f40ca5b2d4adff3f6a8d255d0cc 

如果status不是ready状态可以使用下面命令查看问题

journalctl -f -u kubelet.service

本人也在学习k8s相关技术，这个是本地测试环境，正式环境肯定不能只有1个master节点，在后续的学习过程中还会持续更新

最后我直接复制出kube-flannel.yml内容

---
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-plugin
       #image: flannelcni/flannel-cni-plugin:v1.1.0 for ppc64le and mips64le (dockerhub limitations may apply)
        image: rancher/mirrored-flannelcni-flannel-cni-plugin:v1.1.0
        command:
        - cp
        args:
        - -f
        - /flannel
        - /opt/cni/bin/flannel
        volumeMounts:
        - name: cni-plugin
          mountPath: /opt/cni/bin
      - name: install-cni
       #image: flannelcni/flannel:v0.18.1 for ppc64le and mips64le (dockerhub limitations may apply)
        image: rancher/mirrored-flannelcni-flannel:v0.18.1
        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: flannelcni/flannel:v0.18.1 for ppc64le and mips64le (dockerhub limitations may apply)
        image: rancher/mirrored-flannelcni-flannel:v0.18.1
        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
        - name: EVENT_QUEUE_DEPTH
          value: "5000"
        volumeMounts:
        - name: run
          mountPath: /run/flannel
        - name: flannel-cfg
          mountPath: /etc/kube-flannel/
        - name: xtables-lock
          mountPath: /run/xtables.lock
      volumes:
      - name: run
        hostPath:
          path: /run/flannel
      - name: cni-plugin
        hostPath:
          path: /opt/cni/bin
      - name: cni
        hostPath:
          path: /etc/cni/net.d
      - name: flannel-cfg
        configMap:
          name: kube-flannel-cfg
      - name: xtables-lock
        hostPath:
          path: /run/xtables.lock
          type: FileOrCreate