前置虚拟机环境

每个虚拟机配置一次就好

#关闭防火墙
systemctl stop firewalld
systemctl disable firewalld
#关闭 selinux
sed -i 's/enforcing/disabled/' /etc/selinux/config # 永久
setenforce 0 # 临时
#关闭 swap
swapoff -a # 临时
vim /etc/fstab # 永久
#将桥接的 IPv4 流量传递到 iptables 的链
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
#时间同步
yum install ntpdate -y
ntpdate time.windows.com

#主机名
hostnamectl set-hostname <hostname>

#在 master 添加 hosts：
cat >> /etc/hosts << EOF
192.168.235.139 k8s-master
192.168.235.133 k8s-node1
192.168.235.134 k8s-node2
EOF

没有Docker需要先安装并更换镜像源

添加 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

安装 kubeadm，kubelet 和 kubectl

yum install -y kubelet kubeadm kubectl
systemctl enable kubelet

正式部署

在 192.168.235.139（Master）执行

kubeadm init \
--apiserver-advertise-address=192.168.235.139 \
--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

这条指令执行完后会自动部署k8s的容器，执行完成后会有

kubeadm join 192.168.235.139:6443 --token 5l9p1e.xzn5a7jv3j75l9v0     --discovery-token-ca-cert-hash sha256:41a451baae921a44253243fc54ce7efb604db7df42fb541802337d08868a4a73 

此时在从节点输入上述指令，即可加入集群

kubectl get nodes #测试

执行完后正常应该是都ready了，然后docker ps集群的各个节点也会多出很多k8s相关容器

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

这个我没加后面也能跑。。。

安装 Pod 网络插件（CNI）

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

确保能够访问到 quay.io 这个 registery。如果 Pod 镜像下载失败，可以改这个镜像地址
这个不一定能连上，首先要试试

ping baidu.com

看能不能ping通外网
不行的话需要在DNS加个114.114.114.114
具体参考解决：ping: www.baidu.com: 未知的名称或服务

能ping通外网以后可以把raw.githubusercontent.com换成镜像源或者添加对应的ip，这个网上有相应教程，搜这个网址的关键词就行

或者直接自己创建

cat <<EOF > kube-flannel.yml
---
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: rancher/mirrored-flannelcni-flannel-cni-plugin:v1.0.0
        command:
        - cp
        args:
        - -f
        - /flannel
        - /opt/cni/bin/flannel
        volumeMounts:
        - name: cni-plugin
          mountPath: /opt/cni/bin
      - name: install-cni
        image: quay.io/coreos/flannel:v0.15.1
        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: quay.io/coreos/flannel:v0.15.1
        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
        volumeMounts:
        - name: run
          mountPath: /run/flannel
        - name: flannel-cfg
          mountPath: /etc/kube-flannel/
      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
EOF

应用配置

kubectl apply –f kube-flannel.yml

检验结果

kubectl get pods -n kube-system | grep kube-flannel

kubectl get pod -n kube-system -o wide

如果有Error或者其他非Running情况：
查看具体报错情况

kubectl describe pod kube-flannel-ds-xxxx -n kube-system

如果是pull image出错：
注意上面kube-flannel.yml用到了2个image，那需要手动拉取

docker pull rancher/mirrored-flannelcni-flannel-cni-plugin:v1.0.0
docker puil quay.io/coreos/flannel:v0.15.1

这里尤其需要注意，K8S把POD分配在了哪个节点，我这里是master，那就必须在master pull
测试 kubernetes 集群

kubectl create deployment nginx --image=nginx
kubectl expose deployment nginx --port=80 --type=NodePort
kubectl get pod,svc

集群中的任一节点ip都能访问pod

BUG解决

究极解决方案：删除K8S所有配置直接重装
什么unready基本都能解决

kubeadm reset
rm -rf $HOME/.kube

删除后直接从kubeadm init开始重装

参考文章：
kubernetes 坑人的错误！！！Unable to connect to the server: x509: certificate signed by unknown authority