一、前言

上一节介绍了 Kubernetes (k8s) 内网集群的搭建详细图解 ，也介绍了云服务器按量付费的租赁方式，但是这种方式有点不好之处就是，每次停机重启之后 ， IP地址就变了，导致XShell 连接工具每次要改IP， 很是麻烦， 好在我这个人比较能薅羊毛，于是在腾讯云， 百度云， 阿里云上面都薅了一波羊毛。所以趁着休息，将手头的几台云服务器搭建成 k8s 集群，由于这几台云服务属于不同的云服务厂商，无法搭建局域网环境的 k8s 集群，故笔者搭建的是公网环境的 k8s 集群。

二、环境准备

我这边薅的羊毛配置如下：

• 开启 6443 TCP端口：给 kube-apiserver 使用
• 开启 8472 UPD端口：给 flannel 网络插件通讯使用
• 开启TCP 30000-32767 范围的端口：NodePort 服务
• 每台机器都设置成不同的hostname

  • # 1、三台机器一次运行下面的命令， 设置不同的hostname
    # 语法格式：hostnamectl set-hostname xxx
    hostnamectl set-hostname master
    hostnamectl set-hostname node1
    hostnamectl set-hostname node2
    
    # 2、重启服务器
    reboot
    

• 将 SELinux 设置为 permissive 模式（相当于将其禁用）

  • sudo setenforce 0
    sudo sed -i 's/^SELINUX=enforcing$/SELINUX=permissive/' /etc/selinux/config

• 关闭swap

  • # 临时关闭swap分区，当前会话生效，重启失效
    swapoff -a  
    # 永久关闭swap分区
    sed -ri 's/.*swap.*/#&/' /etc/fstab

• 允许 iptables 检查桥接流量

  • cat <<EOF | sudo tee /etc/modules-load.d/k8s.conf
    br_netfilter
    EOF
    
    cat <<EOF | sudo tee /etc/sysctl.d/k8s.conf
    net.bridge.bridge-nf-call-ip6tables = 1
    net.bridge.bridge-nf-call-iptables = 1
    EOF
    sudo sysctl --system

三、环境搭建

1、创建虚拟网卡

由于云主机网卡绑定的都是内网 IP, 而且几台云服务器位于不同的内网中（VPC网络不互通）, 直接搭建会将内网 IP 注册进集群导致搭建不成功。

解决方案：使用虚拟网卡绑定公网 IP, 使用该公网 IP 来注册集群。

# 所有主机都要创建虚拟网卡，并绑定对应的公网 ip
# 临时生效，重启会失效
ifconfig eth0:1 <你的公网IP>

# 永久生效
cat > /etc/sysconfig/network-scripts/ifcfg-eth0:1 <<EOF
BOOTPROTO=static
DEVICE=eth0:1
IPADDR=<你的公网IP>
PREFIX=32
TYPE=Ethernet
USERCTL=no
ONBOOT=yes
EOF

2、安装Docker

这里就不在赘述了， 不知道如何安装的请看我的另外一篇博客

注：由于k8s 和 Docker 版本差异， 可能会产生错误。所以请使用 “yum install -y docker-ce-19.03.13 docker-ce-cli-19.03.13 containerd.io” 替换下述链接的第 8 步的命令。

Linux 下安装Docker图解教程https://blog.csdn.net/IT_rookie_newbie/article/details/120687531

3、安装Kubernetes

3.1、安装kubelet、kubeadm、kubectl (每台机器都需要执行)

cat <<EOF | sudo tee /etc/yum.repos.d/kubernetes.repo
[kubernetes]
name=Kubernetes
baseurl=http://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64
enabled=1
gpgcheck=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
exclude=kubelet kubeadm kubectl
EOF


sudo yum install -y kubelet-1.20.9 kubeadm-1.20.9 kubectl-1.20.9 --disableexcludes=kubernetes

sudo systemctl enable --now kubelet

3.2、安装kubeadm引导集群（每台机器都需要执行）

sudo tee ./images.sh <<-'EOF'
#!/bin/bash
images=(
kube-apiserver:v1.20.9
kube-proxy:v1.20.9
kube-controller-manager:v1.20.9
kube-scheduler:v1.20.9
coredns:1.7.0
etcd:3.4.13-0
pause:3.2
)
for imageName in ${images[@]} ; do
docker pull registry.cn-hangzhou.aliyuncs.com/lfy_k8s_images/$imageName
done
EOF
   
chmod +x ./images.sh && ./images.sh

3.3、修改kubelet启动参数文件（每台机器都需要执行） 

# 此文件安装kubeadm后就存在了
vim /usr/lib/systemd/system/kubelet.service.d/10-kubeadm.conf

# 注意，这步很重要，如果不做，节点仍然会使用内网IP注册进集群
# 在末尾添加参数 --node-ip=公网IP
ExecStart=/usr/bin/kubelet $KUBELET_KUBECONFIG_ARGS $KUBELET_CONFIG_ARGS $KUBELET_KUBEADM_ARGS $KUBELET_EXTRA_ARGS --node-ip=<公网IP>

3.4、添加配置文件（只在master 主节点执行）

# 添加配置文件，注意替换下面的IP
cat > kubeadm-config.yaml <<EOF
apiVersion: kubeadm.k8s.io/v1beta2
kind: ClusterConfiguration
kubernetesVersion: v1.20.9
apiServer:
  certSANs: 
  - master        #请替换为hostname
  - xx.xx.xx.xx   #请替换为公网IP
  - xx.xx.xx.xx   #请替换为私网IP
  - 10.96.0.1
controlPlaneEndpoint: xx.xx.xx.xx:6443 #替换为公网IP
imageRepository: registry.cn-hangzhou.aliyuncs.com/lfy_k8s_images
networking:
  podSubnet: 10.244.0.0/16
  serviceSubnet: 10.96.0.0/12
--- 
apiVersion: kubeproxy-config.k8s.io/v1alpha1
kind: KubeProxyConfiguration
featureGates:
  SupportIPVSProxyMode: true
mode: ipvs
EOF

3.5、初始化主节点（只在master 主节点执行）

kubeadm init --config=kubeadm-config.yaml

3.6、执行命令

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

3.7、修改kube-apiserver参数（master，只修改注释项，其余的不要动）

# 修改两个信息，添加--bind-address和修改--advertise-address
vim /etc/kubernetes/manifests/kube-apiserver.yaml

apiVersion: v1
kind: Pod
metadata:
  annotations:
    kubeadm.kubernetes.io/kube-apiserver.advertise-address.endpoint: 10.0.20.8:6443
  creationTimestamp: null
  labels:
    component: kube-apiserver
    tier: control-plane
  name: kube-apiserver
  namespace: kube-system
spec:
  containers:
  - command:
    - kube-apiserver
    - --advertise-address=xx.xx.xx.xx # 修改为公网IP
    - --bind-address=0.0.0.0  # 新增参数
    - --allow-privileged=true
    - --authorization-mode=Node,RBAC
    - --client-ca-file=/etc/kubernetes/pki/ca.crt
    - --enable-admission-plugins=NodeRestriction
    - --enable-bootstrap-token-auth=true
    - --etcd-cafile=/etc/kubernetes/pki/etcd/ca.crt
    - --etcd-certfile=/etc/kubernetes/pki/apiserver-etcd-client.crt
    - --etcd-keyfile=/etc/kubernetes/pki/apiserver-etcd-client.key
    - --etcd-servers=https://127.0.0.1:2379
    - --insecure-port=0
    - --kubelet-client-certificate=/etc/kubernetes/pki/apiserver-kubelet-client.crt
    - --kubelet-client-key=/etc/kubernetes/pki/apiserver-kubelet-client.key
    - --kubelet-preferred-address-types=InternalIP,ExternalIP,Hostname
    - --proxy-client-cert-file=/etc/kubernetes/pki/front-proxy-client.crt
    - --proxy-client-key-file=/etc/kubernetes/pki/front-proxy-client.key
    - --requestheader-allowed-names=front-proxy-client
    - --requestheader-client-ca-file=/etc/kubernetes/pki/front-proxy-ca.crt
    - --requestheader-extra-headers-prefix=X-Remote-Extra-
    - --requestheader-group-headers=X-Remote-Group
    - --requestheader-username-headers=X-Remote-User
    - --secure-port=6443
    - --service-account-issuer=https://kubernetes.default.svc.cluster.local
    - --service-account-key-file=/etc/kubernetes/pki/sa.pub
    - --service-account-signing-key-file=/etc/kubernetes/pki/sa.key
    - --service-cluster-ip-range=10.96.0.0/12
    - --tls-cert-file=/etc/kubernetes/pki/apiserver.crt
    - --tls-private-key-file=/etc/kubernetes/pki/apiserver.key
    image: registry.cn-hangzhou.aliyuncs.com/lfy_k8s_images/kube-apiserver:v1.20.9
    imagePullPolicy: IfNotPresent
    livenessProbe:
      failureThreshold: 8
      httpGet:
        host: 10.0.20.8
        path: /livez
        port: 6443
        scheme: HTTPS
      initialDelaySeconds: 10
      periodSeconds: 10
      timeoutSeconds: 15
    name: kube-apiserver
    readinessProbe:
      failureThreshold: 3
      httpGet:
        host: 10.0.20.8
        path: /readyz
        port: 6443
        scheme: HTTPS
      periodSeconds: 1
      timeoutSeconds: 15
    resources:
      requests:
        cpu: 250m
    startupProbe:
      failureThreshold: 24
      httpGet:
        host: 10.0.20.8
        path: /livez
        port: 6443
        scheme: HTTPS
      initialDelaySeconds: 10
      periodSeconds: 10
      timeoutSeconds: 15
    volumeMounts:
    - mountPath: /etc/ssl/certs
      name: ca-certs
      readOnly: true
    - mountPath: /etc/pki
      name: etc-pki
      readOnly: true
    - mountPath: /etc/kubernetes/pki
      name: k8s-certs
      readOnly: true
  hostNetwork: true
  priorityClassName: system-node-critical
  volumes:
  - hostPath:
      path: /etc/ssl/certs
      type: DirectoryOrCreate
    name: ca-certs
  - hostPath:
      path: /etc/pki
      type: DirectoryOrCreate
    name: etc-pki
  - hostPath:
      path: /etc/kubernetes/pki
      type: DirectoryOrCreate
    name: k8s-certs
status: {}

3.8、安装flannel网络插件（只在master 主节点执行）

flanel Git地址：flannel

# 1、下载flannel配置文件
wget https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml

修改 kube-flannel.yml内容，如下：

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",  # 这里是kubeadm-config.yaml配置的podsnetwork
      "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
        - --public-ip=$(PUBLIC_IP)  # 新增
        - --iface=eth0   # 新增
        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: PUBLIC_IP #新增
          valueFrom:   #新增
            fieldRef: #新增
              fieldPath: status.podIP #新增
        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

 创建网络插件 

kubectl apply -f kube-flannel.yml

3.9、将 node1 和 node2 节点加入工作节点

在工作节点(node1 , node2) 上执行上述初始化结果中的令牌内容

kubeadm join k8s-master:6443 --token kqi0e4.j8v7dg0qxx4i3re9 \
    --discovery-token-ca-cert-hash sha256:b8b22ee57294e3c9e4bf09d40ec46dfd2fbb3b07287d512361380fb6b3da019a

 注：这个命令24小时内有效，如果超出了时间范围就执行 “kubeadm token create --print-join-command” ，重新生成一个令牌即可。

3.10、验证集群

在master 节点上使用 “kubectl get nodes” 来验证集群

如果端口 ping 不通，检查是否开启了“环境准备” 中提到的相关端口。

四、部署dashboard（只在master 主节点执行）

这里就不在赘述了， 可以去看我的另外一篇文章 ： “二、Kubernetes (k8s) 内网集群的搭建详细图解_胖太乙的博客-CSDN博客”