基于KubeAdm搭建多节点K8S集群

环境准备

安装docker（主节点+工作节点）

1. 先安装yml

yum install -y yum-utils device-mapper-persistent-data lvm2

2. 设置阿里云镜像

sudo yum-config-manager --add-repo http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo

3. 查看可安装的docker版本

yum list docker-ce --showduplicates | sort -r

4. 安装docker

yum -y install docker-ce-20.10.10-3.el7

5. 查看docker版本

docker -v

6. 配置开机自启动

systemctl enable docker.service

7. 启动docker

systemctl start docker

8. 查看docker 启动状态

systemctl status docker

配置阿里云镜像源（主节点+工作节点）

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kubelet kubeadm kubectl（主节点+工作节点）

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

主节点初始化（主节点）

注意：只修改两个地方(master主机【内网IP】，k8s软件版本)

kubeadm init \
--apiserver-advertise-address=192.168.2.104 \
--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

主节点执行完命令需要执行

注意：每个环境命令有可能不一样，以操作指令的系统为准

添加工作节点

在主节点初始化完成后，会有对应的添加工作节点的命令，以下是教程的指令

kubeadm join 192.168.2.124:6443 --token gzwb0i.ldwvrk4lrnyjr9zr \
    --discovery-token-ca-cert-hash sha256:836ebbfa7179a125db9c1de8dbbbdd9cf2328f1054aac7241f6f519e0309d623

执行成功查看节点

kubectl get nodes

状态都是NotReady，需要配置网络插件

安装网络插件(主节点执行)

方式一 （教程使用这个方式，官方改了源，直接使用这个命令）

kubectl apply -f  https://raw.githubusercontent.com/flannel-io/flannel/master/Documentation/kube-flannel.yml

方式二 （上传 flannel.yaml ）

---
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']
  defaultAddCapabilities: []
  requiredDropCapabilities: []
  # Host namespaces
  hostPID: false
  hostIPC: false
  hostNetwork: true
  hostPorts:
  - min: 0
    max: 65535
  # SELinux
  seLinux:
    # SELinux is unsed in CaaSP
    rule: 'RunAsAny'
---
kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1beta1
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/v1beta1
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: |
    {
      "cniVersion": "0.2.0",
      "name": "cbr0",
      "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-amd64
  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: beta.kubernetes.io/os
                    operator: In
                    values:
                      - linux
                  - key: beta.kubernetes.io/arch
                    operator: In
                    values:
                      - amd64
      hostNetwork: true
      tolerations:
      - operator: Exists
        effect: NoSchedule
      serviceAccountName: flannel
      initContainers:
      - name: install-cni
        image: lizhenliang/flannel:v0.11.0-amd64 
        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: lizhenliang/flannel:v0.11.0-amd64 
        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"]
        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

查看节点状态

kubectl get nodes

查看系统pod状态

kubectl get pods -n kube-system

查看k8s集群信息

kubectl cluster-info

查看内部组件

kubectl get pod -A

搭建第一个K8S应用

创建deployment demo-nginx（Pod控制器的一种）

kubectl create deployment demo-nginx --image=nginx:1.23.0

查看deployment和pod

kubectl get deployment,pod,svc

暴露80端口，创建service

kubectl expose deployment demo-nginx --port=80 --type=NodePort

访问应用

在浏览器访问, 工作节点开放端口30646，访问工作节点ip：30646（网络安全组记得开放30646端口）

master、node节点访问这个 开放的端口都可以

在master、node节点访问

注意

• Minikube的搭建跟用Kubeadm的有一点不一样
• Kubeadm部署，暴露端口对外服务，会随机选端口，默认范围是30000~32767，可以修改指定