使用kubeadm部署Kubernetes集群(v1.20.0)

介绍

Kubeadm是一个K8s部署工具，提供kubeadm init和kubeadm join，用于快速部署Kubernetes集群。

环境准备

服务器要求：

• 建议最小硬件配置：2核CPU、2G内存、30G硬盘

• 服务器最好可以访问外网，会有从网上拉取镜像需求，如果服务器不能上网，需要提前下载对应镜像并导入节点

软件环境：

软件	版本
操作系统	CentOS 7.x 64位
容器引擎	Docker CE 19
Kubernetes	Kubernetes v1.20

服务器整体规划：

角色	IP	组件
k8s-master	10.0.8.10	kube-apiserver，kube-controller-manager，kube-scheduler，etcd
k8s-node	10.0.8.13	kubelet，kube-proxy，docker，etcd

操作系统初始化配置

# 关闭防火墙
systemctl stop firewalld
systemctl disable firewalld

# 永久关闭selinux 和 swap
sed -i 's/enforcing/disabled/' /etc/selinux/config
sed -ri 's/.*swap.*/#&/' /etc/fstab

# 根据规划设置主机名
hostnamectl set-hostname <hostname>

# 添加hosts
cat >> /etc/hosts << EOF
10.0.8.10 k8s-master
10.0.8.13 k8s-node
EOF

# 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 -y ntpdate
ntpdate time.windows.com

# ssh免密设置
ssh-keygen -t rsa
ssh-copy-id root@<HOST>

所有节点安装 Docker/kubeadm/kubelet

wget https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo -O /etc/yum.repos.d/docker-ce.repo
yum -y install docker-ce-19.03.9-3.el7 docker-ce-cli-19.03.9-3.el7
systemctl enable docker && systemctl start docker
docker --version

# 添加阿里云 YUM 软件源
cat > /etc/docker/daemon.json << EOF
{
  "registry-mirrors": ["https://b9pmyelo.mirror.aliyuncs.com"]
}
EOF

# 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

# 安装 kubeadm，kubelet 和 kubectl
yum install -y kubelet-1.20.0 kubeadm-1.20.0 kubectl-1.20.0
systemctl start docker
systemctl enable kubelet

部署 Kubernetes Master

# 在Master上执行，由于默认拉取镜像地址 k8s.gcr.io 国内无法访问，这里指定阿里云镜像仓库地址。
kubeadm init \
--apiserver-advertise-address=10.0.8.10 \
--image-repository registry.aliyuncs.com/google_containers \
--kubernetes-version v1.20.0 \
--service-cidr=10.96.0.0/12 \
--pod-network-cidr=10.244.0.0/16

# 使用 kubectl 工具（Master&&Node节点）
mkdir -p $HOME/.kube 
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config 
sudo chown $(id -u):$(id -g) $HOME/.kube/config

安装 Pod 网络插件（CNI）

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

Node节点加入集群

kubeadm join 10.0.8.10:6443 --token lv310b.ta2drrnxivb64ekb \
    --discovery-token-ca-cert-hash sha256:8f1d72b369a57143a6f3ba73eab1e8d8b90b887146a157cd277a4f37342f42fd

# 查看节点情况
kubectl get nodes

验证

# 测试 kubernetes 集群 在 Kubernetes 集群中创建一个 pod，验证是否正常运行：
kubectl create deployment nginx --image=nginx
kubectl expose deployment nginx --port=80 --type=NodePort
kubectl get pod,svc

NAME                         READY   STATUS    RESTARTS   AGE
pod/nginx-6799fc88d8-mbbg7   1/1     Running   0          3m3s

NAME                 TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)        AGE
service/kubernetes   ClusterIP   10.96.0.1       <none>        443/TCP        97m
service/nginx        NodePort    10.111.210.21   <none>        80:30868/TCP   2m57s

# 访问
http://<Master或对应Node IP>:30868

安装完k8s集群之后很可能会出现以下情况：

[root@k8s-master ~]# kubectl get cs
NAME                 STATUS      MESSAGE          ERROR
scheduler            Unhealthy   Get http://127.0.0.1:10251/healthz: dial tcp 127.0.0.1:10251: connect: connection refused
controller-manager   Unhealthy   Get http://127.0.0.1:10252/healthz: dial tcp 127.0.0.1:10252: connect: connection refused
etcd-0               Healthy     {"health":"true"}

出现这种情况是kube-controller-manager.yaml和kube-scheduler.yaml设置的默认端口是0，在文件中注释掉就可以了。（每台master节点都要执行操作）

vim /etc/kubernetes/manifests/kube-scheduler.yaml
- --port=0                  ## 注释掉这行
vim /etc/kubernetes/manifests/kube-controller-manager.yaml
- --port=0                  ## 注释掉这行
# 每台master重启kubelet
systemctl restart kubelet.service
# 再次查看状态
[root@k8s-master ~]# kubectl get cs
Warning: v1 ComponentStatus is deprecated in v1.19+
NAME                 STATUS    MESSAGE             ERROR
scheduler            Healthy   ok                  
controller-manager   Healthy   ok                  
etcd-0               Healthy   {"health":"true"}  

部署Ingress(Master节点)

cd /root && vim mandatory.yaml

apiVersion: v1
kind: Namespace
metadata:
  name: ingress-nginx

---

apiVersion: apps/v1
kind: Deployment
metadata:
  name: default-http-backend
  labels:
    app.kubernetes.io/name: default-http-backend
    app.kubernetes.io/part-of: ingress-nginx
  namespace: ingress-nginx
spec:
  replicas: 1
  selector:
    matchLabels:
      app.kubernetes.io/name: default-http-backend
      app.kubernetes.io/part-of: ingress-nginx
  template:
    metadata:
      labels:
        app.kubernetes.io/name: default-http-backend
        app.kubernetes.io/part-of: ingress-nginx
    spec:
      terminationGracePeriodSeconds: 60
      containers:
        - name: default-http-backend
          image: registry.cn-qingdao.aliyuncs.com/kubernetes_xingej/defaultbackend-amd64:1.5
          livenessProbe:
            httpGet:
              path: /healthz
              port: 8080
              scheme: HTTP
            initialDelaySeconds: 30
            timeoutSeconds: 5
          ports:
            - containerPort: 8080
          resources:
            limits:
              cpu: 10m
              memory: 20Mi
            requests:
              cpu: 10m
              memory: 20Mi

---
apiVersion: v1
kind: Service
metadata:
  name: default-http-backend
  namespace: ingress-nginx
  labels:
    app.kubernetes.io/name: default-http-backend
    app.kubernetes.io/part-of: ingress-nginx
spec:
  ports:
    - port: 80
      targetPort: 8080
  selector:
    app.kubernetes.io/name: default-http-backend
    app.kubernetes.io/part-of: ingress-nginx

---

kind: ConfigMap
apiVersion: v1
metadata:
  name: nginx-configuration
  namespace: ingress-nginx
  labels:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx

---

kind: ConfigMap
apiVersion: v1
metadata:
  name: tcp-services
  namespace: ingress-nginx
  labels:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx

---

kind: ConfigMap
apiVersion: v1
metadata:
  name: udp-services
  namespace: ingress-nginx
  labels:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx

---

apiVersion: v1
kind: ServiceAccount
metadata:
  name: nginx-ingress-serviceaccount
  namespace: ingress-nginx
  labels:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx

---
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: ClusterRole
metadata:
  name: nginx-ingress-clusterrole
  labels:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx
rules:
  - apiGroups:
      - ""
    resources:
      - configmaps
      - endpoints
      - nodes
      - pods
      - secrets
    verbs:
      - list
      - watch
  - apiGroups:
      - ""
    resources:
      - nodes
    verbs:
      - get
  - apiGroups:
      - ""
    resources:
      - services
    verbs:
      - get
      - list
      - watch
  - apiGroups:
      - "extensions"
    resources:
      - ingresses
    verbs:
      - get
      - list
      - watch
  - apiGroups:
      - ""
    resources:
      - events
    verbs:
      - create
      - patch
  - apiGroups:
      - "extensions"
    resources:
      - ingresses/status
    verbs:
      - update

---
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: Role
metadata:
  name: nginx-ingress-role
  namespace: ingress-nginx
  labels:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx
rules:
  - apiGroups:
      - ""
    resources:
      - configmaps
      - pods
      - secrets
      - namespaces
    verbs:
      - get
  - apiGroups:
      - ""
    resources:
      - configmaps
    resourceNames:
      - "ingress-controller-leader-nginx"
    verbs:
      - get
      - update
  - apiGroups:
      - ""
    resources:
      - configmaps
    verbs:
      - create
  - apiGroups:
      - ""
    resources:
      - endpoints
    verbs:
      - get

---
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: RoleBinding
metadata:
  name: nginx-ingress-role-nisa-binding
  namespace: ingress-nginx
  labels:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: Role
  name: nginx-ingress-role
subjects:
  - kind: ServiceAccount
    name: nginx-ingress-serviceaccount
    namespace: ingress-nginx

---
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: ClusterRoleBinding
metadata:
  name: nginx-ingress-clusterrole-nisa-binding
  labels:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: nginx-ingress-clusterrole
subjects:
  - kind: ServiceAccount
    name: nginx-ingress-serviceaccount
    namespace: ingress-nginx

---

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-ingress-controller
  namespace: ingress-nginx
  labels:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx
spec:
  replicas: 1
  selector:
    matchLabels:
      app.kubernetes.io/name: ingress-nginx
      app.kubernetes.io/part-of: ingress-nginx
  template:
    metadata:
      labels:
        app.kubernetes.io/name: ingress-nginx
        app.kubernetes.io/part-of: ingress-nginx
      annotations:
        prometheus.io/port: "10254"
        prometheus.io/scrape: "true"
    spec:
      serviceAccountName: nginx-ingress-serviceaccount
      containers:
        - name: nginx-ingress-controller
          image: quay.io/kubernetes-ingress-controller/nginx-ingress-controller:0.20.0
          args:
            - /nginx-ingress-controller
            - --default-backend-service=$(POD_NAMESPACE)/default-http-backend
            - --configmap=$(POD_NAMESPACE)/nginx-configuration
            - --tcp-services-configmap=$(POD_NAMESPACE)/tcp-services
            - --udp-services-configmap=$(POD_NAMESPACE)/udp-services
            - --publish-service=$(POD_NAMESPACE)/ingress-nginx
            - --annotations-prefix=nginx.ingress.kubernetes.io
          securityContext:
            capabilities:
              drop:
                - ALL
              add:
                - NET_BIND_SERVICE
            runAsUser: 33
          env:
            - name: POD_NAME
              valueFrom:
                fieldRef:
                  fieldPath: metadata.name
            - name: POD_NAMESPACE
              valueFrom:
                fieldRef:
                  fieldPath: metadata.namespace
          ports:
            - name: http
              containerPort: 80
            - name: https
              containerPort: 443
          livenessProbe:
            failureThreshold: 3
            httpGet:
              path: /healthz
              port: 10254
              scheme: HTTP
            initialDelaySeconds: 10
            periodSeconds: 10
            successThreshold: 1
            timeoutSeconds: 1
          readinessProbe:
            failureThreshold: 3
            httpGet:
              path: /healthz
              port: 10254
              scheme: HTTP
            periodSeconds: 10
            successThreshold: 1
            timeoutSeconds: 1

---

# 应用及验证
kubectl apply -f mandatory.yaml 
kubectl get pods -n ingress-nginx -o wide

# 编写Ingress配置文件
cd /root && vi service-nodeport.yml

apiVersion: v1
kind: Service
metadata:
  name: ingress-nginx
  namespace: ingress-nginx
  labels:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx
spec:
  type: NodePort
  ports:
    - name: http
      port: 80
      targetPort: 80
      protocol: TCP
      nodePort: 32080  #http
    - name: https
      port: 443
      targetPort: 443
      protocol: TCP
      nodePort: 32443  #https
  selector:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx

kubectl apply -f service-nodeport.yml 
kubectl get svc -n ingress-nginx

集群卸载清理

kubeadm reset -f
modprobe -r ipip
lsmod
rm -rf ~/.kube/
rm -rf /etc/kubernetes/
rm -rf /etc/systemd/system/kubelet.service.d
rm -rf /etc/systemd/system/kubelet.service
rm -rf /usr/bin/kube*
rm -rf /etc/cni
rm -rf /opt/cni
rm -rf /var/lib/etcd
rm -rf /var/etcd
yum clean all
yum remove kube*