使用kubeadm方式快速部署一个K8S集群

目录

一、环境准备

二、环境初始化 

三、在所有主机上安装相关软件

1、安装docker

2、配置k8s的yum源

3、安装kubelet、kubeadm、kubectl

四、部署Kubernetes Master

五、加入Kubernets Node

六、部署CNI网络插件

七、测试k8s集群

---

一、环境准备

我的是CentOS7系统，然后准备三台虚拟主机

一台master，和两台node：node1、node2

我设置的主机名以及对应IP如下：

主机名	IP地址
k8smaster	192.168.198.150
k8snode1	192.168.198.151
k8snode2	192.168.198.152

二、环境初始化 

虚拟主机准备好之后，每一台都必须要关闭防火墙和selinux服务，以及关闭swap

在所有主机上执行：

#所有主机都要执行的操作

#关闭防火墙

临时：systemctl stop firewalld

永久：systemctl disable firewall

#关闭selinux

临时：setenforce 0

永久：sed -i 's/enforcing/disabled' /etc/selinux/config

#关闭swap

临时：swapoff -a

永久：sed -ri 's/.*swap.*/#&/' /etc/fstab

#开启流量转发，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

使其生效：sysctl --system

#设置时间同步

yum install ntpdate -y

ntp time.windows.com

仅在192.168.198.150（master）主机上执行：

#master上做的操作

#在master上添加hosts，根据自己设置的主机名和对应IP添加

cat >> /etc/hosts << EOF

192.168.198.150 k8smaster

192.168.198.151 k8snode1

192.168.198.152 k8snode2

EOF

三、在所有主机上安装相关软件

所有主机上执行以下所有安装操作

1、安装docker

#使用阿里云的提供的docker仓库

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

#更新yum缓存

yum clean all && yum makecache

#查看yum源中可用的版本

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

#直接yum安装

yum install -y docker-ce-20.10.6

#也可以直接安装旧版本

#yum install -y docker-ce-18.09.9

#启动docker，并设置开机自启

systemctl start docker
systemctl enable docker

#查看版本信息，能看到则安装启动成功

docker version

然后配置加速器，可以去登录自己的阿里云账号，获取容器镜像服务

点击链接：

阿里云登录 - 欢迎登录阿里云，安全稳定的云计算服务平台

复制步骤就可以完成了

2、配置k8s的yum源

#配置阿里的官方yum源，方便后面软件的安装

cat < /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
EOF

3、安装kubelet、kubeadm、kubectl

#由于版本更新频繁，所以我这里指定版本号部署，也可以不指定版本

yum install -y kubelet-1.19.4 kubeadm-1.19.4 kubectl-1.19.4

#设置开机自启

systemctl enable kubelet

四、部署Kubernetes Master

仅在主机192.168.198.150（master）上执行：

#执行命令初始化

kubeadm init    \

--apiserver-advertise-address=192.168.198.150    \     #写主机的IP

--image-repository registry.aliyuncs.com/google_containers    \     #指定为阿里云仓库地址

--kubernetes-version v1.19.4    \          #指定版本信息，和你安装的版本要一致

--service-cidr=10.88.0.0/12     \        #这个无所谓，只要不和其他的IP冲突即可

--pod-network-cidr=10.240.0.0/16          #同样的，不和其他IP冲突即可

#上面的斜杠\表示换行，方便展示命令，其实是一条完整命令，如下

kubeadm init --apiserver-advertise-address=192.168.198.150 --image-repository registry.aliyuncs.com/google_containers --kubernetes-version v1.19.4 --service-cidr=10.88.0.0/12 --pod-network-cidr=10.240.0.0/16

#然后就可以看到拉取到了这些镜像
[root@k8smaster ~]# docker images
REPOSITORY                                                        TAG        IMAGE ID       CREATED       SIZE
registry.aliyuncs.com/google_containers/kube-proxy                v1.19.4    635b36f4d89f   2 years ago   118MB
registry.aliyuncs.com/google_containers/kube-controller-manager   v1.19.4    4830ab618586   2 years ago   111MB
registry.aliyuncs.com/google_containers/kube-apiserver            v1.19.4    b15c6247777d   2 years ago   119MB
registry.aliyuncs.com/google_containers/kube-scheduler            v1.19.4    14cd22f7abe7   2 years ago   45.7MB
registry.aliyuncs.com/google_containers/etcd                      3.4.13-0   0369cf4303ff   2 years ago   253MB
registry.aliyuncs.com/google_containers/coredns                   1.7.0      bfe3a36ebd25   3 years ago   45.2MB
registry.aliyuncs.com/google_containers/pause                     3.2        80d28bedfe5d   3 years ago   683kB
[root@k8smaster ~]#

我们刚才在执行完kubeamd init命令之后，结尾会有以下信息

然后就可以直接复制这三条命令去执行

#执行以下命令即可使用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

五、加入Kubernets Node

仅在两个Node节点（node1、node2）上执行：

继续看到刚才在Master上执行完kubeamd init命令之后的结尾信息

#复制命令到Node节点：192.168.198.151（node1）和192.168.198.152（node2）上执行

kubeadm join 192.168.198.150:6443 --token pto6nc.ibvfrahbo8siq8rh \
    --discovery-token-ca-cert-hash sha256:485c64cd0b07b7c7aab9c95decd09b8bf2d4ab105c207d203767486d68f075a8

在Master上可以看到节点信息，k8snode1和k8snode2就被加入进来了

[root@k8smaster ~]# kubectl get nodes
NAME        STATUS     ROLES    AGE   VERSION
k8smaster   NotReady   master   21m   v1.19.4
k8snode1    NotReady      98s   v1.19.4
k8snode2    NotReady      88s   v1.19.4

#默认token有效期为24小时，过期后就不可用了，需要重新创建token可以执行以下命令

kubeadm token create --print-join-command

六、部署CNI网络插件

在192.168.198.150（master）上执行

#从docker hub上下载镜像仓库，由于是国外网站，可能会失败，多试几次

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

如果一直失败的话，可以试试以下办法：

vim kube-flannel.yml，然后复制下面代码框中的内容进去，保存退出之后，再执行kubectl apply -f kube-flannel.yml命令即可

---
kind: Namespace
apiVersion: v1
metadata:
  name: kube-flannel
  labels:
    k8s-app: flannel
    pod-security.kubernetes.io/enforce: privileged
---
kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  labels:
    k8s-app: flannel
  name: flannel
rules:
- apiGroups:
  - ""
  resources:
  - pods
  verbs:
  - get
- apiGroups:
  - ""
  resources:
  - nodes
  verbs:
  - get
  - list
  - watch
- apiGroups:
  - ""
  resources:
  - nodes/status
  verbs:
  - patch
- apiGroups:
  - networking.k8s.io
  resources:
  - clustercidrs
  verbs:
  - list
  - watch
---
kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  labels:
    k8s-app: flannel
  name: flannel
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: flannel
subjects:
- kind: ServiceAccount
  name: flannel
  namespace: kube-flannel
---
apiVersion: v1
kind: ServiceAccount
metadata:
  labels:
    k8s-app: flannel
  name: flannel
  namespace: kube-flannel
---
kind: ConfigMap
apiVersion: v1
metadata:
  name: kube-flannel-cfg
  namespace: kube-flannel
  labels:
    tier: node
    k8s-app: flannel
    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-flannel
  labels:
    tier: node
    app: flannel
    k8s-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: docker.io/flannel/flannel-cni-plugin:v1.2.0
        command:
        - cp
        args:
        - -f
        - /flannel
        - /opt/cni/bin/flannel
        volumeMounts:
        - name: cni-plugin
          mountPath: /opt/cni/bin
      - name: install-cni
        image: docker.io/flannel/flannel:v0.22.2
        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: docker.io/flannel/flannel:v0.22.2
        command:
        - /opt/bin/flanneld
        args:
        - --ip-masq
        - --kube-subnet-mgr
        resources:
          requests:
            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

#执行命令下载
[root@k8smaster ~]# kubectl apply -f kube-flannel.yml 
namespace/kube-flannel created
clusterrole.rbac.authorization.k8s.io/flannel created
clusterrolebinding.rbac.authorization.k8s.io/flannel created
serviceaccount/flannel created
configmap/kube-flannel-cfg created
daemonset.apps/kube-flannel-ds created
[root@k8smaster ~]# 

#然后再来查看status状态，还没好的多等一会儿就会好
[root@k8smaster ~]# kubectl get pods -n kube-system
NAME                                READY   STATUS    RESTARTS   AGE
coredns-6d56c8448f-82vp9            0/1     Pending   0          64m
coredns-6d56c8448f-vdlrw            0/1     Pending   0          64m
etcd-k8smaster                      1/1     Running   0          64m
kube-apiserver-k8smaster            1/1     Running   0          64m
kube-controller-manager-k8smaster   1/1     Running   0          64m
kube-proxy-89dm9                    1/1     Running   0          64m
kube-proxy-ltrtj                    1/1     Running   0          44m
kube-proxy-ngph4                    1/1     Running   0          44m
kube-scheduler-k8smaster            1/1     Running   0          64m

#查看nodes状态，都是Ready即可
[root@k8smaster ~]# kubectl get nodes
NAME        STATUS   ROLES    AGE   VERSION
k8smaster   Ready    master   91m   v1.19.4
k8snode1    Ready       71m   v1.19.4
k8snode2    Ready       71m   v1.19.4

七、测试k8s集群

在192.168.198.150（master）上执行

在Kubernetes集群中创建一个pod，验证是否正常运行

#拉取nginx镜像 
[root@k8smaster ~]# kubectl create deployment nginx --image=nginx
deployment.apps/nginx created

#等待状态变成running
[root@k8smaster ~]# kubectl get pod
NAME                     READY   STATUS              RESTARTS   AGE
nginx-6799fc88d8-s2pt9   0/1     ContainerCreating   0          67s

#设置对外暴露的端口，提供访问
[root@k8smaster ~]# kubectl expose deployment nginx --port=80 --type=NodePort
service/nginx exposed

#查看对外暴露的端口信息，因为我目前还没启动好，状态显示还在连网拉取当中
[root@k8smaster ~]# kubectl get pod,svc
NAME                         READY   STATUS              RESTARTS   AGE
pod/nginx-6799fc88d8-s2pt9   0/1     ContainerCreating   0          11m

NAME                 TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)        AGE
service/kubernetes   ClusterIP   10.80.0.1               443/TCP        109m
service/nginx        NodePort    10.81.133.109           80:32061/TCP   48s
[root@k8smaster ~]# 

##可以看到端口是80映射到32061

由于我的状态还在ContainerCreating中，很慢，泡的枸杞都喝完两杯了还没好（不知道是网速问题，还是设备资源给小了的问题），就没法演示了，等到状态是Running就可以测试了。测试的时候就可以用任意一个Node节点的IP，后面跟上刚查看到的32061这个端口，便可以访问到nginx的欢迎界面。