将自己的go应用部署到K8S

通过如下几步可以将自己的go应用部署到k8s上

1. 首先生成自己的go项目

   mkdir src
   cd src
   go mod init servertest

2. 编写测试代码main.go内容如下，很简单

   package main
   
   import (
           "github.com/gin-gonic/gin"
           "fmt"
           "time"
           "net/http"
   )
   
   type getTimeResp struct {
           CTime string
   }
   
   func getTimeHandler(ctx *gin.Context) {
           content := fmt.Sprintf("%d", time.Now().Nanosecond())
           fmt.Printf("%s\n", content)
           resp := &getTimeResp{
                   CTime:content,
           }
   
           ctx.JSON(http.StatusOK, resp)
   }
   
   
   func main() {
           r := gin.Default()
           r.GET("/gettime", getTimeHandler)
   
           r.Run(":8000")
   }

3. 编写Dockerfile内容如下

   FROM golang:1.17.1-alpine as builder
   ENV GOPROXY=https://goproxy.cn
   WORKDIR /build
   COPY ./src .
   RUN mkdir /app
   RUN go mod tidy
   RUN go build 
   
   FROM  alpine:latest
   RUN mkdir -p /cmd
   WORKDIR  /cmd
   COPY  --from=builder /build/servertest  .
   EXPOSE 8000
   CMD ["./servertest"]

4. 生成镜像，执行命令

   docker build -t servertest:1.0.0 -f Dockerfile .

   执行

   docker images

   可以看到生成的servertest:1.0.0镜像已经存在了

   因为k8s集群会存在多个nod所以多个nod都需要拉取镜像，所以需要保自己的镜像推到镜像服务器，我这里选用阿里的。
   先登陆->将自己生成的镜像打tag->推到镜像服务器

   docker login --username=your_loginname_xxxx registry.cn-shanghai.aliyuncs.com
   docker tag servertest:1.0.0 registry.cn-shanghai.aliyuncs.com/your_hubname_xxxx/servertest:1.0.0
   docker push registry.cn-shanghai.aliyuncs.com/your_hubname_xxxx/servertest:1.0.0

5. 编写deployment和service配置文件
   deployment.yaml文件内容如下

   apiVersion: apps/v1
   kind: Deployment
   metadata:
     name: my-go-app
   spec:
     replicas: 3
     selector:
       matchLabels:
         app: my-go-app
     template:
       metadata:
         labels:
           app: my-go-app
       spec:
         containers:
           - name: go-app-container
             image: registry.cn-shanghai.aliyuncs.com/your_hubname_xxxx/servertest:1.0.0
             imagePullPolicy: IfNotPresent
             resources:
               limits:
                 memory: "512Mi"
                 cpu: "500m"
               requests:
                 memory: "64Mi"
                 cpu: "100m"
             ports:
             - containerPort: 8000

   service.yaml内容如下

   apiVersion: v1
   kind: Service
   metadata:
     name: servertest-service
   spec:
     type: NodePort
     ports:
       - port: 8000
         nodePort: 30066
     selector:
       app: my-go-app

   需要对外提供服务所以type选NodePort
   port：8000是对应pod的端口号
   nodePort：30066是service对外提供的调用端口号

6. 部署
   执行

   kubectl create -f ./yaml/deployment.yaml
   kubectl create -f ./yaml/service.yaml

   查看pod和service状况

   kubectl get pod,svc -n default

   可以看到如下
   

   三个pod(my-go-app-xxxxxx-xxxx)处在Running状态
   service的Port30066对外提供服务

7. 访问确认
   查看任何一个node的物理IP地址，通过访问node主机的IP：30066/gettime
   会返回当前时间（nano second）