製作自己的docker鏡像併發布到k8s

本篇主要講述如何將自己的程序生成docker鏡像，並且發佈到k8s環境的簡單步驟。在這之前你需要了解基本的docker使用，基本的k8s概念和命令。

• Step1 編寫代碼
  爲了方便使用之前一篇的代碼，將KV值put到ETC集羣。具體代碼如下：

  package main
  
  import (
      "fmt"
      "io/ioutil"
      "log"
      "time"
  
      "crypto/tls"
      "crypto/x509"
  
      "go.etcd.io/etcd/clientv3"
      "golang.org/x/net/context"
  )
  
  var (
      dialTimeout    = 5 * time.Second
      requestTimeout = 4 * time.Second
      endpoints      = []string{"https://172.17.84.204:2379", "https://172.17.84.205:2379", "https://172.17.84.206:2379"}
  )
  
  func main() {
  
      log.Println("----Start running-----------")
      var etcdCert = "../ca/etcd-client.pem"
      var etcdCertKey = "../ca/etcd-client-key.pem"
      var etcdCa = "../ca/ca.pem"
  
      cert, err := tls.LoadX509KeyPair(etcdCert, etcdCertKey)
      if err != nil {
          log.Fatal("LoadX509KeyPair failed")
          return
      }
  
      caData, err := ioutil.ReadFile(etcdCa)
      if err != nil {
          log.Fatal("ReadFile(etcdCa) failed")
          return
      }
  
      pool := x509.NewCertPool()
      pool.AppendCertsFromPEM(caData)
  
      _tlsConfig := &tls.Config{
          Certificates: []tls.Certificate{cert},
          RootCAs:      pool,
      }
  
      cfg := clientv3.Config{
          Endpoints: endpoints,
          TLS:       _tlsConfig,
      }
  
      cli, err := clientv3.New(cfg)
  
      if err != nil {
          log.Fatal(err)
      }
  
      defer cli.Close()
  
      done := make(chan bool)
  
      key1 := "testkey1"
  
      go func() {
          log.Println("----Start putting value-----------")
          for cnt := 0; cnt < 65535; cnt++ {
              log.Println(cnt)
              value := fmt.Sprintf("%s%d", "value", cnt)
              _, err = cli.Put(context.Background(), key1, value)
              if err != nil {
                  log.Println("Put failed. ", err)
              } else {
                  log.Printf("Put {%s:%s} succeed\n", key1, value)
              }
          }
          done <- true
      }()
  
      <-done
  
      log.Println("Done!")
  }
  

  編譯代碼生成在Linux下的可執行文件

  GOOS=linux GOARCH=amd64 go build

• Step2 編寫Dockerfile

  FROM alpine:latest
  RUN mkdir /app
  RUN mkdir /ca
  WORKDIR /app
  ADD ./putvalue /app/putvalue
  CMD ["./putvalue"]

• Step3 生成Docker鏡像
  爲了方便直接將生成的鏡像發到docker hub。請自己去註冊https://hub.docker.com

  （1）執行docker login登陸

  （2）在Dockerfile目錄下執行命令生成docker鏡像

  docker build -t etcdpvimg .

  如果build成功會顯示如下信息
  

  （3）打tag，推送到docker hub
  執行命令對生成的鏡像打tag

  docker tag etcdpvimg your_account_xxx/etcdpvimg:latest

  push鏡像到docker hub

  docker push your_account_xxx/etcdpvimg:latest

• Step4 編寫K8s Deployment部署文件
  因爲訪問ETC需要使用證書，所以使用hosPath在Pod上掛載宿主機上的文件目錄

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: etcd-put-deployment
spec:
  replicas: 2
  selector:
    matchLabels:
      app: etcd-putvalue
  template:
    metadata:
      labels:
        app: etcd-putvalue
    spec:
      volumes:
        - name: cavol
          hostPath:
            path: "/ca"
      containers:
        - name: putvalue-test
          image: your_account_xxx/etcdpvimg:latest
          imagePullPolicy: IfNotPresent
          volumeMounts:
            - mountPath: /root/app/ca
              name: cavol

• Step5 發佈測試

  執行K8s的apply命令

  kubectl apply -f etcd-test-deployment.yml