手摸手教你写 Kubernetes 的 golang 服务

kuberneteskubernetesgolang

golang

对于 golang 的安装和配置，我们这里就不详细说明了，因为这也不是我们的重点，我相信这一步你是能够自己独立完成的。

golang

新建项目文件夹goappk8s，然后在该目录下面新建一个src目录

$ mkdir goappk8s && cd goappk8s
$ mkdir src

GOPATHsetup-gopath.sh

#!/bin/bash
DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
export GOPATH="$DIR"

GOPATH

$ source setup-gopath.sh
$ echo $GOPATH
/Users/ych/devs/workspace/yidianzhishi/goappk8s

GOPATH

$ mkdir -p github.com/cnych/goappk8s && cd github.com/cnych/goappk8s
$ touch main.go

golang

package main

import (
    "github.com/gin-gonic/gin"
    "net/http"
)

func main() {
    router := gin.Default()
    router.GET("/ping", func(c *gin.Context) {
        c.String(http.StatusOK, "PONG")
    })
    router.Run(":8080")
}

github.com/gin-gonic/ginGOPATHgovendorgithub.com/cnych/goappk8s

$ govendor init
$ govendor fetch github.com/gin-gonic/gin

注意上面的包需要拉取一些墙外的包。

GOPATH

$ go install github.com/cnych/goappk8s && ./bin/goappk8s
[GIN-debug] [WARNING] Creating an Engine instance with the Logger and Recovery middleware already attached.

[GIN-debug] [WARNING] Running in "debug" mode. Switch to "release" mode in production.
 - using env:   export GIN_MODE=release
 - using code:  gin.SetMode(gin.ReleaseMode)

[GIN-debug] GET    /ping                     --> main.main.func1 (3 handlers)
[GIN-debug] Listening and serving HTTP on :8080

golangPONG

Docker

golangDockerfile

FROM golang AS build-env
ADD . /go/src/app
WORKDIR /go/src/app
RUN go get -u -v github.com/kardianos/govendor
RUN govendor sync
RUN GOOS=linux GOARCH=386 go build -v -o /go/src/app/app-server

FROM alpine
RUN apk add -U tzdata
RUN ln -sf /usr/share/zoneinfo/Asia/Shanghai  /etc/localtime
COPY --from=build-env /go/src/app/app-server /usr/local/bin/app-server
EXPOSE 8080
CMD [ "app-server" ]

Docker

$ docker build -t cnych/goappk8s:v1.0.0 .
.......(省略了)
Successfully built 00751f94d8a9
Successfully tagged cnych/goappk8s:v1.0.0
$ docker push cnych/goappk8s:v1.0.0

cnych/goappk8s:v1.0.0dockerhub

kubernetes

Kubernetes

kubernetesDockerfilekubernetes

---
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: goapp-deploy
  namespace: kube-apps
  labels:
    k8s-app: goappk8s
spec:
  replicas: 2
  revisionHistoryLimit: 10
  minReadySeconds: 5
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxSurge: 1
      maxUnavailable: 1
  template:
    metadata:
      labels:
        k8s-app: goappk8s
    spec:
      containers:
      - image: cnych/goappk8s:v1.0.0
        imagePullPolicy: Always
        name: goappk8s
        ports:
        - containerPort: 8080
          protocol: TCP
        resources:
          limits:
            cpu: 100m
            memory: 100Mi
          requests:
            cpu: 50m
            memory: 50Mi
        livenessProbe:
          tcpSocket:
            port: 8080
          initialDelaySeconds: 10
          timeoutSeconds: 3
        readinessProbe:
          httpGet:
            path: /ping
            port: 8080
          initialDelaySeconds: 10
          timeoutSeconds: 2

---
apiVersion: v1
kind: Service
metadata:
  name: goapp-svc
  namespace: kube-apps
  labels:
    k8s-app: goappk8s
spec:
  ports:
    - name: api
      port: 8080
      protocol: TCP
      targetPort: 8080
  selector:
    k8s-app: goappk8s

---
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: goapp-ingress
  namespace: kube-apps
spec:
  rules:
  - host: goappk8s.local
    http:
      paths:
      - path: /
        backend:
          serviceName: goapp-svc
          servicePort: api

k8s.yamlDeploymentServiceIngressYAMLreplicas: 2PODstrategyRollingUpdateresourcesPODlivenessProbereadinessProbekubectl

$ kubectl apply -f k8s.yaml
deployment "goapp-deploy" created
service "goapp-svc" created
ingress "goapp-ingress" created

我们可以看到上面定义的三种资源都创建成功了。然后查看资源状态：

$ kubectl get deployments -n kube-apps |grep goapp
goapp-deploy     2         2         2            2           57s
$ kubectl get svc -n kube-apps |grep goapp
goapp-svc      ClusterIP   10.254.109.69    <none>        8080/TCP                         1m
$ kubectl get ingress -n kube-apps |grep goapp
goapp-ingress   goappk8s.local              80        1m
$ kubectl get pods -n kube-apps |grep goapp
goapp-deploy-84bb6979c-59qkl                             1/1       Running   0          2m
goapp-deploy-84bb6979c-mgg2r                             1/1       Running   0          2m

kubernetesPOD/etc/hostsIngress

你的k8s集群节点IP goappk8s.local

然后我们在浏览器中访问链接http://goappk8s.local/ping，可以看到页面上已经打印出来PONG。

最后整理下代码，将我们的代码提交到github去吧。

CI/CDkubernetes

k8s技术圈