ingress-controller 源码分析

主要逻辑

nginx controller 入口函数

// file:k8s.io/ingress-nginx/nginx/main.go
func main() {
    // step1: 初始化日志组件
    klog.InitFlags(nil)

      ......

    // step2:创建必要的目录
    err = file.CreateRequiredDirectories()
      ......

    // step 3 :初始化ApiserverClient
    kubeClient, err := createApiserverClient(conf.APIServerHost, conf.RootCAFile, conf.KubeConfigFile)
      ......

    // step4: 检查service配置
    if len(conf.DefaultService) > 0 {
        err := checkService(conf.DefaultService, kubeClient)
          ......

        klog.Infof("Validated %v as the default backend.", conf.DefaultService)
    }

    if len(conf.PublishService) > 0 {
        err := checkService(conf.PublishService, kubeClient)
          ......
    }

    // step5:获取namespace
    if conf.Namespace != "" {
        _, err = kubeClient.CoreV1().Namespaces().Get(context.TODO(), conf.Namespace, metav1.GetOptions{})
        if err != nil {
            klog.Fatalf("No namespace with name %v found: %v", conf.Namespace, err)
        }
    }

    // step6: 创建默认证书
    conf.FakeCertificate = ssl.GetFakeSSLCert()
    klog.Infof("SSL fake certificate created %v", conf.FakeCertificate.PemFileName)

    // step7: 检查是否支持v1beta API 、k8s 版本是否高于1.18.0
    k8s.IsNetworkingIngressAvailable, k8s.IsIngressV1Ready = k8s.NetworkingIngressAvailable(kubeClient)
    if !k8s.IsNetworkingIngressAvailable {
        klog.Warningf("Using deprecated \"k8s.io/api/extensions/v1beta1\" package because Kubernetes version is < v1.14.0")
    }

    if k8s.IsIngressV1Ready {
          ......
    }

    conf.Client = kubeClient

    // step8: 注册prometheus
    reg := prometheus.NewRegistry()

    reg.MustRegister(prometheus.NewGoCollector())
    reg.MustRegister(prometheus.NewProcessCollector(prometheus.ProcessCollectorOpts{
        PidFn:        func() (int, error) { return os.Getpid(), nil },
        ReportErrors: true,
    }))
    ......

    // step9:启动profile
    if conf.EnableProfiling {
        go registerProfiler()
    }

    // step10: 实例化nginxcontroller （*）
    ngx := controller.NewNGINXController(conf, mc)

    // step11: 启动健康探测和metrics API
    mux := http.NewServeMux()
    registerHealthz(nginx.HealthPath, ngx, mux)
    registerMetrics(reg, mux)

    go startHTTPServer(conf.ListenPorts.Health, mux)

    // step12: 启动nginx master进程
    go ngx.Start()
  ......
}
// file:k8s.io