接下来可以写main.go了，不过在此之前把处理系统信号量的辅助类先写好，然后在main.go中会用到（处理例如ctrl+c的退出），在$GOPATH/src/k8s_customize_controller/pkg目录下新建目录signals；
在signals目录下新建文件signal_posix.go：
// +build !windows package signals import ( "os" "syscall" ) var shutdownSignals = []os.Signal{os.Interrupt, syscall.SIGTERM}
在signals目录下新建文件signal_windows.go
package signals import ( "os" ) var shutdownSignals = []os.Signal{os.Interrupt}
在signals目录下新建文件signal.go
package signals import ( "os" "os/signal" ) var onlyOneSignalHandler = make(chan struct{}) func SetupSignalHandler() (stopCh <-chan struct{}) { close(onlyOneSignalHandler) // panics when called twice stop := make(chan struct{}) c := make(chan os.Signal, 2) signal.Notify(c, shutdownSignals...) go func() { <-c close(stop) <-c os.Exit(1) // second signal. Exit directly. }() return stop }
接下来可以编写main.go了，在k8s_customize_controller目录下创建main.go文件，内容如下，关键位置已经加了注释，就不再赘述了：
package main import ( "flag" "time" "github.com/golang/glog" "k8s.io/client-go/kubernetes" "k8s.io/client-go/tools/clientcmd" // Uncomment the following line to load the gcp plugin (only required to authenticate against GKE clusters). // _ "k8s.io/client-go/plugin/pkg/client/auth/gcp" clientset "k8s_customize_controller/pkg/client/clientset/versioned" informers "k8s_customize_controller/pkg/client/informers/externalversions" "k8s_customize_controller/pkg/signals" ) var ( masterURL string kubeconfig string ) func main() { flag.Parse() // 处理信号量 stopCh := signals.SetupSignalHandler() // 处理入参 cfg, err := clientcmd.BuildConfigFromFlags(masterURL, kubeconfig) if err != nil { glog.Fatalf("Error building kubeconfig: %s", err.Error()) } kubeClient, err := kubernetes.NewForConfig(cfg) if err != nil { glog.Fatalf("Error building kubernetes clientset: %s", err.Error()) } studentClient, err := clientset.NewForConfig(cfg) if err != nil { glog.Fatalf("Error building example clientset: %s", err.Error()) } studentInformerFactory := informers.NewSharedInformerFactory(studentClient, time.Second*30) //得到controller controller := NewController(kubeClient, studentClient, studentInformerFactory.Bolingcavalry().V1().Students()) //启动informer go studentInformerFactory.Start(stopCh) //controller开始处理消息 if err = controller.Run(2, stopCh); err != nil { glog.Fatalf("Error running controller: %s", err.Error()) } } func init() { flag.StringVar(&kubeconfig, "kubeconfig", "", "Path to a kubeconfig. Only required if out-of-cluster.") flag.StringVar(&masterURL, "master", "", "The address of the Kubernetes API server. Overrides any value in kubeconfig. Only required if out-of-cluster.") }至此，所有代码已经编写完毕，接下来是编译构建
编译构建和启动
在$GOPATH/src/k8s_customize_controller目录下，执行以下命令：
go get k8s.io/client-go/kubernetes/scheme \ && go get github.com/golang/glog \ && go get k8s.io/kube-openapi/pkg/util/proto \ && go get k8s.io/utils/buffer \ && go get k8s.io/utils/integer \ && go get k8s.io/utils/trace
上述脚本将编译过程中依赖的库通过go get方式进行获取，属于笨办法，更好的方法是选用一种包依赖工具，具体的可以参照k8s的官方demo，这个代码中同时提供了godep和vendor两种方式来处理上面的包依赖问题，地址是：https
解决了包依赖问题后，在$GOPATH/src/k8s_customize_controller目录下执行命令go build，即可在当前目录生成k8s_customize_controller文件；
将文件k8s_customize_controller复制到k8s环境中，记得通过chmod a+x命令给其可执行权限；
执行命令./k8s_customize_controller -kubeconfig=$HOME/.kube/config -alsologtostderr=true，会立即启动controller
总结现在小结一下自定义controller开发的整个过程：
创建CRD（Custom Resource Definition），令k8s明白我们自定义的API对象；
编写代码，将CRD的情况写入对应的代码中，然后通过自动代码生成工具，将controller之外的informer，client等内容较为固定的代码通过工具生成；
编写controller，在里面判断实际情况是否达到了API对象的声明情况，如果未达到，就要进行实际业务处理，而这也是controller的通用做法；