k8s APIServer源码: 服务启动
基于版本 1.6.7
启动流程
- cmd/kube-apiserver/apiserver.go
func main() {
app.Run(s)
}
- cmd/kube-apiserver/app/server.go
func Run(s *options.ServerRunOptions) error {
// 构建master配置信息
config, sharedInformers, err := BuildMasterConfig(s)
// 调用RunServer
return RunServer(config, sharedInformers, wait.NeverStop)
}
func RunServer(config *master.Config, sharedInformers informers.SharedInformerFactory, stopCh <-chan struct{}) error {
// 执行相关初始化
m, err := config.Complete().New() // => TO: Container初始化
// 启动
return m.GenericAPIServer.PrepareRun().Run(stopCh) // => next
}
- vendor/k8s.io/apiserver/pkg/server/genericapiserver.go
启动主体函数都在这个文件中, 绑定地址/端口号, 并最终启动
func (s preparedGenericAPIServer) Run(stopCh <-chan struct{}) error {
s.NonBlockingRun(stopCh)
}
func (s preparedGenericAPIServer) NonBlockingRun(stopCh <-chan struct{}) error {
s.serveSecurely(internalStopCh)
// or
s.serveInsecurely(internalStopCh) // => next
}
- vendor/k8s.io/apiserver/pkg/server/serve.go
func (s *GenericAPIServer) serveInsecurely(stopCh <-chan struct{}) error {
insecureServer := &http.Server{
Addr: s.InsecureServingInfo.BindAddress,
Handler: s.InsecureHandler, // s.Hnalder for secure
MaxHeaderBytes: 1 << 20,
}
runServer(insecureServer, s.InsecureServingInfo.BindNetwork, stopCh) // => next
}
func runServer(server *http.Server, network string, stopCh <-chan struct{}) (int, error) {
go func() {
for {
var listener net.Listener
listener = tcpKeepAliveListener{ln.(*net.TCPListener)}
// *http.Server
err := server.Serve(listener)
}
}()
}
Container初始化
- cmd/kube-apiserver/app/server.go
func RunServer(config *master.Config, sharedInformers informers.SharedInformerFactory, stopCh <-chan struct{}) error {
// 执行相关初始化
m, err := config.Complete().New() // => TO: Container初始化
// 启动
return m.GenericAPIServer.PrepareRun().Run(stopCh) // => next
}
- kubernetes/pkg/master/master.go
func (c completedConfig) New() (*Master, error) {
// m.GenericAPIServer.HandlerContainer = APIContainer, APIContainer.Container = restful.NewContainer()
s, err := c.Config.GenericConfig.SkipComplete().New() // completion is done in Complete, no need for a second time
m := &Master{
GenericAPIServer: s,
}
}
- vendor/k8s.io/apiserver/pkg/server/config.go
到这里, 完成了 s.Handler, s.InsecureHandler 的初始化
func (c completedConfig) New() (*GenericAPIServer, error) {
s := &GenericAPIServer{
}
// s.HandlerContainer = APIContainer
s.HandlerContainer = mux.NewAPIContainer(http.NewServeMux(), c.Serializer) // => next 1
// 生成 Handler
s.Handler, s.InsecureHandler = c.BuildHandlerChainsFunc(s.HandlerContainer.ServeMux, c.Config) // => next 2
}
- 1: vendor/k8s.io/apiserver/pkg/server/mux/container.go
新建一个APIContainer, 包含
// NewAPIContainer constructs a new container for APIs
func NewAPIContainer(mux *http.ServeMux, s runtime.NegotiatedSerializer) *APIContainer {
c := APIContainer{
// 新建一个Container
Container: restful.NewContainer(),
NonSwaggerRoutes: PathRecorderMux{
mux: mux,
},
UnlistedRoutes: mux,
}
// 配置 http.ServerMux
c.Container.ServeMux = mux
// 配置路由方式, 使用CurlyRouter
c.Container.Router(restful.CurlyRouter{}) // e.g. for proxy/{kind}/{name}/{*}
return &c
}
- 2: vendor/k8s.io/apiserver/pkg/server/config.go
type Config struct {
BuildHandlerChainsFunc func(apiHandler http.Handler, c *Config) (secure, insecure http.Handler)
}
func NewConfig() *Config {
return &Config{
BuildHandlerChainsFunc: DefaultBuildHandlerChain,
}
}
func DefaultBuildHandlerChain(apiHandler http.Handler, c *Config) (secure, insecure http.Handler) {
return generic(protect(apiHandler)), generic(audit(apiHandler)) // add filters to handler
}
注意, 这里传递的参数是: s.HandlerContainer.ServeMux, DefaultBuildHandlerChain的参数是apiHandler http.Handler, 前者包含后者interface定义的方法.
- net/http/server.go
type Handler interface {
ServeHTTP(ResponseWriter, *Request)
}
// ServeHTTP dispatches the request to the handler whose
// pattern most closely matches the request URL.
func (mux *ServeMux) ServeHTTP(w ResponseWriter, r *Request) {
if r.RequestURI == "*" {
if r.ProtoAtLeast(1, 1) {
w.Header().Set("Connection", "close")
}
w.WriteHeader(StatusBadRequest)
return
}
h, _ := mux.Handler(r)
h.ServeHTTP(w, r)
}
初始化后, Hnalder 以及 InsecureHandler赋值Container, 然后在new Server前, 将handler放入
&http.Server{
Addr: s.InsecureServingInfo.BindAddress,
Handler: s.InsecureHandler, // s.Hanlder for secure
MaxHeaderBytes: 1 << 20,
}