Merge pull request #64601 from hzxuzhonghu/cm-dynamic-loglevel-set

Automatic merge from submit-queue. If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

Other components support set log level dynamically

**What this PR does / why we need it**:

#63777 introduced a way to set glog.logging.verbosity dynamically. 
We should enable this for all other components, which is specially useful in debugging. 


**Release note**:

```release-note
Expose `/debug/flags/v` to allow kubelet dynamically set glog logging level.  If want to change glog level to 3, you only have to send a PUT request like `curl -X PUT http://127.0.0.1:8080/debug/flags/v -d "3"`.
```

pkg/kubelet/server/BUILD

@@ -38,7 +38,9 @@ go_library(
         "//staging/src/k8s.io/apiserver/pkg/authorization/authorizer:go_default_library",
         "//staging/src/k8s.io/apiserver/pkg/server/healthz:go_default_library",
         "//staging/src/k8s.io/apiserver/pkg/server/httplog:go_default_library",
+        "//staging/src/k8s.io/apiserver/pkg/server/routes:go_default_library",
         "//staging/src/k8s.io/apiserver/pkg/util/flushwriter:go_default_library",
+        "//staging/src/k8s.io/apiserver/pkg/util/logs:go_default_library",
         "//vendor/github.com/emicklei/go-restful:go_default_library",
         "//vendor/github.com/golang/glog:go_default_library",
         "//vendor/github.com/google/cadvisor/info/v1:go_default_library",

pkg/kubelet/server/server.go

@@ -49,7 +49,9 @@ import (
 	"k8s.io/apiserver/pkg/authorization/authorizer"
 	"k8s.io/apiserver/pkg/server/healthz"
 	"k8s.io/apiserver/pkg/server/httplog"
+	"k8s.io/apiserver/pkg/server/routes"
 	"k8s.io/apiserver/pkg/util/flushwriter"
+	"k8s.io/apiserver/pkg/util/logs"
 	"k8s.io/kubernetes/pkg/api/legacyscheme"
 	api "k8s.io/kubernetes/pkg/apis/core"
 	"k8s.io/kubernetes/pkg/apis/core/v1/validation"
@@ -410,6 +412,10 @@ func (s *Server) InstallDebuggingHandlers(criHandler http.Handler) {
 	})).Doc("pprof endpoint")
 	s.restfulCont.Add(ws)
 
+	// Setup flags handlers.
+	// so far, only logging related endpoints are considered valid to add for these debug flags.
+	s.restfulCont.Handle("/debug/flags/v", routes.StringFlagPutHandler(logs.GlogSetter))
+
 	// The /runningpods endpoint is used for testing only.
 	ws = new(restful.WebService)
 	ws.

staging/src/k8s.io/apiserver/pkg/server/BUILD

@@ -101,6 +101,7 @@ go_library(
         "//staging/src/k8s.io/apiserver/pkg/server/routes:go_default_library",
         "//staging/src/k8s.io/apiserver/pkg/server/storage:go_default_library",
         "//staging/src/k8s.io/apiserver/pkg/util/feature:go_default_library",
+        "//staging/src/k8s.io/apiserver/pkg/util/logs:go_default_library",
         "//staging/src/k8s.io/client-go/informers:go_default_library",
         "//staging/src/k8s.io/client-go/rest:go_default_library",
         "//staging/src/k8s.io/client-go/util/cert:go_default_library",

staging/src/k8s.io/apiserver/pkg/server/config.go

@@ -60,6 +60,7 @@ import (
 	"k8s.io/apiserver/pkg/server/routes"
 	serverstore "k8s.io/apiserver/pkg/server/storage"
 	utilfeature "k8s.io/apiserver/pkg/util/feature"
+	"k8s.io/apiserver/pkg/util/logs"
 	"k8s.io/client-go/informers"
 	restclient "k8s.io/client-go/rest"
 	certutil "k8s.io/client-go/util/cert"
@@ -564,15 +565,7 @@ func installAPI(s *GenericAPIServer, c *Config) {
 			goruntime.SetBlockProfileRate(1)
 		}
 		// so far, only logging related endpoints are considered valid to add for these debug flags.
-		routes.DebugFlags{}.Install(s.Handler.NonGoRestfulMux, "v", routes.StringFlagPutHandler(
-			routes.StringFlagSetterFunc(func(val string) (string, error) {
-				var level glog.Level
-				if err := level.Set(val); err != nil {
-					return "", fmt.Errorf("failed set glog.logging.verbosity %s: %v", val, err)
-				}
-				return "successfully set glog.logging.verbosity to " + val, nil
-			}),
-		))
+		routes.DebugFlags{}.Install(s.Handler.NonGoRestfulMux, "v", routes.StringFlagPutHandler(logs.GlogSetter))
 	}
 	if c.EnableMetrics {
 		if c.EnableProfiling {

staging/src/k8s.io/apiserver/pkg/util/logs/logs.go

@@ -18,6 +18,7 @@ package logs
 
 import (
 	"flag"
+	"fmt"
 	"log"
 	"time"
 
@@ -67,3 +68,12 @@ func FlushLogs() {
 func NewLogger(prefix string) *log.Logger {
 	return log.New(GlogWriter{}, prefix, 0)
 }
+
+// GlogSetter is a setter to set glog level.
+func GlogSetter(val string) (string, error) {
+	var level glog.Level
+	if err := level.Set(val); err != nil {
+		return "", fmt.Errorf("failed set glog.logging.verbosity %s: %v", val, err)
+	}
+	return fmt.Sprintf("successfully set glog.logging.verbosity to %s", val), nil
+}