support dump scheduler cache snapshot to json file

Signed-off-by: lowang-bh <lhui_wang@163.com>

cmd/scheduler/app/options/options.go

@@ -77,10 +77,12 @@ type ServerOption struct {
 	PercentageOfNodesToFind    int32
 
 	NodeSelector      []string
+	CacheDumpFileDir  string
 	EnableCacheDumper bool
 	NodeWorkerThreads uint32
 }
 
+// DecryptFunc is custom function to parse ca file
 type DecryptFunc func(c *ServerOption) error
 
 // ServerOpts server options.
@@ -133,6 +135,7 @@ func (s *ServerOption) AddFlags(fs *pflag.FlagSet) {
 	fs.BoolVar(&s.EnableMetrics, "enable-metrics", false, "Enable the metrics function; it is false by default")
 	fs.StringSliceVar(&s.NodeSelector, "node-selector", nil, "volcano only work with the labeled node, like: --node-selector=volcano.sh/role:train --node-selector=volcano.sh/role:serving")
 	fs.BoolVar(&s.EnableCacheDumper, "cache-dumper", true, "Enable the cache dumper, it's true by default")
+	fs.StringVar(&s.CacheDumpFileDir, "cache-dump-dir", "/tmp", "The target dir where the json file put at when dump cache info to json file")
 	fs.Uint32Var(&s.NodeWorkerThreads, "node-worker-threads", defaultNodeWorkers, "The number of threads syncing node operations.")
 }
 

cmd/scheduler/app/options/options_test.go

@@ -58,6 +58,7 @@ func TestAddFlags(t *testing.T) {
 		EnableLeaderElection:       true,
 		LockObjectNamespace:        defaultLockObjectNamespace,
 		NodeWorkerThreads:          defaultNodeWorkers,
+		CacheDumpFileDir:           "/tmp",
 	}
 
 	if !reflect.DeepEqual(expected, s) {

pkg/scheduler/cache/dumper.go

@@ -17,11 +17,15 @@
 package cache
 
 import (
+	"encoding/json"
+	"fmt"
 	"os"
 	"os/signal"
+	"path"
 	"runtime"
 	"strings"
 	"syscall"
+	"time"
 
 	"k8s.io/klog/v2"
 
@@ -32,9 +36,31 @@ import (
 // for debugging purposes. Usage: run `kill -s USR2 <pid>` in the shell, where <pid>
 // is the process id of the scheduler process.
 type Dumper struct {
-	Cache Cache
+	Cache   Cache
+	RootDir string // target directory for the dumped json file
 }
 
+// dumpToJSONFile marsh scheduler cache snapshot to json file
+func (d *Dumper) dumpToJSONFile() {
+	snapshot := d.Cache.Snapshot()
+	name := fmt.Sprintf("snapshot-%d.json", time.Now().Unix())
+	fName := path.Join(d.RootDir, name)
+	file, err := os.OpenFile(fName, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0644)
+	if err != nil {
+		klog.Errorf("error creating snapshot because of error creating file: %v", err)
+		return
+	}
+	defer file.Close()
+	klog.Infoln("Starting to dump info in scheduler cache to file", fName)
+	if err = json.NewEncoder(file).Encode(snapshot.Nodes); err != nil {
+		klog.Errorf("Failed to dump info in scheduler cache, json encode error: %v", err)
+		return
+	}
+
+	klog.Infoln("Successfully dump info in scheduler cache to file", fName)
+}
+
+// dumpAll prints all information to log
 func (d *Dumper) dumpAll() {
 	snapshot := d.Cache.Snapshot()
 	klog.Info("Dump of nodes info in scheduler cache")
@@ -73,16 +99,20 @@ func (d *Dumper) printJobInfo(jobInfo *api.JobInfo) string {
 }
 
 // ListenForSignal starts a goroutine that will respond when process
-// receives SIGUSER2 signal.
+// receives SIGUSER1/SIGUSER2 signal.
 func (d *Dumper) ListenForSignal(stopCh <-chan struct{}) {
-	ch := make(chan os.Signal, 1)
-	signal.Notify(ch, syscall.SIGUSR2)
+	ch1 := make(chan os.Signal, 1)
+	ch2 := make(chan os.Signal, 1)
+	signal.Notify(ch1, syscall.SIGUSR1)
+	signal.Notify(ch2, syscall.SIGUSR2)
 	go func() {
 		for {
 			select {
 			case <-stopCh:
 				return
-			case <-ch:
+			case <-ch1:
+				d.dumpToJSONFile()
+			case <-ch2:
 				d.dumpAll()
 			}
 		}

pkg/scheduler/scheduler.go

@@ -74,7 +74,7 @@ func NewScheduler(config *rest.Config, opt *options.ServerOption) (*Scheduler, e
 		fileWatcher:    watcher,
 		cache:          cache,
 		schedulePeriod: opt.SchedulePeriod,
-		dumper:         schedcache.Dumper{Cache: cache},
+		dumper:         schedcache.Dumper{Cache: cache, RootDir: opt.CacheDumpFileDir},
 	}
 
 	return scheduler, nil