karmada/cmd/scheduler-estimator/app/scheduler-estimator.go

130 lines
4.0 KiB
Go

package app
import (
"context"
"fmt"
"net"
"net/http"
"os"
"strconv"
"time"
"github.com/prometheus/client_golang/prometheus/promhttp"
"github.com/spf13/cobra"
"k8s.io/client-go/discovery"
"k8s.io/client-go/dynamic"
"k8s.io/client-go/kubernetes"
"k8s.io/client-go/tools/clientcmd"
cliflag "k8s.io/component-base/cli/flag"
"k8s.io/component-base/term"
"k8s.io/klog/v2"
ctrlmetrics "sigs.k8s.io/controller-runtime/pkg/metrics"
"github.com/karmada-io/karmada/cmd/scheduler-estimator/app/options"
"github.com/karmada-io/karmada/pkg/estimator/server"
"github.com/karmada-io/karmada/pkg/sharedcli"
"github.com/karmada-io/karmada/pkg/sharedcli/klogflag"
"github.com/karmada-io/karmada/pkg/sharedcli/profileflag"
"github.com/karmada-io/karmada/pkg/version"
"github.com/karmada-io/karmada/pkg/version/sharedcommand"
)
const (
// ReadHeaderTimeout is the amount of time allowed to read
// request headers.
// HTTP timeouts are necessary to expire inactive connections
// and failing to do so might make the application vulnerable
// to attacks like slowloris which work by sending data very slow,
// which in case of no timeout will keep the connection active
// eventually leading to a denial-of-service (DoS) attack.
// References:
// - https://en.wikipedia.org/wiki/Slowloris_(computer_security)
ReadHeaderTimeout = 32 * time.Second
)
// NewSchedulerEstimatorCommand creates a *cobra.Command object with default parameters
func NewSchedulerEstimatorCommand(ctx context.Context) *cobra.Command {
opts := options.NewOptions()
cmd := &cobra.Command{
Use: "karmada-scheduler-estimator",
Long: `The karmada-scheduler-estimator runs an accurate scheduler estimator of a cluster. It
provides the scheduler with more accurate cluster resource information.`,
RunE: func(cmd *cobra.Command, args []string) error {
// validate options
if errs := opts.Validate(); len(errs) != 0 {
return errs.ToAggregate()
}
if err := run(ctx, opts); err != nil {
return err
}
return nil
},
}
fss := cliflag.NamedFlagSets{}
genericFlagSet := fss.FlagSet("generic")
opts.AddFlags(genericFlagSet)
// Set klog flags
logsFlagSet := fss.FlagSet("logs")
klogflag.Add(logsFlagSet)
cmd.AddCommand(sharedcommand.NewCmdVersion("karmada-scheduler-estimator"))
cmd.Flags().AddFlagSet(genericFlagSet)
cmd.Flags().AddFlagSet(logsFlagSet)
cols, _, _ := term.TerminalSize(cmd.OutOrStdout())
sharedcli.SetUsageAndHelpFunc(cmd, fss, cols)
return cmd
}
func run(ctx context.Context, opts *options.Options) error {
klog.Infof("karmada-scheduler-estimator version: %s", version.Get())
go serveHealthzAndMetrics(net.JoinHostPort(opts.BindAddress, strconv.Itoa(opts.SecurePort)))
profileflag.ListenAndServe(opts.ProfileOpts)
restConfig, err := clientcmd.BuildConfigFromFlags(opts.Master, opts.KubeConfig)
if err != nil {
return fmt.Errorf("error building kubeconfig: %s", err.Error())
}
restConfig.QPS, restConfig.Burst = opts.ClusterAPIQPS, opts.ClusterAPIBurst
kubeClient := kubernetes.NewForConfigOrDie(restConfig)
dynamicClient := dynamic.NewForConfigOrDie(restConfig)
discoveryClient := discovery.NewDiscoveryClientForConfigOrDie(restConfig)
e := server.NewEstimatorServer(kubeClient, dynamicClient, discoveryClient, opts, ctx.Done())
if err = e.Start(ctx); err != nil {
klog.Errorf("estimator server exits unexpectedly: %v", err)
return err
}
// never reach here
return nil
}
func serveHealthzAndMetrics(address string) {
mux := http.NewServeMux()
mux.HandleFunc("/healthz", func(w http.ResponseWriter, _ *http.Request) {
w.WriteHeader(http.StatusOK)
_, _ = w.Write([]byte("ok"))
})
mux.Handle("/metrics", promhttp.HandlerFor(ctrlmetrics.Registry, promhttp.HandlerOpts{
ErrorHandling: promhttp.HTTPErrorOnError,
}))
httpServer := http.Server{
Addr: address,
Handler: mux,
ReadHeaderTimeout: ReadHeaderTimeout,
}
if err := httpServer.ListenAndServe(); err != nil {
klog.Errorf("Failed to serve healthz and metrics: %v", err)
os.Exit(1)
}
}