217 lines
7.0 KiB
Go
217 lines
7.0 KiB
Go
/*
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Copyright 2021 The Karmada Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package app
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import (
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"context"
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"fmt"
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"net"
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"net/http"
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"os"
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"strconv"
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"time"
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"github.com/prometheus/client_golang/prometheus/promhttp"
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"github.com/spf13/cobra"
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"k8s.io/apimachinery/pkg/util/uuid"
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"k8s.io/client-go/kubernetes"
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"k8s.io/client-go/rest"
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"k8s.io/client-go/tools/clientcmd"
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"k8s.io/client-go/tools/leaderelection"
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"k8s.io/client-go/tools/leaderelection/resourcelock"
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cliflag "k8s.io/component-base/cli/flag"
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"k8s.io/component-base/term"
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"k8s.io/klog/v2"
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ctrlmetrics "sigs.k8s.io/controller-runtime/pkg/metrics"
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"github.com/karmada-io/karmada/cmd/descheduler/app/options"
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"github.com/karmada-io/karmada/pkg/descheduler"
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karmadaclientset "github.com/karmada-io/karmada/pkg/generated/clientset/versioned"
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"github.com/karmada-io/karmada/pkg/sharedcli"
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"github.com/karmada-io/karmada/pkg/sharedcli/klogflag"
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"github.com/karmada-io/karmada/pkg/sharedcli/profileflag"
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"github.com/karmada-io/karmada/pkg/version"
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"github.com/karmada-io/karmada/pkg/version/sharedcommand"
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)
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const (
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// ReadHeaderTimeout is the amount of time allowed to read
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// request headers.
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// HTTP timeouts are necessary to expire inactive connections
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// and failing to do so might make the application vulnerable
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// to attacks like slowloris which work by sending data very slow,
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// which in case of no timeout will keep the connection active
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// eventually leading to a denial-of-service (DoS) attack.
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// References:
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// - https://en.wikipedia.org/wiki/Slowloris_(computer_security)
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ReadHeaderTimeout = 32 * time.Second
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// WriteTimeout is the amount of time allowed to write the
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// request data.
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// HTTP timeouts are necessary to expire inactive connections
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// and failing to do so might make the application vulnerable
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// to attacks like slowloris which work by sending data very slow,
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// which in case of no timeout will keep the connection active
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// eventually leading to a denial-of-service (DoS) attack.
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WriteTimeout = 5 * time.Minute
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// ReadTimeout is the amount of time allowed to read
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// response data.
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// HTTP timeouts are necessary to expire inactive connections
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// and failing to do so might make the application vulnerable
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// to attacks like slowloris which work by sending data very slow,
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// which in case of no timeout will keep the connection active
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// eventually leading to a denial-of-service (DoS) attack.
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ReadTimeout = 5 * time.Minute
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)
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// NewDeschedulerCommand creates a *cobra.Command object with default parameters
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func NewDeschedulerCommand(stopChan <-chan struct{}) *cobra.Command {
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opts := options.NewOptions()
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cmd := &cobra.Command{
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Use: "karmada-descheduler",
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Long: `The karmada-descheduler evicts replicas from member clusters
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if they are failed to be scheduled for a period of time. It relies on
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karmada-scheduler-estimator to get replica status.`,
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RunE: func(_ *cobra.Command, _ []string) error {
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// validate options
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if errs := opts.Validate(); len(errs) != 0 {
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return errs.ToAggregate()
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}
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if err := run(opts, stopChan); err != nil {
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return err
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}
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return nil
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},
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Args: func(cmd *cobra.Command, args []string) error {
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for _, arg := range args {
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if len(arg) > 0 {
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return fmt.Errorf("%q does not take any arguments, got %q", cmd.CommandPath(), args)
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}
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}
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return nil
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},
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}
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fss := cliflag.NamedFlagSets{}
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genericFlagSet := fss.FlagSet("generic")
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opts.AddFlags(genericFlagSet)
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// Set klog flags
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logsFlagSet := fss.FlagSet("logs")
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klogflag.Add(logsFlagSet)
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cmd.AddCommand(sharedcommand.NewCmdVersion("karmada-descheduler"))
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cmd.Flags().AddFlagSet(genericFlagSet)
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cmd.Flags().AddFlagSet(logsFlagSet)
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cols, _, _ := term.TerminalSize(cmd.OutOrStdout())
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sharedcli.SetUsageAndHelpFunc(cmd, fss, cols)
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return cmd
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}
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func run(opts *options.Options, stopChan <-chan struct{}) error {
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klog.Infof("karmada-descheduler version: %s", version.Get())
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klog.Infof("Please make sure the karmada-scheduler-estimator of all member clusters has been deployed")
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go serveHealthzAndMetrics(net.JoinHostPort(opts.BindAddress, strconv.Itoa(opts.SecurePort)))
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profileflag.ListenAndServe(opts.ProfileOpts)
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restConfig, err := clientcmd.BuildConfigFromFlags(opts.Master, opts.KubeConfig)
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if err != nil {
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return fmt.Errorf("error building kubeconfig: %s", err.Error())
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}
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restConfig.QPS, restConfig.Burst = opts.KubeAPIQPS, opts.KubeAPIBurst
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karmadaClient := karmadaclientset.NewForConfigOrDie(restConfig)
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kubeClient := kubernetes.NewForConfigOrDie(restConfig)
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ctx, cancel := context.WithCancel(context.Background())
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go func() {
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<-stopChan
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cancel()
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}()
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desched := descheduler.NewDescheduler(karmadaClient, kubeClient, opts)
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if !opts.LeaderElection.LeaderElect {
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desched.Run(ctx)
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return fmt.Errorf("descheduler exited")
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}
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leaderElectionClient, err := kubernetes.NewForConfig(rest.AddUserAgent(restConfig, "leader-election"))
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if err != nil {
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return err
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}
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hostname, err := os.Hostname()
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if err != nil {
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return fmt.Errorf("unable to get hostname: %v", err)
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}
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// add a uniquifier so that two processes on the same host don't accidentally both become active
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id := hostname + "_" + string(uuid.NewUUID())
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rl, err := resourcelock.New(opts.LeaderElection.ResourceLock,
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opts.LeaderElection.ResourceNamespace,
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opts.LeaderElection.ResourceName,
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leaderElectionClient.CoreV1(),
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leaderElectionClient.CoordinationV1(),
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resourcelock.ResourceLockConfig{
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Identity: id,
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})
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if err != nil {
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return fmt.Errorf("couldn't create resource lock: %v", err)
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}
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leaderelection.RunOrDie(ctx, leaderelection.LeaderElectionConfig{
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Lock: rl,
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LeaseDuration: opts.LeaderElection.LeaseDuration.Duration,
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RenewDeadline: opts.LeaderElection.RenewDeadline.Duration,
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RetryPeriod: opts.LeaderElection.RetryPeriod.Duration,
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Callbacks: leaderelection.LeaderCallbacks{
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OnStartedLeading: desched.Run,
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OnStoppedLeading: func() {
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klog.Fatalf("leaderelection lost")
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},
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},
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})
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return nil
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}
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func serveHealthzAndMetrics(address string) {
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mux := http.NewServeMux()
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mux.HandleFunc("/healthz", func(w http.ResponseWriter, _ *http.Request) {
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w.WriteHeader(http.StatusOK)
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_, _ = w.Write([]byte("ok"))
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})
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mux.Handle("/metrics", promhttp.HandlerFor(ctrlmetrics.Registry, promhttp.HandlerOpts{
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ErrorHandling: promhttp.HTTPErrorOnError,
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}))
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httpServer := http.Server{
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Addr: address,
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Handler: mux,
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ReadHeaderTimeout: ReadHeaderTimeout,
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WriteTimeout: WriteTimeout,
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ReadTimeout: ReadTimeout,
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}
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if err := httpServer.ListenAndServe(); err != nil {
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klog.Errorf("Failed to serve healthz and metrics: %v", err)
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os.Exit(1)
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}
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}
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