FakeClientset: bump watch channel size

Huge clusters with thousands of pods can quickly exceed the default
watch channel size of the fake clientset. Causing the channel
to panic with "channel full".

cmd/descheduler/app/server.go

@@ -31,6 +31,7 @@ import (
 
 	"github.com/spf13/cobra"
 
+	"k8s.io/apimachinery/pkg/watch"
 	apiserver "k8s.io/apiserver/pkg/server"
 	"k8s.io/apiserver/pkg/server/mux"
 	restclient "k8s.io/client-go/rest"
@@ -111,6 +112,9 @@ func NewDeschedulerCommand(out io.Writer) *cobra.Command {
 }
 
 func Run(ctx context.Context, rs *options.DeschedulerServer) error {
+	// increase the fake watch channel so the dry-run mode can be run
+	// over a cluster with thousands of pods
+	watch.DefaultChanSize = 100000
 	return descheduler.Run(ctx, rs)
 }