kube-proxy can read config from the apiserver

All clients that talk to a "master" as a host:port or URL
(scheme://host:port) parameter.  Add tests.

pkg/util/wait/wait.go

@@ -18,9 +18,21 @@ package wait
 
 import (
 	"errors"
+	"math/rand"
 	"time"
 )
 
+// Jitter returns a time.Duration between duration and duration + maxFactor * duration,
+// to allow clients to avoid converging on periodic behavior.  If maxFactor is 0.0, a
+// suggested default value will be chosen.
+func Jitter(duration time.Duration, maxFactor float64) time.Duration {
+	if maxFactor <= 0.0 {
+		maxFactor = 1.0
+	}
+	wait := duration + time.Duration(rand.Float64()*maxFactor*float64(duration))
+	return wait
+}
+
 // ErrWaitTimeout is returned when the condition exited without success
 var ErrWaitTimeout = errors.New("timed out waiting for the condition")