@@ -56,6 +56,12 @@ func discoveryOpts(clusterOpts map[string]string) (time.Duration, time.Duration,

 		if err != nil {

 			return time.Duration(0), time.Duration(0), err

 		}

+

+		if h <= 0 {

+			return time.Duration(0), time.Duration(0),

+				fmt.Errorf("discovery.heartbeat must be positive")

+		}

+

 		heartbeat = time.Duration(h) * time.Second

 		ttl = defaultDiscoveryTTLFactor * heartbeat

 	}

@@ -65,6 +71,12 @@ func discoveryOpts(clusterOpts map[string]string) (time.Duration, time.Duration,

 		if err != nil {

 			return time.Duration(0), time.Duration(0), err

 		}

+

+		if t <= 0 {

+			return time.Duration(0), time.Duration(0),

+				fmt.Errorf("discovery.ttl must be positive")

+		}

+

 		ttl = time.Duration(t) * time.Second

 		if _, ok := clusterOpts["discovery.heartbeat"]; !ok {

@@ -18,6 +18,18 @@ func TestDiscoveryOpts(t *testing.T) {

 		t.Fatalf("discovery.ttl == discovery.heartbeat must fail")

 	}

+	clusterOpts = map[string]string{"discovery.heartbeat": "-10", "discovery.ttl": "10"}

+	heartbeat, ttl, err = discoveryOpts(clusterOpts)

+	if err == nil {

+		t.Fatalf("negative discovery.heartbeat must fail")

+	}

+

+	clusterOpts = map[string]string{"discovery.heartbeat": "10", "discovery.ttl": "-10"}

+	heartbeat, ttl, err = discoveryOpts(clusterOpts)

+	if err == nil {

+		t.Fatalf("negative discovery.ttl must fail")

+	}

+

 	clusterOpts = map[string]string{"discovery.heartbeat": "invalid"}

 	heartbeat, ttl, err = discoveryOpts(clusterOpts)

 	if err == nil {