Two bug fixes: (1) at least log something out if we fail to register our health check, (2) actually register a prometheus metric. I delete the deprecated metric in this block because there isn't any point to it, since no one can be broken by changing a metric that doesn't get collected

Author: Han Kang

pkg/master/master.go

@@ -469,15 +469,10 @@ func (m *Master) InstallLegacyAPI(c *completedConfig, restOptionsGetter generic.
 
 func (m *Master) installTunneler(nodeTunneler tunneler.Tunneler, nodeClient corev1client.NodeInterface) {
 	nodeTunneler.Run(nodeAddressProvider{nodeClient}.externalAddresses)
-	m.GenericAPIServer.AddHealthChecks(healthz.NamedCheck("SSH Tunnel Check", tunneler.TunnelSyncHealthChecker(nodeTunneler)))
-	prometheus.NewGaugeFunc(prometheus.GaugeOpts{
-		Name: "apiserver_proxy_tunnel_sync_duration_seconds",
-		Help: "The time since the last successful synchronization of the SSH tunnels for proxy requests.",
-	}, func() float64 { return float64(nodeTunneler.SecondsSinceSync()) })
-	prometheus.NewGaugeFunc(prometheus.GaugeOpts{
-		Name: "apiserver_proxy_tunnel_sync_latency_secs",
-		Help: "(Deprecated) The time since the last successful synchronization of the SSH tunnels for proxy requests.",
-	}, func() float64 { return float64(nodeTunneler.SecondsSinceSync()) })
+	err := m.GenericAPIServer.AddHealthChecks(healthz.NamedCheck("SSH Tunnel Check", tunneler.TunnelSyncHealthChecker(nodeTunneler)))
+	if err != nil {
+		klog.Errorf("Failed adding ssh tunnel health check %v\n", err)
+	}
 }
 
 // RESTStorageProvider is a factory type for REST storage.