diff --git a/pkg/master/master.go b/pkg/master/master.go
index fe080c2103c..88c1b5a25c0 100644
--- a/pkg/master/master.go
+++ b/pkg/master/master.go
@@ -452,7 +452,7 @@ func (c completedConfig) New(delegationTarget genericapiserver.DelegationTarget)
 func (m *Master) InstallLegacyAPI(c *completedConfig, restOptionsGetter generic.RESTOptionsGetter, legacyRESTStorageProvider corerest.LegacyRESTStorageProvider) error {
 	legacyRESTStorage, apiGroupInfo, err := legacyRESTStorageProvider.NewLegacyRESTStorage(restOptionsGetter)
 	if err != nil {
-		return fmt.Errorf("Error building core storage: %v", err)
+		return fmt.Errorf("error building core storage: %v", err)
 	}
 
 	controllerName := "bootstrap-controller"
@@ -462,7 +462,7 @@ func (m *Master) InstallLegacyAPI(c *completedConfig, restOptionsGetter generic.
 	m.GenericAPIServer.AddPreShutdownHookOrDie(controllerName, bootstrapController.PreShutdownHook)
 
 	if err := m.GenericAPIServer.InstallLegacyAPIGroup(genericapiserver.DefaultLegacyAPIPrefix, &apiGroupInfo); err != nil {
-		return fmt.Errorf("Error in registering group versions: %v", err)
+		return fmt.Errorf("error in registering group versions: %v", err)
 	}
 	return nil
 }
@@ -518,7 +518,7 @@ func (m *Master) InstallAPIs(apiResourceConfigSource serverstorage.APIResourceCo
 	}
 
 	if err := m.GenericAPIServer.InstallAPIGroups(apiGroupsInfo...); err != nil {
-		return fmt.Errorf("Error in registering group versions: %v", err)
+		return fmt.Errorf("error in registering group versions: %v", err)
 	}
 	return nil
 }
diff --git a/pkg/master/services.go b/pkg/master/services.go
index 420d2fcbf19..5b4d3897853 100644
--- a/pkg/master/services.go
+++ b/pkg/master/services.go
@@ -40,7 +40,7 @@ func ServiceIPRange(passedServiceClusterIPRange net.IPNet) (net.IPNet, net.IP, e
 
 	size := integer.Int64Min(utilnet.RangeSize(&serviceClusterIPRange), 1<<16)
 	if size < 8 {
-		return net.IPNet{}, net.IP{}, fmt.Errorf("The service cluster IP range must be at least %d IP addresses", 8)
+		return net.IPNet{}, net.IP{}, fmt.Errorf("the service cluster IP range must be at least %d IP addresses", 8)
 	}
 
 	// Select the first valid IP from ServiceClusterIPRange to use as the GenericAPIServer service IP.
diff --git a/pkg/master/tunneler/ssh.go b/pkg/master/tunneler/ssh.go
index f30a967e34b..684ba812f7b 100644
--- a/pkg/master/tunneler/ssh.go
+++ b/pkg/master/tunneler/ssh.go
@@ -55,7 +55,7 @@ func TunnelSyncHealthChecker(tunneler Tunneler) func(req *http.Request) error {
 		}
 		lag := tunneler.SecondsSinceSync()
 		if lag > 600 {
-			return fmt.Errorf("Tunnel sync is taking too long: %d", lag)
+			return fmt.Errorf("tunnel sync is taking too long: %d", lag)
 		}
 		sshKeyLag := tunneler.SecondsSinceSSHKeySync()
 		// Since we are syncing ssh-keys every 5 minutes, the allowed