Log at higher verbosity levels some common SyncPod errors

pkg/kubelet/kuberuntime/kuberuntime_manager.go

@@ -688,7 +688,14 @@ func (m *kubeGenericRuntimeManager) SyncPod(pod *v1.Pod, _ v1.PodStatus, podStat
 		glog.V(4).Infof("Creating container %+v in pod %v", container, format.Pod(pod))
 		if msg, err := m.startContainer(podSandboxID, podSandboxConfig, container, pod, podStatus, pullSecrets, podIP); err != nil {
 			startContainerResult.Fail(err, msg)
-			utilruntime.HandleError(fmt.Errorf("container start failed: %v: %s", err, msg))
+			// known errors that are logged in other places are logged at higher levels here to avoid
+			// repetitive log spam
+			switch {
+			case err == images.ErrImagePullBackOff:
+				glog.V(3).Infof("container start failed: %v: %s", err, msg)
+			default:
+				utilruntime.HandleError(fmt.Errorf("container start failed: %v: %s", err, msg))
+			}
 			continue
 		}
 	}