cluster: better upgrade logging

pkg/cluster/upgrade.go

@@ -9,16 +9,17 @@ import (
 )
 
 func (c *Cluster) upgradeOneMember(m *etcdutil.Member) error {
-	logrus.Infof("upgrading an member: %v", m.Name)
 	pod, err := c.kclient.Pods(c.namespace).Get(m.Name)
 	if err != nil {
 		return fmt.Errorf("fail to get pod (%s): %v", m.Name, err)
 	}
+	logrus.Infof("upgrading the etcd member %v from %s to %s", m.Name, k8sutil.GetEtcdVersion(pod), c.spec.Version)
 	pod.Spec.Containers[0].Image = k8sutil.MakeEtcdImage(c.spec.Version)
 	k8sutil.SetEtcdVersion(pod, c.spec.Version)
 	_, err = c.kclient.Pods(c.namespace).Update(pod)
 	if err != nil {
-		return fmt.Errorf("fail to update pod (%s): %v", m.Name, err)
+		return fmt.Errorf("fail to update the etcd member (%s): %v", m.Name, err)
 	}
+	logrus.Infof("finished upgrading the etcd member %v", m.Name)
 	return nil
 }