From d9b21c79d4f5c7d0b95e090376e31e2c00c70599 Mon Sep 17 00:00:00 2001
From: Xiang Li <xiang.li@coreos.com>
Date: Thu, 11 Dec 2014 15:42:54 -0800
Subject: [PATCH] etcdmain: better logging for discovery error

---
 discovery/discovery.go | 3 +++
 etcdmain/etcd.go       | 8 +++++++-
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/discovery/discovery.go b/discovery/discovery.go
index 9ea7ea65f..3dbb7b470 100644
--- a/discovery/discovery.go
+++ b/discovery/discovery.go
@@ -181,6 +181,9 @@ func (d *discovery) createSelf(contents string) error {
 	resp, err := d.c.Create(ctx, d.selfKey(), contents, -1)
 	cancel()
 	if err != nil {
+		if err == client.ErrKeyExists {
+			return ErrDuplicateID
+		}
 		return err
 	}
 
diff --git a/etcdmain/etcd.go b/etcdmain/etcd.go
index 6fd2d64db..9be2cd2bb 100644
--- a/etcdmain/etcd.go
+++ b/etcdmain/etcd.go
@@ -189,7 +189,13 @@ func Main() {
 		err = startProxy()
 	}
 	if err != nil {
-		log.Fatalf("etcd: %v", err)
+		switch err {
+		case discovery.ErrDuplicateID:
+			log.Fatalf("etcd: member %s has previously registered with discovery service (%s), but the data-dir (%s) on disk cannot be found.",
+				*name, *durl, *dir)
+		default:
+			log.Fatalf("etcd: %v", err)
+		}
 	}
 	<-stopped
 }