From 5708f6f39e5c2d3fbf3d1b27fe45796cacd7c326 Mon Sep 17 00:00:00 2001
From: Anthony Romano <anthony.romano@coreos.com>
Date: Mon, 12 Jun 2017 13:36:32 -0700
Subject: [PATCH] etcdserver: better warning when initial-cluster doesn't match
 advertise urls

The old error was not clear about what URLs needed to be added, sometimes
truncating the list. To make it clearer, print out the missing entries
for --initial-cluster and print the full list of initial advertise peers.

Fixes #8079 and #7927
---
 etcdserver/config.go      | 38 ++++++++++++++++++++++++++++++++++----
 etcdserver/config_test.go |  8 ++++++++
 2 files changed, 42 insertions(+), 4 deletions(-)

diff --git a/etcdserver/config.go b/etcdserver/config.go
index a2713c9e61a9..7ab77d986c3b 100644
--- a/etcdserver/config.go
+++ b/etcdserver/config.go
@@ -117,11 +117,41 @@ func (c *ServerConfig) advertiseMatchesCluster() error {
 	sort.Strings(apurls)
 	ctx, cancel := context.WithTimeout(context.TODO(), 30*time.Second)
 	defer cancel()
-	if !netutil.URLStringsEqual(ctx, apurls, urls.StringSlice()) {
-		umap := map[string]types.URLs{c.Name: c.PeerURLs}
-		return fmt.Errorf("--initial-cluster must include %s given --initial-advertise-peer-urls=%s", types.URLsMap(umap).String(), strings.Join(apurls, ","))
+	if netutil.URLStringsEqual(ctx, apurls, urls.StringSlice()) {
+		return nil
 	}
-	return nil
+
+	initMap, apMap := make(map[string]struct{}), make(map[string]struct{})
+	for _, url := range c.PeerURLs {
+		apMap[url.String()] = struct{}{}
+	}
+	for _, url := range c.InitialPeerURLsMap[c.Name] {
+		initMap[url.String()] = struct{}{}
+	}
+
+	missing := []string{}
+	for url := range initMap {
+		if _, ok := apMap[url]; !ok {
+			missing = append(missing, url)
+		}
+	}
+	if len(missing) > 0 {
+		for i := range missing {
+			missing[i] = c.Name + "=" + missing[i]
+		}
+		mstr := strings.Join(missing, ",")
+		apStr := strings.Join(apurls, ",")
+		return fmt.Errorf("--initial-cluster has %s but missing from --initial-advertise-peer-urls=%s ", mstr, apStr)
+	}
+
+	for url := range apMap {
+		if _, ok := initMap[url]; !ok {
+			missing = append(missing, url)
+		}
+	}
+	mstr := strings.Join(missing, ",")
+	umap := types.URLsMap(map[string]types.URLs{c.Name: c.PeerURLs})
+	return fmt.Errorf("--initial-advertise-peer-urls has %s but missing from --initial-cluster=%s", mstr, umap.String())
 }
 
 func (c *ServerConfig) MemberDir() string { return filepath.Join(c.DataDir, "member") }
diff --git a/etcdserver/config_test.go b/etcdserver/config_test.go
index bf0cd7f75d21..e574ab10dc04 100644
--- a/etcdserver/config_test.go
+++ b/etcdserver/config_test.go
@@ -107,6 +107,14 @@ func TestConfigVerifyLocalMember(t *testing.T) {
 
 			true,
 		},
+		{
+			// Advertised peer URLs must match those in cluster-state
+			"node1=http://localhost:12345",
+			[]string{"http://localhost:2380", "http://localhost:12345"},
+			true,
+
+			true,
+		},
 		{
 			// Advertised peer URLs must match those in cluster-state
 			"node1=http://localhost:2380",