From 7ff5b05004570f9f5808dfde1a57bb8d75e07c12 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 a2713c9e61a..7ab77d986c3 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 bf0cd7f75d2..e574ab10dc0 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",