From e1622cd22c282eb752fb783ba791b994b0ca3714 Mon Sep 17 00:00:00 2001
From: Brian Akins <brian.akins@coreos.com>
Date: Tue, 7 Apr 2015 15:40:29 -0400
Subject: [PATCH 1/2] proxy: shuffle endpoints

Shuffle endpoitns to avoid being "stuck" to a single cluster member.
---
 Documentation/proxy.md | 2 ++
 proxy/director.go      | 8 ++++++++
 2 files changed, 10 insertions(+)

diff --git a/Documentation/proxy.md b/Documentation/proxy.md
index ab9c8a1b5..cbf63e4e2 100644
--- a/Documentation/proxy.md
+++ b/Documentation/proxy.md
@@ -4,6 +4,8 @@ etcd can now run as a transparent proxy. Running etcd as a proxy allows for easi
 
 etcd currently supports two proxy modes: `readwrite` and `readonly`. The default mode is `readwrite`, which forwards both read and write requests to the etcd cluster. A `readonly` etcd proxy only forwards read requests to the etcd cluster, and returns `HTTP 501` to all write requests. 
 
+etcd will shuffle the list of cluster members periodically to avoid sending all connections to a single member.
+
 ### Using an etcd proxy
 To start etcd in proxy mode, you need to provide three flags: `proxy`, `listen-client-urls`, and `initial-cluster` (or `discovery`). 
 
diff --git a/proxy/director.go b/proxy/director.go
index 862690d4d..e795b27fb 100644
--- a/proxy/director.go
+++ b/proxy/director.go
@@ -16,6 +16,7 @@ package proxy
 
 import (
 	"log"
+	"math/rand"
 	"net/url"
 	"sync"
 	"time"
@@ -65,6 +66,13 @@ func (d *director) refresh() {
 		}
 		endpoints = append(endpoints, newEndpoint(*uu))
 	}
+
+	// shuffle array to avoid connections being "stuck" to a single endpoint
+	for i := range endpoints {
+		j := rand.Intn(i + 1)
+		endpoints[i], endpoints[j] = endpoints[j], endpoints[i]
+	}
+
 	d.ep = endpoints
 }
 

From 1fa511b9952d49befba9cb69383f36c82700f37c Mon Sep 17 00:00:00 2001
From: Brian Akins <brian.akins@coreos.com>
Date: Tue, 7 Apr 2015 17:05:17 -0400
Subject: [PATCH 2/2] Clarify that it is the proxy doing the shuffle.

---
 Documentation/proxy.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Documentation/proxy.md b/Documentation/proxy.md
index cbf63e4e2..7e2e8b4da 100644
--- a/Documentation/proxy.md
+++ b/Documentation/proxy.md
@@ -4,7 +4,7 @@ etcd can now run as a transparent proxy. Running etcd as a proxy allows for easi
 
 etcd currently supports two proxy modes: `readwrite` and `readonly`. The default mode is `readwrite`, which forwards both read and write requests to the etcd cluster. A `readonly` etcd proxy only forwards read requests to the etcd cluster, and returns `HTTP 501` to all write requests. 
 
-etcd will shuffle the list of cluster members periodically to avoid sending all connections to a single member.
+The proxy will shuffle the list of cluster members periodically to avoid sending all connections to a single member.
 
 ### Using an etcd proxy
 To start etcd in proxy mode, you need to provide three flags: `proxy`, `listen-client-urls`, and `initial-cluster` (or `discovery`).