From e15bc28967e70841ceff43442d1066cd87c775b0 Mon Sep 17 00:00:00 2001
From: Wayne Song <wsong@docker.com>
Date: Mon, 28 Nov 2016 09:23:51 -0800
Subject: [PATCH] Don't forward _ping requests to the primary

Signed-off-by: Wayne Song <wsong@docker.com>
---
 api/replica.go | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/api/replica.go b/api/replica.go
index 36ad027de0..2bb8612574 100644
--- a/api/replica.go
+++ b/api/replica.go
@@ -7,7 +7,7 @@ import (
 	"strings"
 )
 
-var localRoutes = []string{"/_ping", "/info", "/debug"}
+var localRoutes = []string{"/info", "/debug"}
 
 // Replica is an API replica that reserves proxy to the primary.
 type Replica struct {
@@ -46,6 +46,13 @@ func (p *Replica) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	// We also handle /_ping locally, but we do so after the primary
+	// check above.
+	if strings.HasSuffix(r.URL.Path, "/_ping") {
+		w.Write([]byte("OK"))
+		return
+	}
+
 	if err := hijack(p.tlsConfig, p.primary, w, r); err != nil {
 		httpError(w, fmt.Sprintf("Unable to reach primary cluster manager (%s): %v", err, p.primary), http.StatusInternalServerError)
 	}