From 06e12f7020caa2b8a2e1c43ca28f38e7915b4055 Mon Sep 17 00:00:00 2001
From: kevinlin <linjiang1205@gmail.com>
Date: Sun, 9 Oct 2022 18:17:31 +0800
Subject: [PATCH] Update: tips about warnning log

---
 docs/reverse-proxy.md | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/docs/reverse-proxy.md b/docs/reverse-proxy.md
index 4ab7ac00..2bfbcfb2 100644
--- a/docs/reverse-proxy.md
+++ b/docs/reverse-proxy.md
@@ -61,7 +61,10 @@ server {
 ```
 
 ## istio/envoy
-If you using [Istio](https://istio.io/) ingressgateway or [Envoy](https://www.envoyproxy.io/) as reverse proxy, there are some tips for you. 
+If you using [Istio](https://istio.io/) ingressgateway or [Envoy](https://www.envoyproxy.io/) as reverse proxy, there are some tips for you.  If not set, you may see some debug log in proxy as below:
+```log
+Sending local reply with details upgrade_failed
+```
 
 ### Envoy
 You need add a new upgrade_type named `tailscale-control-protocol`. [see detail](https://www.envoyproxy.io/docs/envoy/latest/api-v3/extensions/filters/network/http_connection_manager/v3/http_connection_manager.proto#extensions-filters-network-http-connection-manager-v3-httpconnectionmanager-upgradeconfig)