From f11112371d50a604829e8a6c5c333e87ea94185f Mon Sep 17 00:00:00 2001
From: MD NADEEM <mail2nadeem92@gmail.com>
Date: Tue, 15 Mar 2016 15:00:30 +0530
Subject: [PATCH] Fix race condition in haproxy
The time period between getting pid
of haproxy service and checking existance of
pid file is very short, if with in this period
haproxy service get reload then the race condition
occured and container get exit as extend_start.sh
script exit.
To minimize the risk of race condition, this patch
let the extend_start.sh script to try upto 3 times
before exit.
Closes-Bug: #1479888
Change-Id: I2f9b7ec832dec8d94a2cdd27ca8a212d0c65a60d
---
docker/haproxy/extend_start.sh | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)
diff --git a/docker/haproxy/extend_start.sh b/docker/haproxy/extend_start.sh
index 16a65c0af..c33780d20 100644
--- a/docker/haproxy/extend_start.sh
+++ b/docker/haproxy/extend_start.sh
@@ -7,11 +7,16 @@ sysctl net.unix.max_dgram_qlen=128
echo "Running command: '${CMD}'"
$CMD
-# TODO(SamYaple): This has the potential for a race condition triggered by a
-# config reload that could cause the container to exit
-while [[ -e "/proc/$(cat /run/haproxy.pid)" ]]; do
+retry=0
+# The loop breaks only when haproxy.pid get missing even after 3 re-try.
+while [[ $retry -lt 3 ]]; do
+ if [[ ! -e /run/haproxy.pid || ! -d /proc/$(cat /run/haproxy.pid) ]]; then
+ retry=$((retry+1))
+ sleep 2
+ continue
+ fi
+ retry=0
sleep 5
done
-# Based on the above loop this point should never be reached
exit 1
--
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