From 9aad66b3a08b78266e4037092cde4769f5815916 Mon Sep 17 00:00:00 2001
From: Oleksandr Ivantsiv <oleksandri@mellanox.com>
Date: Wed, 1 Feb 2017 18:54:16 +0200
Subject: [PATCH 1/3] Add DHCP client hook to update hostname.

---
 build_debian.sh        |  1 +
 files/dhcp/sethostname | 21 +++++++++++++++++++++
 2 files changed, 22 insertions(+)
 create mode 100644 files/dhcp/sethostname

diff --git a/build_debian.sh b/build_debian.sh
index d79a05275b17..e113e6925107 100755
--- a/build_debian.sh
+++ b/build_debian.sh
@@ -240,6 +240,7 @@ iface eth0 inet dhcp
 EOF
 
 sudo cp files/dhcp/rfc3442-classless-routes $FILESYSTEM_ROOT/etc/dhcp/dhclient-exit-hooks.d
+sudo cp files/dhcp/sethostname $FILESYSTEM_ROOT/etc/dhcp/dhclient-exit-hooks.d/
 
 if [ -f sonic_debian_extension.sh ]; then
     ./sonic_debian_extension.sh $FILESYSTEM_ROOT
diff --git a/files/dhcp/sethostname b/files/dhcp/sethostname
new file mode 100644
index 000000000000..7b59862a13bd
--- /dev/null
+++ b/files/dhcp/sethostname
@@ -0,0 +1,21 @@
+#!/bin/bash
+# This script is to update hostname of the system.
+
+if [ "$reason" != BOUND ] && [ "$reason" != RENEW ] \
+     && [ "$reason" != REBIND ] && [ "$reason" != REBOOT ]
+then
+    exit 0
+fi
+
+if [ "$interface" != "eth0" ] && [ "$interface" != "eth1" ]
+then
+    exit 0
+fi
+
+current_host_name=`hostname -s`
+
+if [ "$current_host_name" != "$new_host_name" ]
+then
+    echo $new_host_name > /etc/hostname
+    hostname -F /etc/hostname
+fi

From 3b4c1914346c7fd0f66f3a41ba02014befed5ba7 Mon Sep 17 00:00:00 2001
From: Oleksandr Ivantsiv <oleksandri@mellanox.com>
Date: Thu, 2 Feb 2017 11:14:44 +0200
Subject: [PATCH 2/3] Remove interface checking

---
 files/dhcp/sethostname | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/files/dhcp/sethostname b/files/dhcp/sethostname
index 7b59862a13bd..07bc3566da6b 100644
--- a/files/dhcp/sethostname
+++ b/files/dhcp/sethostname
@@ -7,11 +7,6 @@ then
     exit 0
 fi
 
-if [ "$interface" != "eth0" ] && [ "$interface" != "eth1" ]
-then
-    exit 0
-fi
-
 current_host_name=`hostname -s`
 
 if [ "$current_host_name" != "$new_host_name" ]

From e8d7ce3adaa8051cb1feabd10e9ee79a233fd57d Mon Sep 17 00:00:00 2001
From: Oleksandr Ivantsiv <oleksandri@mellanox.com>
Date: Thu, 2 Feb 2017 17:44:49 +0200
Subject: [PATCH 3/3] Update hostname in /etc/hosts file

---
 files/dhcp/sethostname | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/files/dhcp/sethostname b/files/dhcp/sethostname
index 07bc3566da6b..81bd458935fc 100644
--- a/files/dhcp/sethostname
+++ b/files/dhcp/sethostname
@@ -12,5 +12,9 @@ current_host_name=`hostname -s`
 if [ "$current_host_name" != "$new_host_name" ]
 then
     echo $new_host_name > /etc/hostname
+    line_to_replace=`grep 127.0.0.1.*$current_host_name /etc/hosts`
+    new_line=`echo $line_to_replace | sed "s/$current_host_name/$new_host_name/"`
+    sed -i "s/$line_to_replace/$new_line/" /etc/hosts
+
     hostname -F /etc/hostname
 fi