| 2014-09-12 10:56:03 |
Artyom |
description |
After upgrade Ubuntu server from 12.04 LTS to 14.04 LTS (with do-release-upgrade) I found a strange behavior in /var/log/messages from isc-dhcp-server. It had doubled DHCPREQUESTS/OFFERS/ACKs... It was like:
~~
dhcpd: DHCPDISCOVER from 00:0b:82:27:be:d1 via eth0
dhcpd: DHCPDISCOVER from 00:0b:82:27:be:d1 via eth0
DHCPREQUEST for 192.168.1.102 (10.112.1.252) from 00:0b:82:27:be:d1 via eth0
DHCPREQUEST for 192.168.1.102 (10.112.1.252) from 00:0b:82:27:be:d1 via eth0
DHCPACK on 192.168.1.102 to 00:0b:82:27:be:d1 via eth0
DHCPACK on 192.168.1.102 to 00:0b:82:27:be:d1 via eth0
~~
Futher investigation show that there was actually two dhcpd processes:
~~
dhcpd -q -cf /etc/dhcp/dhcpd.conf -pf /var/run/dhcp-server/dhcpd.pid
/usr/sbin/dhcpd -q -cf /etc/dhcp/dhcpd.conf -pf /var/run/dhcpd.pid
~~
The first one was executed from "/etc/init/isc-dhcp-server.conf" and second from "/etc/init.d/isc-dhcp-server".
Looking inside "init/isc-dhcp-server.conf" I found:
~~
respawn
script
. /etc/default/isc-dhcp-server
......
exec dhcpd -user dhcpd -group dhcpd -f -q -4 -pf /run/dhcp-server/dhcpd.pid -cf $CONFIG_FILE $INTERFACES
~~
As you can see path to PID file is hardcoded.
But in "init.d/isc-dhcp-server" startup script:
~~
# try to read pid file name from config file, with fallback to /var/run/dhcpd.pid
if [ -z "$DHCPD_PID" ]; then
DHCPD_PID=$(sed -n -e 's/^[ \t]*pid-file-name[ \t]*"(.*)"[ \t]*;.*$/\1/p' < "$DHCPD_CONF" 2>/dev/null | head -n 1)
fi
DHCPD_PID="${DHCPD_PID:-/var/run/dhcpd.pid}"
......
case "$1" in
start)
test_config
log_daemon_msg "Starting $DESC" "$NAME"
start-stop-daemon --start --quiet --pidfile "$DHCPD_PID" \
--exec /usr/sbin/dhcpd -- \
-q $OPTIONS -cf "$DHCPD_CONF" -pf "$DHCPD_PID" $INTERFACES
~~ |
After upgrade Ubuntu server from 12.04 LTS to 14.04 LTS (with do-release-upgrade) I found a strange behavior in /var/log/messages from isc-dhcp-server. It had doubled DHCPREQUESTS/OFFERS/ACKs... It was like:
~~
dhcpd: DHCPDISCOVER from 00:0b:82:27:be:d1 via eth0
dhcpd: DHCPDISCOVER from 00:0b:82:27:be:d1 via eth0
DHCPREQUEST for 192.168.1.102 (10.112.1.252) from 00:0b:82:27:be:d1 via eth0
DHCPREQUEST for 192.168.1.102 (10.112.1.252) from 00:0b:82:27:be:d1 via eth0
DHCPACK on 192.168.1.102 to 00:0b:82:27:be:d1 via eth0
DHCPACK on 192.168.1.102 to 00:0b:82:27:be:d1 via eth0
~~
Futher investigation show that there was actually two dhcpd processes:
~~
dhcpd -q -cf /etc/dhcp/dhcpd.conf -pf /var/run/dhcp-server/dhcpd.pid
/usr/sbin/dhcpd -q -cf /etc/dhcp/dhcpd.conf -pf /var/run/dhcpd.pid
~~
The first one was executed from "/etc/init/isc-dhcp-server.conf" and second from "/etc/init.d/isc-dhcp-server".
Looking inside "init/isc-dhcp-server.conf" I found:
~~
respawn
script
. /etc/default/isc-dhcp-server
......
exec dhcpd -user dhcpd -group dhcpd -f -q -4 -pf /run/dhcp-server/dhcpd.pid -cf $CONFIG_FILE $INTERFACES
~~
As you can see path to PID file is hardcoded.
But in "init.d/isc-dhcp-server" startup script:
~~
# try to read pid file name from config file, with fallback to /var/run/dhcpd.pid
if [ -z "$DHCPD_PID" ]; then
DHCPD_PID=$(sed -n -e 's/^[ \t]*pid-file-name[ \t]*"(.*)"[ \t]*;.*$/\1/p' < "$DHCPD_CONF" 2>/dev/null | head -n 1)
fi
DHCPD_PID="${DHCPD_PID:-/var/run/dhcpd.pid}"
......
case "$1" in
start)
test_config
log_daemon_msg "Starting $DESC" "$NAME"
start-stop-daemon --start --quiet --pidfile "$DHCPD_PID" \
--exec /usr/sbin/dhcpd -- \
-q $OPTIONS -cf "$DHCPD_CONF" -pf "$DHCPD_PID" $INTERFACES
~~
So obivous is to either change init script to NOT use hardcoded path to PID file and use $DHCP_PID (from /etc/default/isc-dhcp-server, which is sourced inside this script), or at least change it to "default" one: /var/run/dhcpd.pid
OR
change init.d script to fallback to "/run/dhcp-server/dhcpd.pid" instead of "/var/run/dhcpd.pid"
P.S. /var/run is a link to /run |
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