NTP Client Start/Stop (Korn shell)

Hochschule Augsburg

NTP Service - Usage

Client Start/Stop Script

#!/bin/sh
#
# /sbin/xntp
#

killproc() {  # kill named processes
  pid=`/usr/bin/ps -e |
       /usr/bin/grep $1 |
       /usr/bin/sed -e 's/^  *//' -e 's/ .*//'`
  [ "$pid" != "" ] && kill $pid
}

startntp() {  # start xntpd daemon
  if [ -f /etc/ntp.conf -a -x /usr/local/bin/xntpd ]
  then
#   /usr/local/bin/tickadj -A
    /usr/local/bin/ntpdate kipling.rz.fh-augsburg.de
    /usr/local/bin/ntpdate compact.rz.fh-augsburg.de
    /usr/local/bin/ntpdate kim.rz.fh-augsburg.de
    ulimit -s 128
    /usr/local/bin/xntpd -c /etc/ntp.conf
  fi
}

case "$1" in
'start')
  ps -e | grep xntpd > /dev/null 2>&1
  if [ $? -eq 0 ]
  then
    echo "ntp daemon already running. ntp start aborted"
    exit 0
  fi
  startntp
  ;;
'stop')
  killproc xntpd
  ;;
'restart')
  ps -e | grep xntpd > /dev/null 2>&1
  if [ $? -eq 0 ]
  then
    killproc xntpd
  fi
  startntp
  ;;
*)
  echo "Usage: /sbin/xntp { start | stop | restart }"
  ;;
esac

This is a template start/stop script especially suitable for AIX. You may have to adapt it to your environment. Check the path to the shell, to the xntp binaries, and to the script itself.

The call to tickadj -A resets the tickadj kernel variable to its default. This or another value (e.g. tickadj -a 120) may be required if the system clock is peered in the configuration. If the daemon doesn't stabilize, you should read the topic 'Dealing with Frequency Tolerance Violations (tickadj and Friends)' in Notes on Configuring NTP and Setting up a NTP Subnet in the documentation. You will also need the tickadj manpage. Especially for AIX machines the NTP FAQ should be scanned for special information. Good luck!

The threefold call of ntpdate will correct your system clock to a very good value before starting the daemon. The offset to UTC will be about +/- 10 ms without much delay. If one of the servers is down there are still two. The here mentioned servers are in our department network. They are reachable in our campus network only, so you have to poll different ones if you are not in here.

The line ulimit -s 128 is strongly recommended for AIX, though not for other Unix variants. The daemon will fill up much of the system memory if this command is missing.

Restarting would be needed to force a configuration file reread or to trim a log file. Both are not needed in this client configuration.

1999-07-15