Automatic Restart

Occassionally the computer will be re-booted or one of the servers will disappear. We run a crontab script that checks the status of the programs periodically and re-starts them as necessary.

Location data
maintainer	Robot Vision Lab
machine	rvl2.ecn.purdue.edu
mechanism	crontab
check script	/home/rvl2/d/asldata/bin/jsrvr.chk
ASL Server start script	/home/rvl2/d/asldata/bin/jsrvr.start
check interval	5 minutes
log files
startup	/home/rvl2/d/asldata/JDBC/tmp/JDBCServer.log
ASL Server	/tmp/JDBCServer.out
MySQL Server	/tmp/mysqld.log

To edit the crontab file, use

  bash # (Unless you use this by default)
  export EDITOR=emacs
  crontab -e

The crontab file contains a single line:

0 11 * * * * /home/rvl2/d/asldata/bin/jsrvr.chk

To forward any errors the crontab file makes to your personal web account, use

  cd ~/
  echo 'username@location.com' > .forward

All of this is documented in the jsrvr.chk file, as well:

 /bin/jsrvr.chk

#!/bin/sh
#
# Shell Script for Starting the RVL-SLLL ASL Database Automatically
#
# Josiah Yoder
# This shell script is called from a script automatically, using crontab.
# To edit:
#  export EDITOR=emacs
#  crontab -e
# The current file contains exactly one line (and ends with a newline):
# 0 11 * * * /home/rvl2/d/asldata/bin/jsrvr.chk
#
# Things that did not seem to work:
#  * Trying to detect using grep "java" | grep "asldata", because all processes use "asldata"
#  * Trying to detect when the bash file is running using grep "jsrvr.start"
#    (Even with the use | grep -v "grep")
#
#

# Check if server is alive, restart if necessary

PID=`ps -Af | grep "java -classpath .:/home/rvl2/d/asldata/" | grep -v "grep"`
LOG=/home/rvl2/d/asldata/JDBCServer.log

if [ ! -n "$PID" ]; then

## Pre-Apr 2008 version (replaced by the jsrvr.start call)
# java JDBCServer > /tmp/JDBCServer.out 2>&1 &

    /home/rvl2/d/asldata/bin/jsrvr.start > /tmp/JDBCServer.out 2>&1 &
    date=`/bin/date '+%a %b %e %T'`
    echo "$date: Server down.  Restarted it." >> $LOG
else
    date=`/bin/date '+%a %b %e %T'`
    echo "$date: Server up." >> $LOG
fi

# Check if mysql is alive, restart if necessary

PID=`pgrep "mysqld"`
LOG=/home/rvl2/d/asldata/JDBCServer.log

if [ ! -n "$PID" ]; then
    /usr/local/libexec/mysqld --datadir=/home/rvl2/a/mysql > /tmp/mysqld.log 2>&1 &
    date=`/bin/date '+%a %b %e %T'`
    echo "$date: mysqld down. restarted it." >> $LOG
else
    date=`/bin/date '+%a %b %e %T'`
    echo "$date: mysqld up." >> $LOG
fi

The script for starting the ASL Server is

 /bin/jsrvr.start

#!/bin/sh
cd  /home/rvl2/d/asldata/ASLdatabaseSearch/server;
java -classpath .:/home/rvl2/d/asldata/public-web/mysql-connector-java-3.1.10-bin.jar JDBCServer