CA SystemEDGE User Guide › Examples Using State Management › Reconfigure Extension Scripts Through SNMP

Reconfigure Extension Scripts Through SNMP

These scripts allow you to ping an arbitrary system using an extension script that you can reconfigure remotely using SNMP. Therefore, it is no necessary to edit sysedge.cf or any other custom script. You can set or change the name of the system you want to observe by using SNMP SET from any MIB Browser or event snmpset utility provided with SystemEDGE. Reading the extension variable provides a string with ping information.

To reconfigure extension scripts through SNMP

1. Add the following line to the configuration sysedge.cf file and restart SystemEDGE:

   extension 31 octetstring readwrite '/opt/CA/test/ping.sh' (UNIX, Linux)
   extension 31 octetstring readwrite 'c:\test\ping.bat' (Windows)
   

2. Copy the script (ping.sh, ping.bat) into the directory that you specified in the extension directive.
3. Enter a read request without setting up a ping target:

   C:\SystemEDGE\bin>.\snmpget -o 1.3.6.1.4.1.546.14.31.0
   1.3.6.1.4.1.546.14.31.0 Ping target must be set first
   

   An error message appears.

4. Set my-sles3 as the system which you want to ping:

   C:\SystemEDGE\bin>.\snmpset -c private -o 1.3.6.1.4.1.546.14.31.0 -s my-sles3
   1.3.6.1.4.1.546.14.31.0 my-sles3
   

5. Ping the system by reading the variable:

   C:\SystemEDGE\bin>.\snmpget -o 1.3.6.1.4.1.546.14.31.0
   1.3.6.1.4.1.546.14.31.0 my-sles3 is alive
   

The script checks that the extension has index 31. However, this check is technically not required and can be removed, so that the extension script can be assigned to any index.

The scripts ping.bat and ping.sh stores the configuration information in a temporary file.

Ping script for UNIX and Linux

#!/bin/sh
#
# ping.sh example extension script 
#
# A simple example script for the SystemEDGE agent extension group.
# This script implements a "Ping" SNMP MIB variable whereby
# Sets to this variable indicate what system should be pinged
# and Gets to this variable cause the Ping to occur and the 
# output to be returned as an OctetString.
#
# For reference, the following are passed as parameters by the SystemEDGE
# Agent. They are not used in this script.
# 
# The Extension Group Leaf Number
LeafNumber=$1
# The SNMP Operation: GET, GETNEXT, or SET
Operation=$2
# The value if a SET Operation
SetValue=$3

# determine which ping program to use
OSNAME=`/bin/uname -r`
OSTYPE=`/bin/uname -s`

if [ "$LeafNumber" = "31" ]; then

   # setup who we should be pinging
   if [ "$Operation" = "SET" ]; then
      echo $SetValue > /tmp/sysedge.ping.target
      echo $SetValue 
   fi

   if [ "$Operation" = "GETNEXT" ];  then
      Operation="GET"
   fi

   if [ "$Operation" = "GET" ]; then
      if [ ! -f /tmp/sysedge.ping.target ]; then
         echo "Ping target must be Set first"
         exit 0
      fi

      case $OSTYPE in
        Linux)
		/bin/ping -c 1 -q -n `/bin/cat /tmp/sysedge.ping.target`
		;;

        HP-UX)
		/etc/ping `/bin/cat /tmp/sysedge.ping.target` -n 1
		;;
        AIX)
		/etc/ping -c 1 `/bin/cat /tmp/sysedge.ping.target`
		;;
	SunOS) 
		/usr/sbin/ping `/bin/cat /tmp/sysedge.ping.target` 2
		;;
  
	*) 
	      case $OSNAME in
		6.*)
		  /usr/etc/ping -c 1 -q -n `/bin/cat /tmp/sysedge.ping.target` 

		  # IRIX ping is very annoying since it doesnt appear you can get
		  # one-line output indicating if the machine is alive or not alive.
		  # If we were trickier shell programmers, we'd catch the output
		  # and only echo the last line.
		  ;;

		5.*)
		  /usr/sbin/ping `/bin/cat /tmp/sysedge.ping.target` 2
		  ;;

		4.*)
		  /usr/etc/ping `/bin/cat /tmp/sysedge.ping.target` 2
		  ;;

		*)
		  echo "Cant determine ping command for system " $OSNAME
		  exit 0     
		  ;;
	      esac
	esac
   fi
fi

Ping script for Windows

@ECHO OFF
@rem ping.bat example extension script 
@rem
@rem A simple example script for the SystemEDGE agent extension group.
@rem This script implements a "Ping" SNMP MIB variable whereby
@rem Sets to this variable indicate what system should be pinged
@rem and Gets to this variable cause the Ping to occur and the 
@rem output to be returned as an OctetString.
@rem
@rem For reference, the following are passed as parameters by the SystemEDGE
@rem Agent.
@rem 

@rem The Extension Group Leaf Number
set LeafNumber=%1%

@rem The SNMP Operation: GET, GETNEXT, or SET
set Operation=%2%

@rem The value if a SET Operation
set SetValue=%3%

@rem Which ping command should we use
set PING=%SystemRoot%\system32\ping.exe

@rem We store our target in the "environment" for future use
@rem using variable SYSEDGE_PING_TARGET

if not %LeafNumber% == 31 goto fi

   @rem if set, we want to ensure there is a value,
   @rem then store it away, then echo the value to STDOUT
   @rem so as to not confuse extension code
   if %Operation% == SET if !%SetValue%==! goto error
   if %Operation% == SET @echo set SYSEDGE_PING_TARGET=%SetValue% > %TMP%\pingtgt.bat
   if %Operation% == SET echo %SetValue%
   if %Operation% == SET goto fi

   @rem Run the script to recover the target name
   call %TMP%\pingtgt.bat
   if !%SYSEDGE_PING_TARGET% ==! goto error

   @rem echo pinging %SYSEDGE_PING_TARGET%
   %PING% -n 1 -w 250 %SYSEDGE_PING_TARGET% > nul

   if ERRORLEVEL 1 echo %SYSEDGE_PING_TARGET% not alive
   if not ERRORLEVEL 1 echo %SYSEDGE_PING_TARGET% is alive

:fi
goto exit

:error 
echo Ping target must be set first

:exit
rem cleanup because command.com is really pathetic, sigh
set PING=
set Operation=
set LeafNumber=
set SetValue=