Shell Programming and Scripting

Hi,

In that case, if Nagios is already monitoring the load of your server...what is it you're hoping to achieve by running your own separate load monitoring script ? What does it do differently from what the Nagios check does, and would it not be possible to amend the Nagios check to do whatever you want so you only have one single check ?

Hi

we need to get email alerts and monitor our app with out any delay

you don't need a temp file. How about this for the trailing portion of your script:

Code:

CPU_LOAD=`sar -P ALL 10 1 |grep 'Average.*all' |awk -F" " '{print 100.0 -$NF}' |cut -d \. -f1`
if [ $CPU_LOAD -gt $THRESHOLD ]; then
    echo "CPU notification on $HOSTNAME is ${CPU_LOAD}% " `date`  | mail -s "Check CPU usage on $HOSTNAME `date`  " $ALERT
fi

Moderator's Comments:

edit by bakunin: fixed lost QUOTE-tag

I can change and test

Moderator's Comments:

edit by bakunin: fixed missing QUOTE-tag

Hi,

(Edit: forgot to include the date in the mail)

Here's a version of your script that's as streamlined as I've been able to make it:

Code:

#!/bin/bash

hostname="`/bin/hostname`"
date="`/bin/date`"
load="`/usr/bin/sar -P ALL 10 1 | /usr/bin/awk '$1 == "Average:" && $2 == "all" {print 100-$NF}'`"

threshold="90.00"
recipient="unixforum@localhost"
subject="Load alert on host $hostname"
body="Load is $load, date is $date"

if [[ "$load" > "$threshold" ]]
then
        echo "$body" | /usr/bin/mail -s "$subject" "$recipient" >/dev/null 2>/dev/null
        exit 1
else
        exit 0
fi

Again in my own local tests this worked fine, but then so did your original. You may need to amend paths to things like sar, awk, etc (it's always a good idea to use fully-qualified paths in scripts that will be run via crontab).

Hope this helps.

Hi vgersh99,
Good catch on the -gt versus > test. Without that change, it could miss reporting that the CPU load was 100% (but it still shouldn't have caused any false high load reports). Note that the script we were shown in post #4 didn't have this bug.

Note the code marked in red above. I agree wholeheartedly that the temp file is not needed (and suggested removing it back in post #5 in this thread), but the temp file is removed before it is appended to in the code you're questioning, so that shouldn't have caused any false high load reports either (assuming the code shown to us in post #9 is the actual code being run).

Hi anil529,
Why don't you also make the changes I suggested in post #5 in this thread (where I also proposed getting rid of the temp file) and get rid of two unneeded processes that are adding unneeded load to the system you're trying to monitor?

If you decide to try drysdalk's suggestion instead, at least note that you must change the:

Code:

if [[ "$load" > "$threshold" ]]

to:

Code:

if [[ "$load" -gt "$threshold" ]]

as noted above by vgersh99 to keep from missing reports if the load reaches 100%.

If we add monitoring scripts on the server will it increases server load
say 5 scripts running all time ?