Use Bash Script to Monitor The Status of Service

When you manage multiple servers it’s sometimes impossible to stay ahead of the various administrative tasks, which is why automation is so important.

If you’re working on a linux based server and want to monitor the status of a service, here is a quick an easy way to automate that process.

#!/bin/bash
# Script to find if a service is running

for i in ossec-monitord ossec-logcollector ossec-integratord;

 do ps auwx | grep -v grep | grep $i >/dev/null 2>&1 ;

   if [ $? = 0 ];

    then

     echo `date “+%Y-%m-%d %H:%M “`”$i Running…”;

    else

     echo `date “+%Y-%m-%d %H:%M “`”$i not running…”;

fi;

What we did above is create a simple loop looking for three distinct services:

  • ossec-monitord
  • ossec-logcollector
  • ossec-integratord

Those three services are assigned to the i variable, and that variable is then passed into the grep query here:

ps auwx | grep -v grep | grep $i >/dev/null 2>&1 ;

What we’re also doing above is cutting out any grep inquiries, because if you were to run a grep command it will show as a process as shown here in red:

root@server:~/scripts# ps auwx | grep ossec-logcollector

root      1260  0.0  0.0   4876  1784 ?        S    May19   0:03 /var/ossec/bin/ossec-logcollector

root     29353  0.0  0.0  14428  1116 pts/0    S+   20:59   0:00 grep –color=auto ossec-logcollector

By cutting out the grep request you see this response:

root@server:~/scripts# ps auwx | grep -v grep | grep ossec-logcollector

root      1260  0.0  0.0   4876  1784 ?        S    May19   0:03 /var/ossec/bin/ossec-logcollector

This is important because this   if [ $? = 0 ]; is looking for the grep exit value of 0, which states:

EXIT STATUS
    The grep utility exits with one of the following values:

    0     One or more lines were selected.
    1     No lines were selected.
    >1    An error occurred.

With this selection, if you run the grep and there are no service running it would still find the grep service itself. It’d give you a false positive response.

The echo command then prints the status of the service:

echo `date “+%Y-%m-%d %H:%M “`”$i Running…”;

It passes each argument through the loop. If the service is found to be running it prints:

2020-05-19 18:27 ossec-monitord Running…

2020-05-19 18:27 ossec-logcollector Running…

2020-05-19 18:27 ossec-integratord Running…

Leave a Reply

Your email address will not be published. Required fields are marked *