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Scripts for Automating Network Systems Checks
Victor Feng, April 2008
Introduction
In my previous article, Scripts for Automating
System Checks, I described how to check logs, check for new patches, and check for disk errors automatically on a single system
using the checkmessages,
checkpatch, and checkdisk scripts. If those scripts find anything wrong, the system sends email to notify the system administrator.
This tech tip provides five scripts for automating the same system checks on networked systems that run the Solaris 9 or
10 Operating System. If these scripts find anything wrong, email is sent to the system administrator.
In order to send out email, sendmail has to be running. By default,
sendmail runs on a system, but in some situations, sendmail is disabled, for
instance, when another email system (such as Sun Java System Messaging Server) is using port 25. To handle such situations, you need to copy the necessary information for the systems in question to a shared place, and process the information using a system that has sendmail running.
For the purposes of this tech tip, assume that host02 does not have sendmail, and
it has an NFS shared folder, /report, that is writable by both host01 and
host03. Also assume that host03 does not have sendmail, and that
host01 has sendmail and is going to process the information for both
host02 and host03. If there is anything wrong with either host02 or host03,
host01 will send email to notify the system administrator.
Source Code for the Scripts
Here are the five scripts this tech tip provides:
The checkmessages_net script checks the logs on the hosts. If anything wrong is found, the script
sends email to the system administrator. This script should be scheduled to run daily using cron.
Here's the source code for the host02_checkdisk
script. Please rename it so it has a .sh extension instead of a .txt
extension, and then install it on the machine that you want to be host02before
you run the checkdisk_net or checkmessages_net script.
Here's the source code for the host03_checkdisk
script. Please rename it so it has a .sh extension instead of a .txt
extension, and then install it on the machine that you want to be host03before
you run the checkdisk_net or checkmessages_net script.
The checkpatch script checks for newly available patches for a system. It, too, should be run daily.
The checkmessages_net script on host01 first processes its own
/var/adm/messages file. Then it processes the messages file of
host02.
Before you run the checkmessages_net script, you need to copy the log file of
host02 from /var/adm/messages to the shared location,
/report. Use a cron job to do this on NFS server
host02, as follows:
Also, before running checkmessages_net, assign your email address to the
variable MAIL_RECEIVER.
The checkdisk_net Script
When host02 runs the host02_checkdisk script, the
host02_checkdisk script creates a new file, host02_diskerror.txt, in the shared
folder, /report, if a disk error is found.
Then the checkdisk_net script on host01 sends out email based on the
existence of the host02_diskerror.txt file, and then it deletes the file.
Therefore, the host02_checkdisk script should be run before the
checkdisk_net script. For example, on host02,
you could use the following cron command:
30 23 * * * /home/<username>/bin/host02_checkdisk
On host01, you could use this cron command:
31 23 * * * /home/<username>/bin/checkdisk
Similarly, for host03, the host03_checkdisk script needs to be scheduled
to run before the checkdisk_net script is run on host01:
On host03, you could use this cron command:
30 23 * * * /home/<username>/bin/host03_checkdisk
In a similar way to checking for disk errors, you can check for newly available patches for host02
and host03, as described next.
Some new patches might be not related to your system. If you do not want to be notified about them again, you can add them
to the script using lines similar to the following:
After you patch your systems, you should remove such lines from the script so that you are notified if new, related patches
become available.
The checkpatch script checks security patches. But you can modify the script to check for all
available patches by changing missings to missing.
Again, you can use cron to run the script daily.
A Sun Online account is now required to download patchdiag.xref. Therefore, before
running the checkpatch script, assign the user name and password for your Sun Online account to the
USERNAME and PASSWORD variables in the
checkpatch script.
Synchronizing the Time Clock of the Servers
As you can see, the time clock among the servers needs to be synchronized. You can do this through the Network Time Protocol (NTP).
If you are not familiar with NTP, here is a fast way to set it up.
1. Pick one server as the NTP server, for example, host01, and do the following:
Note: It is best to choose the server on which sendmail is running.
# vi /etc/inet/ntp.conf
server 127.127.1.0
Or, you can replace 127.127.1.0 with your authoritative DNS or Microsoft Active Directory server.
2. On the other servers, for example, host02 and host03, do the following:
# vi /etc/inet/ntp.conf
Server host01
3. Start the NTP service on each server, starting the service on the NTP server first:
On the Solaris 9 OS:
# /etc/init.d/xntpd start
On the Solaris 10 OS:
# svcadm enable ntp
From now on, host02 and host03 will have the same time as
host01.
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