Using an SMS Server to Provide a Robust Alerting Service for Nagios
I was able to get everything running in a day or two, but I did have to resolve several issues as part of the installation. I also discovered several problems that required changes to the Perl script. Therefore, it's important to test the scripts.
You can run the check_smsfinder.pl and sendsms.pl scripts on the command line to view their output directly. For example:
% /usr/local/nagios/libexec/check_smsfinder.pl \ -H 192.168.1.50 -u nagios -p secret OK: GSM signal strength is 100.0% - \ model: SF100-G - \ firmware: 1.31|loginID=1607132337 strength=100.0%;40;20;; % /usr/local/nagios/smsack/sendsms.pl \ --noma -H 192.168.1.50 -u nagios -p secret \ -n 14155551212 -m 'this is a SMS from nagios' "this%20is%20a%20SMS%20from%20nagios" to 14155551212 \ via 192.168.1.50 send successfully. MessageID: 37
The smsack.cgi script is a little harder to debug than the command-line scripts, but the usual Apache log files access_log and error_log are useful in that they will contain the HTTP response codes when the CGI is invoked by the iSMS. You also can use the method described below under “Network Capture” to look for problems with the CGI script.
In many places within Nagios, the Perl script and the iSMS device contain debugging information. Knowing where those are will help you with your installation.
The iSMS can send helpful debugging messages to a remote host via syslog. The Nagios server would be an ideal destination for the messages, as all logging can be consolidated in once place. The remote syslog host is specified in the iSMS Web GUI. The iSMS syslog messages use the LOG_LOCAL0 facility. I added a local0.* /var/log/isms entry to my /etc/syslog.conf file to capture all messages. The log file will record all SMS messages sent and received by the iSMS, for example:
Nov 23 09:27:59 smsgw MultiModemiSMS modem: sentlog: [SENT TO] : 14155551212 : [MSG] : this is a SMS from Nagios
The log also contains any authentication failures. This is useful because the check_smsfinder.pl and sendsms.pl scripts authenticate themselves to the iSMS every time they run.
The iSMS has a concept of an “Inbox” for SMS messages received from mobile users and an “Outbox” for SMS messages being sent out from the iSMS. You can examine these boxes via the iSMS Web interface to find out whether a message actually was received or transmitted.
Nagios logs to the file nagios.log, which is typically found in the /usr/local/nagios/var directory. You can use this log to verify that Nagios is generating an alert for a problem and that a command has been used to send an SMS (notify-host-by-sms):
 HOST NOTIFICATION: epearce-sms;mailserv2;DOWN;notify-host-by-sms;CRITICAL - Host Unreachable (192.168.1.250)
The Nagios log also will show the results of smsack.cgi running after getting the “ACK” back from a mobile user:
 EXTERNAL COMMAND: ACKNOWLEDGE_HOST_PROBLEM;mailserv2;1;1;1;14155551212; Acknowledged by 14155551212 at 09/11/17 15:29:57 ACK PROBLEM mailserv2> is DOWN /11-17-2009 15:28:21/ CRITICAL - Host Unreachable(192.168.1.250)
The smsfinder scripts log to smsfinder.log (also in the Nagios var directory). This file will contain debugging information for the sendsms.pl and smsack.cgi uses of the script. The lines containing “SMSsend” show the status of sendsms.pl when it is being run by Nagios. For example:
2009/11/19 12:55:39 SMSsend: "PROBLEM...mailserv...is...DOWN...CRITICAL..." to 14155551212 via 192.168.1.250 queued successfully. MessageID: 14
Lines containing “SMSreceived” and “SMSverify” will show the progress in parsing any acknowledgement SMS messages received by the smsack.cgi script:
2009/11/12 09:15:41 SMSreceived: username=nagios&password=secret&XMLDATA= <?xml version="1.0" encoding="ISO-8859-1"?> <Message Notification> <SenderNumber>14155551212</SenderNumber> <Message> ACK PROBLEM HostAlert mailserv2 192.168.1.250 /AllServices is DOWN /11-12-2009 09:11:46/ CRITICAL - Host Unreachable (192.168.1.250) </Message> <Date>09/11/12</Date> <Time>09:15:36</Time> </Message Notification> 2009/11/12 09:15:41 SMSverify status = ACKed - ACCEPTED: From=14155551212 Received=09/11/12 09:15:36 Status=ACK Host=mailserv2 Service=AllServices MSG="ACK PROBLEM ... Host Unreachable (192.168.1.250)"
Practical Task Scheduling Deployment
One of the best things about the UNIX environment (aside from being stable and efficient) is the vast array of software tools available to help you do your job. Traditionally, a UNIX tool does only one thing, but does that one thing very well. For example, grep is very easy to use and can search vast amounts of data quickly. The find tool can find a particular file or files based on all kinds of criteria. It's pretty easy to string these tools together to build even more powerful tools, such as a tool that finds all of the .log files in the /home directory and searches each one for a particular entry. This erector-set mentality allows UNIX system administrators to seem to always have the right tool for the job.
Cron traditionally has been considered another such a tool for job scheduling, but is it enough? This webinar considers that very question. The first part builds on a previous Geek Guide, Beyond Cron, and briefly describes how to know when it might be time to consider upgrading your job scheduling infrastructure. The second part presents an actual planning and implementation framework.
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- The Firebird Project's Firebird Relational Database
- Murat Yener and Onur Dundar's Expert Android Studio (Wrox)
- SUSE LLC's SUSE Manager
- Managing Linux Using Puppet
- My +1 Sword of Productivity
- Non-Linux FOSS: Caffeine!
- Google's SwiftShader Released
- Doing for User Space What We Did for Kernel Space
- SuperTuxKart 0.9.2 Released
With all the industry talk about the benefits of Linux on Power and all the performance advantages offered by its open architecture, you may be considering a move in that direction. If you are thinking about analytics, big data and cloud computing, you would be right to evaluate Power. The idea of using commodity x86 hardware and replacing it every three years is an outdated cost model. It doesn’t consider the total cost of ownership, and it doesn’t consider the advantage of real processing power, high-availability and multithreading like a demon.
This ebook takes a look at some of the practical applications of the Linux on Power platform and ways you might bring all the performance power of this open architecture to bear for your organization. There are no smoke and mirrors here—just hard, cold, empirical evidence provided by independent sources. I also consider some innovative ways Linux on Power will be used in the future.Get the Guide