Automated System Monitoring

Josh Malonejmalone@nrao.edu

Systems AdministratorNational Radio Astronomy Observatory

Charlottesville, VA

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https://blogs.nrao.edu/jmalone

WHAT IS AUTOMATED MONITORING?

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Automated Monitoring Workflow

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Monitoring Packages: Open Source•

• Opsview Core

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• Core

• Pandora FMS

• Naemon

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• Captialware ServerStatus

• Sensu

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All Trademarks and Logos are property of their respective trademark or copyright holders and are used by permission or fair use for education. Neither the presenter nor the conference organizers are affiliated in any way with any companies mentioned here.

Monitoring Packages: Commercial• Nagios XI

• Groundwork

• PRTG network monitor

• CopperEgg

• WhatsUp Gold

• PRTG network monitor

• op5 (Naemon)

• Sensaphone (IMS 4000)

• Statseeker

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All Trademarks and Logos are property of their respective trademark or copyright holders and are used by permission or fair use for education. Neither the presenter nor the conference organizers are affiliated in any way with any companies mentioned here.

What can monitoring do for you?• Spot small problems before they become big ones• Checklist when restoring from a power outage• Learn about outages before your users do• Gives you better problem reports than users• Problems you might never spot otherwise

• Failed HDDs in RAIDs• Full /var partitions• Logs not rotating• System temperature rising

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With Monitoring

•dhcp out of leases•dhcp server down•dns server not responding

•ethernet switch down• ISP link down / saturated

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Without Monitoring

“The Internet’s down - fix it!!!”

With Monitoring

•connectivity issues•web server down•apache not running•web server disk full• server load too high

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Without Monitoring

“ZOMG! Our web site is down! O Noes!!!”

What can monitoring do for you?• Capacity planning

• Performance data can generate graphs of utilization• RAM, Disk, etc.

• Availability reports - CAUTION• Easy to generate -- even easier to generate wrong• Make sure your configurations actually catch problems• Will also include problems with Nagios itself :(• If you’re going to quote your availability numbers (SLAs,

etc.) make sure you understand what you’re actually monitoring.

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ENVIRONMENT MONITORING

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Environment Monitoring• Temperature• Smoke• Water• Humidity• Motion• Door / closure• Mains power

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Environment Monitoring• Sensaphone IMS-4000• Connect sensors to

measure desired metrics• IP-based “Nodes” can

connect remote sensors• Wireless sensors available• Notification via POTS line

and voice dialer as well as email

• SNMP support

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Use my plugin w/ Nagios!

Environment Monitoring• ServersCheck

• Temp, Humidity• Wireless (2.4GHz)

• NetBotz• Temp, humidity, smoke, water,

vibration, doors, cameras

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NAGIOS

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• Open source host / service monitoring package

• “Nagios Ain't Gonna Insist On Sainthood”

• Originally released in 1999 as “NetSaint”

• Available in 2 versions: Core and XI

• Nagios Core: Open-source, freely available

• Nagios XI: Commercial• Free license for up to 7 hosts• Available as source installer or VMware appliance

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Nagios

Nagios Architecture

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What’s a plugin?• Plugins actually run the service or host checks.• Each plugin monitors a different type of service• Data from plugin is communicated to Nagios using a (very)

simple API• Plugins can also report “Performance Data” (perfdata) to be

graphed or tracked• Requires a perfdata add-on (or Nagios XI)

• Plugins can be written in any language• Perl plugins can run using Nagios’s embedded perl

interpreter for increased performance

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Where to Monitor a Service?

Host ping

TCP port 443

SSL handshake

HTTP return code

Page load time

Page content

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Is server host alive?

Is Apache listening?

Is SSL functional?

Is the page found?

Does page load quickly?

Is it the right page?

Custom Plugins

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• Nagios can monitor anything you can write a script to check• Simple API: just write text to stdout and exit with a value• You can write plugins in ANY language you choose!

• bash, python, tcl, expect• perl (Nagios has embedded perl interpreter for speed)• C, C++

• Huge collection of plugins available at:http://exchange.nagios.orghttps://www.monitoringexchange.org

• Be wary of some community plug-ins!• Test first!!!

Performance Data• Metrics about the state of the service• Can be used to generate graphs showing trends, etc.• Performance data processing requires some external add-on

like PNP4Nagios

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My Plugins Framework• https://github.com/48kRAM/nagios-plugins• Perl• Net::SNMP

• Plugin for APC Smart-UPS,

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Agent-less vs Agent-full ChecksAgent-less

• No agent installed on the monitored host

• All check plugins run on the monitoring server

• Service to be monitored must be network-accessible

• Default mode of Nagios

Agent-full

• Must install agent on server to be monitored

• Check logic runs on monitored host

• Can access services non-network services

• SNMP can be a powerful agent for checks

• Server-specific agents

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USING NAGIOS

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About Nagios Replacements

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When Nagios went commercial, the “open-source community” decided that it needed not one, not two, but three replacements for Nagios: Icinga and Naemon (forks of Nagios) and Shinken (a drop-in replacement). Most linux distros are now shipping one or more of these compatible replacements rather than the official Nagios Core. Not a single distro I checked is shipping Nagios 4.

Either Shinken, Naemon or Icinga should work the same as the material covered here, but I have only briefly tested Icinga and have not tested Shinken or Naemon at all.

Overview

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Navbar Main window

The Tactical Overview• Displays overview of monitored services and hosts• Shows if

• Any services / hosts have notifications disabled• Any services / hosts are flapping• Active / passive checks enabled / disabled• Warning / Critical / Okay breakdown

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The Tactical Overview

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Services View

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Host summary Service summary

Click on Services - Critical

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Host and Service Groups• Organize services or hosts into groups by function, etc.• Can disable alerts, schedule downtime, etc. on whole group• Can show availability report for a whole group

• Group services by desired reporting capability• Groups get a unique URL so you can send a single link to

check on a group of hosts• Great for PHBs!• Also great for delegated IT departments

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Service Groups

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Acknowledging an Outage• Click on service name (or hostname) that has the problem• Under “Service Commands”

• Click “Acknowledge this service problem”• You must enter a comment about why you are acknowledging

the problem (i.e., “Bob is working on it”)• Click “Commit”

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Acknowledging an Outage

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Click Here

Acknowledging an Outage

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SMS pages• Configure a contact to use

an email-to-sms gateway• Some carriers require an

MMS gateway to process the ‘From’ address

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Add-ons to Consider• PNP4Nagios - Performance data graphing• NConf - Web-based configurator for Hosts, Services, etc.• NagiosQL - Web-based admin tool for Nagios• NDOUtils - Export data from Nagios to MySQL

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THANK YOU!

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Previous talks available at:

https://blogs.nrao.edu/jmalone/talks/