{"id":1288,"date":"2014-12-11T00:00:12","date_gmt":"2014-12-11T08:00:12","guid":{"rendered":"http:\/\/192.168.3.4\/?p=1288"},"modified":"2018-01-09T06:49:50","modified_gmt":"2018-01-09T14:49:50","slug":"dual-camera-helmet","status":"publish","type":"post","link":"https:\/\/www.cloudacm.com\/?p=1288","title":{"rendered":"Cacti, RPi, and GPIO device readings"},"content":{"rendered":"

Introduction – CactiPi isn’t as hard to eat as you might think.
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In my earlier post<\/a>, the\u00a0RPi command and control features have been an excellent way to show capabilities. Webmin showed how complex admin tasks can be done graphiclly, without the need for a desktop environment. Smokeping was introduced, but not covered in detail. This tool is usefull in identifying host availability on the network, but it doesn’t go much further.<\/p>\n

This is were Cacti comes into play. This is primarily a graphing utility based off of Tobi Oetiker’s MRTG and RRDTool<\/a> efforts. I have been using these tools on systems\u00a0longer than the existance of the RPi and Arduino platforms combined. Cacti is interesting due to its support of third party plugins. This is what makes the tool take on a different form and extends it to different disciplines.<\/p>\n

Here is a description, that I found at\u00a0http:\/\/openmaniak.com\/cacti.php<\/a>,\u00a0of what Cacti is.<\/p>\n

“Cacti is a web based PHP\/MySql graphing solution using the RRDtool engine. \u00a0<\/em>Classically, it can graph network bandwidthes with SNMP. But in fact, a lot of different graphs can be done with snmp, shell or perl scripts…<\/em>Cacti’s strength lies in the fact that it can be installed and used incredibly easily… On the very active Cacti forum, you can share “Cacti templates” with other users which can can save you a lot of time. You can very easily add plugins to the Cacti too enabling the possiblility to integrate other free tools like ntop or php weathermap..<\/em>.<\/em>RRDtool is developed using the “C” programming language and it stores the collected data on “.rrd” files.<\/em>The number of records in a “.rrd” file never increases, meaning that old records are frequently removed. This implies that one obtains precise figures for recently logged data, whereas figures based on very old data are mean value approximations. By default, you can have daily, weekly, monthy and yearly graphs.”<\/em><\/p>\n

Since the hard work of Cacti and getting it installed on RPi have been ironed out, lets dive in.<\/p>\n

Purpose – Don’t reinvent the wheel, just learn how to use it.
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In this section, I will go through what Cacti is and how it can be used on a RPi. I’ll also cover the installation and setup of Cacti on the RPi. Cacti comes bundled with features to allow it to monitor and graph metrics like processes, cpu usage, network traffic, and latency. I’ll also cover how to setup Cacti to poll and graph SNMP devices using non standard OID values. Leastly, I’ll cover how to use Cacti to poll and graph devices attached through the RPi GPIO header. The ability to quantify values using the RPi will be worthwhile. I’ve used VMs to perform these tasks as a solution for network diagnostics. The VMs are a point of vulnerablity and are also dependent on the host they run on. The RPi is well suited to run along side the VMs to add a layer of reliablity without high costs.<\/p>\n

Detail – Having a way to look back at where you’ve been.
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The steps to install Cacti on the RPi are available here<\/a>. \u00a0You can see that the steps aren’t too involving. \u00a0I had success going through the prodecures. \u00a0However, it is worth mentioning that it is good practice to\u00a0included the sudo command at the beginning of each string.
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