Free Infrastructure Monitoring Tools

By | October 10, 2013

I’m always on a lookout for good monitoring tools. I like to automate monitoring and alerting requirements on my Application Serving environments. I’ve tried number of these tools over the years for IT Application monitoring, Performance monitoring, IT Infrastructure monitoring and Network monitoring. Obviously some tools are better than others. As they say “you get what you pay for”. Best tools of the trade are not free and free tools leave you wanting more.
Many tools are free only for trial period or free versions are provided are not full feature versions. Many small IT shops need such tools can not afford to pay hefty licensing fees. All the monitoring tools listed below will suit small business owners as they will be actually use them for free.

Nagios Core

Nagios needs no introduction to Network and IT Infrastructure Administrator all over the world. It is perhaps the most famous Infrastructure monitoring tool used. Nagios Core is totally free to download and use with no restrictions and no catch. Only thing you will need is spare is time to install plugins, configure them and get them going based on your specific requirement.
There are paid versions and product support available for Nagios XI and Nagios Fusion.
Nagios UI does not look very attractive out of the box and it will not do what you need OOB. But there is virtually nothing that it can not monitor (Applications, Websites, network traffice, routers, switches, queues/queue depths ….), mainly because it relies heavily on the community and custom plug-ins. There many Administrators who just use Nagios core with custom add ons/plugins and it meets all their monitoring requirements, with some skills, time, efforts.
Most Admins like Nagios because is highly configurable, open source and tweak-able. Most organizations like Nagios because its free. However there are some people out there who would advise caution against using Nagios like this Gartner Blog. As you can see from comments on that blog that there are many people opposing views presented in that blog. But it is worthwhile to note that such veiws are not uncommon, specially among upper management in the organizations which have had not so pleasant experience with Nagios setup in their shops in the past.

One more drawback is that Nagios Core installation is not available for Windows. There is a Windows variation available called Nagwin. It is created by company called iTeF!x and they provide a basic no-frills version for free. They claim that Nagwin is compatible with most of the Plugins developed originally for nagios.

In summary, if your monitoring and alerting requirements are small and simple, or you have Admins who know their way around, then Nagios is perfect fit for you.


Let me start with this disclaimer : Splunk is not free for every one. But Splunk is noteworthy for the fact that it offers fully featured version for free to any one (even for commercial purposes) as long as the data you are indexing (read : collecting) is less than 500 MB per day.If you have a small set up to be monitored then it’s a suitable tool for you. Even with medium sized setup, if you choose the Apps wisely and tune them not to generate heaps of data (as they do, out of the box) ,then you can still be under 500 MB per day limit and use Splunk for free.

Splunk has many out of box features and add-ons (called Splunk Apps) targeted as specific OS, Domains, Applications etc. For example, App for monitoring Websphere Application Server, Windows App, Exchange Server App etc. It also comes with OOB capabilities to store, index and query data and It does a fantastic job in those areas. Reporting and altering are fairly easy to setup. Graphics are very cool. So you can get your application or Infrastructure monitoring set up in small amount of time wth Splunk.

You wil still need to spend some time and effort to set up monitoring to meet your specific requirements, but the time, effort and skill level required to do this are much lesser than Nagios. Splunk tries to be open and give power to community and lets user tweak it and create Apps. Thus it sits somewhere between black box and open source. For example till recent versions of Splunk, the capability to generate pdf reports was only available on Linux installations of Splunk (or by provisioning a Linux Server to do the job)

PRTG Network Monitor

PRTG Network Monitor is a network infrastructure monitoring tool by Passeler AG. Again it is a paid software, however There is a full feature copy available for free as long as you can keep your sensor count below 10. Sensor is PRTG terminology for each type of data you want monitored (per source) for example if you want to monitor weather 2 switches, 2 routers and 6 servers in your network are up or not – you can use PRTG for free.

The tool is aimed at network infrastructure monitoring specifically and not at application monitoring in the traditional sense. It has great out of of box features. Unlike Nagios and Splunk , who just has Web UI, PRTG has web UI, Desktop Application, Android and iOS Apps. On the downside PRTG Network monitor can be installed only on Windows.


I’ve also done a bit of reading about following tools. These also seem quite useful based on user reviews, demos and documentation. However I’ll right about those when I get a chance to play with them.


Zenoss Core


So there, there you have it – My take on full featured free Infrastructure Monitoring tools.

3 thoughts on “Free Infrastructure Monitoring Tools

  1. Jonah Kowall

    There are loads of other good tools out here I would put into your list in terms of doing the low cost monitoring Paessler does. There are also lots of Nagios clones which are good and commercially supported.

    1. Sarang Post author

      Thanks John. You are right – there are quite a few good free tools available. My aim was was to start with those which I’ve personally used. I’ll be adding some of the others to the list.

  2. Daniel

    I’m not sure your “if your monitoring and alerting requirements are small and simple” bit is right.
    If you have a small and simple environment, setting up Nagios to monitor it is overkill.

    Get Spiceworks or perhaps something even simpler like Simon from Dejal. Free or inexpensive tools for small environments.

    If you’re committing to learning Nagios, make it worth your while. The steep learning curve may not be worth it if your environment is too small.

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