Opsview Core is a network monitoring software application. It solves the challenges of monitoring modern IT and network systems. It is a drop-in replacement for Nagios Core, with full support for its plugins and 100% compatibility. It is easy to install and configure and is ideal for monitoring applications networks, and Windows, Linux, and Unix servers. VMWare, KVM, Xen, and Microsoft Hyper-V are supported, and Amazon EC2 and other cloud services can be monitored. It works with Opsview Mobile to allow you to monitor your systems on the go.
It's All Good is a simple service monitoring framework to make it easy to monitor various services on a server. Its API is dead simple, and a handful of modules are already available for common things like disk usage, checking that SMTP is running, SSL certs are valid, or a page's contents. It can easily be used with a service like Pingdom so that you can monitor your servers' health with only 1 alert (which you can get for free). It's small, compact, fast, and loads nicely on most mobile devices including your iPhone or Android device.