Monthly Archives: February 2015

How to convert an OVA virtual machine to VHD

Today I received a virtual machine OVA file exported from VMware, I needed to import this into Apache CloudStack where XenServer was the hypervisor.

To do this I first needed to convert the OVA/OVF to VHD, this post covers how it’s done.

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How to test network connectivity with telnet

This post is a follow on from my post last week regarding how to install the telnet client. The telnet client is simple yet extremely powerful in helping us gain a quick idea of where a problem may lie with TCP connectivity, it’s one of my first go to tools to use when testing a network connection to a server.

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How to enable the telnet client in Windows 8.1

By default the telnet client in Microsoft’s Windows operating systems is disabled, this is unfortunate as it is an extremely useful tool which can be used for testing TCP connectivity to external hosts on a specified port.

This is great when you’re trying to troubleshoot network connectivity problems, for example, say we have a web server which should be listening on port 80 to serve HTTP traffic but we are not able to load a web page, by using telnet to connect to the web server on port 80 we can verify the connectivity.

It may be that the connectivity is fine but there is a problem with the web server, or that the web server is stopped and the port is not listening at all, for instance. With telnet we can get a better understanding of what’s going on.

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Monitoring multiple back end Nagios/Icinga servers with Thruk

Thruk acts as a central web interface allowing you to monitor multiple backends such as Naemon, Nagios, Icinga and Shinken via the Livestatus API. I had some difficulty getting it connecting to my back end servers so here are the steps I took to get it done. By the end of this guide you should be able to add your back end monitoring servers into Thruk, we’ll cover adding an Icinga server in this instance however the steps will be very similar for a Nagios server, given Icinga is a Nagios port.

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