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We work with a variety of technologies. Blog posts relating to this work are found in this category.

CatN is proud to have six Certified System Administrators in Red Hat Enterprise Linux OpenStack

One of our six certified developers, Jorge Serrano, who has successfully passed the rigorous course in Red Hat Enterprise Linux OpenStack, talks about the hands-on training. It has given him practical experience which will enable him to improve our customer experience. Congratulations Jorge and everyone, well done!

Having so many Red Hat experts in-house now makes us one of the most qualified OpenStack companies in the UK!

To see what other people who took the course with Jorge have to say watch this short video:


Platform as a Service billing explained

In this video Joe Gardiner explains why PaaS is important for reducing cost and waste when compared to dedicated hosting and in particular, infrastructure as a service.

IaaS is held up as an excellent solution for saving money by outsourcing IT requirements to the cloud, however there is still a lot of waste and complexity which can be solved by adopting PaaS. This is a growing market and the majority of IT market analysts agree that PaaS is set to grow over the next few years – Gartner in particular expect the PaaS market to be worth $2.9 billion in 2016.

Five reasons SMEs are not moving to the cloud

Despite the growth in adoption of cloud services there are still plenty of businesses resisting a move. We see a lot about large enterprise having concerns about security and sovereignty of data but what are the reasons SMEs are giving for not adopting cloud?

I have put together some responses to some of the concerns I have heard raised by SMEs.

  1. What will happen if the cloud company I use goes out of business?

    The key thing here is the way an application is developed. It is important to develop an application in a way that allows it to be moved to any cloud provider (PaaS or IaaS) if a serious problem occurs. As the industry standardises it becomes increasingly easy to do this through the use of deployment tools such as Puppet and Ansible. If you find yourself relying on specific features that only your current provider offers then you’re doing it wrong.

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95th Percentile Billing – An Explanation

As a hosting provider, one of the most important components of our services is the ability for customers bandwidth to be burstable. Customers will usually commit to a committed data rate (CDR) each month as their baseline level of traffic, enabling CatN to capacity plan our network and customers to be assured of a minimum level of service provision.

In addition to CDR, customers expect CatN’s network to be capable of allowing usage to exceed the CDR for short periods without incurring the cost of paying for blocks of additional CDR which may not be utilised the remainder of the billing period.

Most hosting providers, CatN Included, use 95th percentile billing as a method to charge customers fairly for the bandwidth consumed while remaining flexible to spikes in demand.

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Racing to launch with ArduSat


A few months ago CatN became the sole platinum sponsor of the ArduSat satellite project on Kickstarter.

ArduSat is an Arduino powered satellite which allows the general public to design and run their own experiments in space. There’s a huge range of sensors and options on the device so part of the fun is seeing what crazy experiments people come up with.

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Generating a CSR with Apache OpenSSL


CatN have been offering hosting services for a number of years now, with one common request from our customers being the ability to provide and install SSL Certificates for their hosting products. The first stage in the process is to generate an RSA Private Key and and CSR, which can be used by an SSL Authority to generate you an SSL Certificate.

We will use the Apache OpenSSL toolkit to generate both the RSA Private Key and Certificate Signing Request. The following instructions require that OpenSSL is installed on your server, as this is a common package it should be available on most of the major distributions through their package installer.

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Working with Virtual Machine images

CatN engineers spend a lot of time working with virtual machine images. We have put together this useful list of commonly used commands and procedures to help you get started on your next project.

For simplicity we assume to work with VM images created using the shell script, as explained on my previous post “Automated CentOS Virtual Machine Image Creation”.

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Add a virtual storage device to a Virtual Machine

Following our previous article about resizing virtual machine images, we now look adding an additional storage device to an existing VM. If instead you wish to extend the existing VM storage volumes, please consult the article “Resize a CentOS Virtual Machine Image“.

For simplicity we assume that the VM image you wish to extend has been created using the shell script, as explained on my previous post “Automated CentOS Virtual Machine Image Creation“.

The file-based virtual storage device acts as a virtualized hard drive for virtualized guests and its creation is quite quite straightforward.

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Resize a CentOS Virtual Machine Image

Following our series of articles about virtual machine images, we now look at a common problem faced by system engineers – what happens when you run out of disk space on your virtual machine? This guide addresses this issue and explains how to expand a CentOS Virtual Machine image, resizing any partitions contained within.

We assume that the VM image to resize has been created using the shell script, as explained on my previous post “Automated CentOS Virtual Machine Image Creation“. This is because the resizing script ( assumes details about storage volumes that rely on the having be used. In any case all the steps are illustrated here so you can adapt the commands to your needs.

The shell script is part of the CentOS-KVM-Image-Tools project that you can clone on your machine using the following command:

git clone git://

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Automated CentOS Virtual Machine Image Creation

This article shows how to create a CentOS Virtual Machine (VM) in unattended mode using a shell script and illustrates the main steps and options to reproduce the process manually.

The following script and commands will create a base image that can be used to deploy multiple nodes from a system like Ansible to define roles for each node. It is very useful for creating clustered virtual environments such as the vCluster stack.

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