Today I will be writing about setting up an Ubuntu instance on the Amazon AWS cloud and running a Java web application on it. We are working on a hobby project that has its back-end written in Java. The app back-end was first hosted on Heroku but due to some issues, we decided to move it to Amazon AWS. I was given the responsibility to set up our server. This was the first time I had an opportunity to work with Amazon AWS. But it turned out to be quite fun.

I bought a Dell Inspiron laptop recently which came with Ubuntu 14.04 preinstalled. Something I noticed with the factory Ubuntu 14.04 image was that some of the settings were tweaked to work better with the laptop. One fine example was that the laptop display would automatically dim when I switched to laptop battery from the power supply. It would again go back to full brightness once I connected the adapter back.

Being primarily a Java developer using Eclipse IDE, there are two things I always look for in any IDE - content assist/code completion and syntax checking/highlighting. While the latest version of Eclipse (Neon) has made a lot of improvements over the previous versions in terms of the JSDT plugin for Javascript developers, it's far from perfect. The syntax highlighting works upto some extent but the content assist is still very primitive if at all useful.

I have mostly used Ubuntu and Debian-based distributions till now which means the other side of the Linux world, where the RHEL based distributions reside is still a grey area to me. Recently I needed to install CentOS server in VirtualBox to test something out. But soon I found that it's a little cumbersome to work in the VirtualBox vm window because I can't copy/paste texts normally to/from the VirtualBox as I can do in Terminal and I can't cycle through the open windows in my guest machine using Alt+Tab when I am using the vm. So I decided to ssh to the CentOS guest from the host machine and work from the host Terminal instead.

I have used Oracle Virtualbox before. It has an easy and intuitive UI, supports all the features I needed and is open-source. But this time I decided to use another widely recognized virtualization solution on Linux, qemu, along with kvm.

First of all, let me give some brief idea about qemu, virt-manager and kvm. Qemu is the software which can be used to install and run a guest OS on top of the actual OS to put it in a very simple way although it's much more powerful than that. It can be compared to Virtualbox except that qemu itself does not have a UI, instead it's a command line utility. Virt-manager is some thing that provides a GUI to qemu. Together virt-manager and qemu can be thought of as the Virtualbox. On the other hand, kvm is the Linux kernel module that can help qemu execute the virtualized instructions directly on the CPU which can improve the performance greatly. This is to be kept in mind that qemu can run even without kvm but the speed will be much slower.