Virtualization

Recently, we had the User-Mode Linux suite out of Debian, which included user- mode-linux, user-mode-linux-doc and uml-utilities package. We are happy that we were able to bring it back into the archvie quick, and hope to maintain it active.

For many who may not know about UML, here’s a discription from its website:

User-Mode Linux is a safe, secure way of running Linux versions and Linux processes. Run buggy software, experiment with new Linux kernels or distributions, and poke around in the internals of Linux, all without risking your main Linux setup.

User-Mode Linux gives you a virtual machine that may have more hardware and software virtual resources than your actual, physical computer. Disk storage for the virtual machine is entirely contained inside a single file on your physical machine. You can assign your virtual machine only the hardware access you want it to have. With properly limited access, nothing you do on the virtual machine can change or damage your real computer, or its software.

Most of the use cases mentioned here are achievable with Containers today. The big difference UML provides in, is with a separate kernel. UML is an implementation of Linux as an architecture of Linux itself. It supports x86 and x86_64 architecture. And given that it is the port of the kernel, you can do many of the tests and experiments of the regular kernel, safely inside a confined UML environment. As with other virtualization implementations, the limitation comes in if you are working on physical hardware.

We just pushed VirtualBox 5.0.0 into Debian Experimental. It should land up on your mirrors very soon.

Since this is a major release, we are looking for some testing and feedback. If you use VBox, or have your business depend on it, please give it a test. For details about what is new in 5.x, please check out the [release announcement](http://www.oracle.com/corporate/pressrelease/oracle-vm- virtualbox-5-070915.html)

One of the great things about Debian is the wide range of kernels it supports can run. This gives the user the flexibility to not spend time on the common userland stuff. For example, most apps, package management and system admin tasks are common across all Debian platforms.

These platforms may not be optimal at par to Linux, but still, choice is good.

For long, I had used Debian GNU/Hurd, only on a KVM hypervisor. Recently being involved in VirtualBox maintenance, I’ve almost beeing using VirtualBox for all my virtualization tasks. So it was time to try out Hurd on VirtualBox.

Linux has improved many many things over the last couple of years. Of the many improvements, the one that I’ve started leveraging the most today, are Control Groups.

In the past, when there was a need to build a prototype for a solution, we needed hardware.

Then came the virtualization richness to Linux. It came in 2 major flavors, KVM ( Full Virtualization ) and Xen ( Para Virtualization ). Over the years, the difference of para vs full, for both the implementations, is almost none. KVM now has support for Para-Virtualizaiton, with para-virtualized drviers for most resource intensive tasks, like network and I/O. Similarly, Xen has Full Virtualization support with the help of Qemu-KVM.

Lately, for my day job (to be more efficient for the time I spent), I am required to use Windows, back again. :-)

It is great to be back. By back, I mean using Windows for some of the workflows. All these years, I’ve been using Linux based tools (Debian, Kontact | IceDove, Konq | Chromium | IceWeasel etc) to get my job done. It is great to try back Windows for some of the workflows.

I recently ended up acquiring a Windows 7 Professional license. While I rarely have a need for Windows, that one rare instance is important. Many of the bank’s web interfaces are tightly dependent on IE. I do have a copy of CrossOver but that doesn’t help much. Most times, IE crashes when trying to render pages. Must be having some OLE dependency.

So I convinced myself to install Windows7. For my banking needs and also to catch-up on how that platform has been doing. From my limited usage, my current impression has been that Windows 7 is a great revive. [passwordless] sudo is conceptually implemented into Windows 7. I’m not sure how good that would be given that most users would have the tendency to just click on ‘Yes’ without paying attention to the pop-up. Anyways…..I installed Windows 7 onto one of my spare partitions to get the full experience (than doing it in a VM image).

In my previous blog entry, I mentioned about not being able to simply configured networking for the Guest VMs. I feel that area is still unimplemented properly by the GUI wrappers available for KVM/QEMU.

There is a good utility VDE2, which can work great for all your networking needs for the Guest VMs. But unfortunately none of the GUI wrappers (Qemulator, QtEmu, Qlauncher) are handling it.

The simplicity of vde is amazing. Here’s what all you need to do:

So Yesterday, I was finally confident enough to uninstall VMWare from my laptop.

Thanks to the richness of virtualization technologies which are present in Linux (2.6.22) now.

I’ve always liked to explore different operating systems (not distributions really) to see what interesting features they implement differently. BSDs being one, Solaris being the other. But sometimes it really was difficult for me to try them out.

Reason:

• The current machine that I have apart from my laptop is a very old box with 64Mb of RAM and a 750 Mhz Intel Processor
• This box is primarily used for building my cusotmized kernels to run on my laptop.
• This box serves as a file server.
• This box doesn’t have a head.

I also own a Dell XPS M1210 laptop with a pretty good configuration.

First,

DISCLAIMER: I ’m not a guru, I’m just a learner. So there might be a chance that the whole article might be fundamentally wrong.

I thought of this because I use P2P network a lot.

On my laptop, which is the repository of everything I have, it is necessary for me to make sure that it is secure enough.

To firewall it I use the single rule from iptables: