PING LINUX

Last year, when I was assigned a role to administer the test lab for a project, I was quite excited about it. Almost 130 linux based machines, all variants and distributions known to me were available in the lab. Initially it was fun, but later I find it difficult to cope up with its requirements. A sysadmin job is far different from testing. I had number of questions coming to my mind related to linux, networking, installation, backup, etc. How does a DHCP work? Can we have few machines with static IP and few with DHCP? What is a domain controller? How simple can be samba.conf? What’s difference between DNS and DC?

To fiind answer to all these questions, I need to experiment a lot. I need an isolated network of machines with one server and few clients. Unfortunately my projects’ test lab was already short of machines. So experimenting there was out of question. So my mind started searching for an alternative and I found it right on my laptop. Virtualization was the answer to all my questions.

I had worked on VMWare Workstation in my last project but it was at a very basic level. We just had different versions of Windows images installed over it and I simply used to power it on & off. But this time my requirement was quite demanding. And to my surprise the same VMWare software had everything I needed, but just with a small problem – VMWare requires lot of RAM to run each image. And my plan was to run at least 3 to 4 machines at the same time.

I looked at my system, a Core2Duo with 1 GB of RAM. Damn! with just 1GB of RAM how many linux machines would I be able to run in parallel? Still I decided to move ahead. Initally I installed RHEL 5.2 as my server with 256 MB of RAM allocated for it. Thankfully RHEL works smoothly on 256MB. And now I’m left with 750 MB of RAM, out of which minimum of 500MB I’ll have to keep free for my host OS i.e. resource hungry – Windows Vista Home Bsic. I got my laptop pre-installed with windows vista which I should have downgraded to Windows XP but just because of my laziness I continued to use it as received.

Now I’ve just 250MB of RAM to install my client linux machines. I started searching for a very light weight linux and to my surprise there were many. Most popular ones are Puppy Linux and Damn Small Linux. This distribution’s name itself are sufficient to indicate what they are meant for. I liked the DSL, it just needs 50MB of HDD space to install and what about RAM? Well, it can run smoothly even on 64 MB of RAM! Wow! that was more than what I could ask for. But DSL has more than what was I was asking for. It has everything one can think of in a OS, a GUI desktop, ftp server, samba server, nfs server and the list doesn’t end here it can run webserver as well. Pheeew! so much in a 50MB linux. This is the power of open source. Somebody decided to make the linux compact and he peeked into the source code and here we have the Damn Small LInux.

Now I couldn’t wait to create my network, so I installed 3 more virtual machines with DSL and 64 MB of RAM reserved for each of them. Actually you dont have to install it 3 times. In vmware you can install it once and then create the clones of it. Now only part remaining was the network. So in vmware you can create a team of virtual machines that act as a network connected via a ethernet switch. So problem solved!

Now I had a 4 machine test lab at my disposal and nothing coming in betweeen me and my experiments. And all this on a 1GB RAM laptop. So when somebody asks me, where did you tried this particular thing? I reply it as….well I’ve a test lab at my home. And the natural reaction is ‘A linux test lab at your home, really?’ and I reply it as not really …. but virtually!