Linux for IBM i: Introducing Linux to IBM i people

Linux on i is a cheap, easy and very powerful operating system. This introduction to Linux for the AS/400 walks you through some history and resources including where to get Linux. The advantages of the OS are described, along with a brief discussion of what is different about Linux on iSeries.

The IBM i is a great platform. Not many of you out there will argue that point. It's solid, robust and very powerful. Part of that power is just that power or the hardware that we now call Power. The operating system (OS) is nothing unless it has rock-solid hardware to run on. So part of the IBM i's stability is the hardware. Another fine example of a powerful OS that runs on Power is AIX. The problem is that not everything needs an...

IBM i or an AIX partition. Sometimes, you just need a file and print server or maybe a DNS or mail router. Of course you could do this all on Windows, but that gets really expensive and it does not run on Power. So, what do you do? Linux on Power: It's easy, cheap and very powerful, much like its AIX cousin.

The next hurdle is the OS and how it works. If you have never seen Unix or Linux, your first few weeks can be painful. So lets take this one step at a time and talk about Linux, you the Administrator and what to do with your new best friend.

What is Linux?
We don't have time to cover end-to-end what Linux is, but I do have time to catch you up with the last 15 years or so of Linux and why we are talking about it now.

Long, long ago in a dark damp room at AT&T some geeks made a thing, an open source thing called Unix. It was really crappy but over time it got better, much better, and now we have a few different kinds of Unix. So now you are asking how does Linux fit in? Linus Torvalds created Linux out of basic boredom and because he was a geek and he needed a project to work on. There are all kinds of stories behind where Linux came from, but in the end we all have to thank one dude, Linus.

So where is Linux today? Great question. Today, Linux is an open sourced OS that is free to everyone. You can download it, install it and run it for free. But there has to be a catch, right? There is: free is only free if you don't want support and want to learn Linux the hard way. You have to patch your own kernel and really get to know your Linux OS. Therefore, some companies "sell" Linux. Because of how Linux is licensed, they can't actually sell it. But they can sell services around Linux. Some of these include Redhat, and SUSE. They will give you Linux if you offer to buy the services and support. (I don't like it but that is the way it goes.)

So where do you get the free versions? Skip ahead if you wish. But first, I want you to understand a little about Linux so that you're not in the dark.

Here is what Linux.com says Linux is:

Linux is an operating system that was initially created as a hobby by a young student, Linus Torvalds, at the University of Helsinki in Finland. Linus had an interest in Minix, a small UNIX system, and decided to develop a system that exceeded the Minix standards. He began his work in 1991 when he released version 0.02 and worked steadily until 1994 when version 1.0 of the Linux Kernel was released. The kernel, at the heart of all Linux systems, is developed and released under the GNU General Public License and its source code is freely available to everyone. It is this kernel that forms the base around which a Linux operating system is developed. There are now literally hundreds of companies and organizations and an equal number of individuals that have released their own versions of operating systems based on the Linux kernel. More information on the kernel can be found at our sister site, LinuxHQ and at the official Linux Kernel archives. The current full-featured version is 2.6 (released December 2003) and development continues.

So now we all have a pretty good idea what Linux is and where it came from. The future of Linux is up to you.

What is open source?
Open source, after so many years, is still a buzz word in IT. We all like the idea of the source being free and open. I know I do -- even if I can't read all of it. I just like it that you can read all of it if you want to, and that people do. Open source was started some time about and the thought is supported by the idea based on the GNU.

Open source software does many things for the people who run it and view it. It is software you can see and touch: you can read the source code, you can edit it, and if your changes are significant and other people want them then you have the right (and the responsibility) to give them back to the community. That in a nutshell is the simplicity of open source. Isn't it beautiful?

There is a saying about open source: "FREE" as in speech, but not FREE as in beer.

From GNU.org:

GNU, which stands for Gnu's Not Unix, is the name for the complete Unix-compatible software system which I am writing so that I can give it away free to everyone who can use it. Several other volunteers are helping me. Contributions of time, money, programs and equipment are greatly needed.

So, now we have two free things: free software by way of open source, and the Linux OS, which is at it's core, free!

Do you have to open source all your programs for Linux?
The answer is no; however, it would be a nice thing for you to do, but you don't have to. It's your code and you don't have to share it with anyone. But in the spirit of open source and what is going on you might want to open it to everyone. Just because it runs on Linux does not mean you have to open up the source. WebSphere is a prime example. It's great software but unless I work at IBM on that project I will probably never see the code that makes it work.

Great open source projects for Linux

Click on the image for larger version. Image courtesy of Netcraft.com.

Apache HTTP Web server is still one of the top open source projects. It can run on many operating systems and is very dependable. The HTTP server that runs on the System i is very similar to the Apache variant.

SAMBA: File and print sharing for the rest of the world. While we know little to nothing about the code behind Microsoft's file and print sharing, or any of the security risks, we can of course look at the source and run SAMBA on our Linux servers. It's a very quick way to leverage the power of Linux in your datacenter. While a Windows server will cost you thousands of dollars, and that is just the cost of the OS, and Linux/SAMBA server will really only cost you the price of the hardware and your time and effort, but in the end you walk away knowing you have saved your company money over time and it will be more efficient.

Sendmail: Most Linux distributions come with some type of mail server available in the install. While we all like IBM and would love to just hand them over money for Lotus Domino and Notes clients, sometimes that is not a viable option for small companies who only need a mail service and need it fast and cheap. Sendmail is one of the most popular options in Linux-based datacenters. It's relatively easy to set up and you can even overlay it with a browser-based mail client and not spend a dime for a large mail solution. Why should you, you're going to do it all with the System i and Linux right?

Where can I get Linux?
I get this question a lot and most of the time I just hand them a CD out of my bag. But if you don't meet me in person, I will direct you to a download and a little CD burning of your own.

You could do it the hard way and download the Kernel and then compile it, but in the end you will be bald and cussing like a sailor, so let me recommend and few other alternatives that may be more appealing. Also, you can order Enterprise editions of Redhat and SUSE for a price. You're going to need the "Linux for Power" to get it to run on the System i.

Opinion: I am ashamed of IBM for selling copies of Linux on Power, you would think they would give them away, but they don't. Your company ends up having to pay for them and you have to order them from IBM.

But lets say you want to run Linux on your Intel or AMD based servers. You're in luck. You can download any type of Linux you like. Here is a short list of distributions you may want to consider.

Operating System Name URL
Redhat Fedora Fedoraproject.org
Novell OpenSUSE Opensuse.org
Canonical Ltd. Ubuntu server Ubuntu.com
Slackware Linux, Inc. Slackware Slackware.com
Debian Project Debian GNU/Linux Debian.org

There are many others not listed here, but you can find them. I am a big fan of Ubuntu and think it's going to be a pretty solid OS for most anyone who tries it.

Can you get Linux pre-installed on a server so you can just drop it into a rack and it be done? Of course you can. I have done it many times and my favorite place to shop is System76.com. They will build you a custom pizza box server with Ubuntu. I think this is a great way to start. Make sure you tell them I sent you -- they will be tickled pink.

What about all that free software?
So you have Linux installed and you want more free software for your new Linux server, where are you going to get it? There are always repositories that you can connect to in order to download the software you need. Redhat and SUSE both use RPM packages to install stuff, and Ubuntu used .deb files (DEB). They are a great way and an easy way to install extra software you may need without too much fuss.

Why would I use Linux over some other server or desktop operating system?
That is a question for all time, but the answer is rather simple. While the "other" operating systems most companies use are pretty good, in the past three years the Linux offering has really become stable and very usable from a GUI standpoint. While the "other" company is not losing money by any means they are not making anyone happy charging them all that money, and for what? Most companies could move to Linux for desktop and server-side applications. This would take a little effort, but in the end it would be a huge cost savings and (in my opinion) make the world a better place.

What helps organizations move to Linux?

  • Low cost and relatively no licensing fees
  • Reliability
  • Performance
  • Windows security issues
  • Recommended by technical staff
  • Need an alternative to Windows
  • Development tools are widely available through the internet
  • Ability to modify the source code to meet specific needs
  • Fast patches and bug fixes by a global community
  • Meets company standards and requirements
  • Measurable ROI
  • Company has an open source philosophy
  • Need an alternative to Unix

So why are so many companies choosing to go with Linux over Windows for server and desktop needs?
I think the answers are pretty simple, Linux is really pretty inexpensive compared to the cost of owning a Windows license. There are those out there who say the cost is higher, but when you install Windows you have to install the base OS which is a very bloated install and then you have to run your application over it. This is not the most optimal way to run a datacenter. Much like the System i, you can choose what programs you have running and where. Windows does not afford you these options nor does it allow you to be in control of your OS. The reason we as System i fans flock to the i5/OS is because it's very customizable and dependable. The same (and even more) can be said for Linux. While Linux is open, i5/OS is not. Also, another reason to add Linux to you infrastructure is to gain performance and lower costs.

Automating Linux is very simple, much like it is on the System i. The same can not be said for the other guys. You can script Linux and then drive things from that script to email, the web or other logs. The power of Linux is that everything is customizable.

What is different about Linux on the System i?
If you are used to running Linux on a little server, running it on the System i is very similar. You will be able to run the Linux server in it's own independent partition much like you do now with i5/OS. There are logically separated systems and they don't depend on your i5/OS installations to run. These are separate instances of an OS running in its own layer on the Power architecture and being managed from the HMC.

Processors: Like any other OS on the system you will be able to assign your new Linux partitions a minimum of .10 of a CPU or as much as you like. I would of course give it at least four CPUs just for fun, but according to IBM, .10 will get Linux up and running.

Memory: I/O and Virtual I/O. You can have both. For example, if you have only one Ethernet card in your System i, you can of course share that with all your partitions by making it virtual and the Linux partitions will share it with the i5/OS partitions. You may also have AiX partitions that need it also -- the System i can handle it.

ABOUT THE AUTHOR: David Vasta is the Lotus Notes Administration Team Lead over North America at Atlas Copco. He has 17 years of data center and iSeries experience working in companies such as IBM, REAL and Cingular. He writes a regular blog at System i blogger.

This was first published in August 2008

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