Test Plan Charlie: 41000 Linux Servers on One Box

There was a test done many years ago by David Boyes, an engineer working out of Virginia.  The test was simply to run as many Linux servers on one IBM zSeries mainframe – and to keep adding them until something broke.

The test hit the limit at 41,400 Linux servers – and nothing ever “broke.” This project was widely reported at the time, though it seems to be forgotten now. However, the test caught my fancy. That’s a lot of Linux machines.

As was mentioned, this report was widely reported: Linux Journal had an article on 1 June titled The Penguin and the Dinosaur from Adam Thornton.  That same day, Daisy Whitney authored an article, Linux on Big Iron – possibly in Datamation. Scott Courtney (the Technical Editor for Internet.com) wrote S/390: The Linux Dream Machine on 23 February and wrote It’s Official: IBM Announces Linux for the S/390 on 17 May. What really stands out?  All of these articles reporting on the S/390 and on Test Plan Charlie occurred nine years ago, in 2000.

Scott Courtney followed his articles up with an interview with David Boyes in 2001.

There is one more thing about David Boyes: following Test Plan Charlie, he went on to create Sine Nomine Associates and showcased OpenSolaris running on the IBM zSeries in November of 2007 – with attendant press releases from IBM. Certainly, David is not one to sit idle – and is a figure to contend with in the IBM zSeries arena. IBM has, since the original announcement nine years ago, pushed Linux on zSeries with vigor.  One irony: Test Plan Charlie was part of a study for an IBM customer that was deciding whether to use their existing S/390 or whether to use a new Sun set up.

There is even an open source IBM mainframe emulator called Hercules, which allows the rest of us to try it out and see what happens – even though you won’t be able to run under z/VM, as that is an IBM product.

Update: there was a nice set of updates about OpenSolaris on zSeries over on DancingDinosaur: Here comes (and goes) the Sun (12 April 2009) and Slow times for OpenSolaris on System z (21 July 2009).

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User Interface Design: the Command Line

The command line is not immune from user interface design. Especially with the concept of language, one has to choose carefully the options and names and orders of the things in order to make things work just the way the user expects them to.

If the program is too different, people will be tripping over it all the time. The UNIX tar command comes to mind as one that failed here: options (or “actions”) specifically did not start with a dash. Likewise, UNIX find also failed: if you didn’t include the parameter -print at the end, you saw no output: your find command found nothing! (In reality, it just didn’t report it.) Both of these errors have been rectified in the last several decades: UNIX find has an implied -print, and tar often will make the dash optional – which makes it work both the way it always did and the way it should have.

As an example of what seems to be a colossal user interface failure – including poor writing – consider these articles from Scott Remnant which are absolutely a gem (albeit from way back in February 2009). He wrote an article titled Git Sucks – which was then followed by a second and then a third – followed by yet another titled Revision Control Systems Suck.

What Scott is railing about is how hard these systems are to learn (he targets not just git, but also GNU Arch and Bazaar). From his standpoint, he finds these systems to be complicated and hard to understand.

He also points out (rightly) that the most common actions should be the simplest, and finds that with git these common actions are rarely ever simple. He specifically mentions reviewing the changes that someone else has made compared to his own – and says that there’s not a revision control system that makes it easy.

An example of how user interface design can be incorporated into things like the command line and even programming is this quote from an interview with Yukihiro Matsumoto, the developer of the programming language Ruby about his guiding principle in developing Ruby:

[It's] called the “principle of least surprise.” I believe people want to express themselves when they program. They don’t want to fight with the language. Programming languages must feel natural to programmers.

and later in the same interview:

In addition, Ruby is designed to be human-oriented. It reduces the burden of programming. It tries to push jobs back to machines. You can accomplish more tasks with less work, in smaller yet readable code.

Another example: I was just rereading my copy of The Humane Interface written by Jef Raskin. In it, he had a section titled Noun-Verb versus Verb-Noun Constructions (section 3-3, p. 59). This mirrors a problem I have experienced with some command line software in the past: the command wants an action as the first argument, and the object of the action second. I despised it enough that it was the genesis of my writing a wrapper for the command that reversed the order: object first, action second. Imagine my surprise to find my troubles validated right there in Raskin’s book.

There are many examples of command line programs doing wrong things, and of programs doing right things. One of the right things comes from HP-UX and its software management tools such as swinstall: if the program can use an X display for a graphical display, it will: but if not, it goes to a text display instead.

There are many such examples, of programs just doing what you need and leaving you to think about other things. I wonder what would happen if a company like Apple decided to tackle the command line – although, in a way, they did already. In MacOS X, consider the open command for instance… absolutely brilliant, which is in contrast to the open command sometimes found in other UNIXes (never standard).

One very important point to remember: “It’s only hard until you learn it” is not a valid excuse. The learning curve for a program should not be any steeper than it has to be.

Renaming a host (UNIX, OpenVMS)

Renaming a host is not, in general, a pleasant experience. The general requirement is that you must find everywhere that your hostname is specified and change it.

In OpenVMS, this can be an extensive process, and even require relicensing if you have licenses that depend on your hostname. It can also require rebooting of an entire VMS cluster if you miss changing a parameter. The full details are in the VMS FAQ such as this one (dated from 2001) from faqs.org or this one from HP (undated). Hoffman Labs has a copy from September 2006; there is information on changing a node name in section 5.7.

Not that in changing the OpenVMS hostname in a cluster, you must change the SCSNODE parameter (which changes the cluster node’s nodename). If you change the SCSNODE parameter, you must change the SCSSYSTEMID as well or the entire cluster will refuse to function until it is reconfigured. The cluster tracks the pairing between these two parameters, and if the pair changes, then the cluster stops working normally.

For UNIX in general, one way to do it is to go to the /etc directory as root and run a search:

$ su -
Password:
# cd /etc
# find . -type f -print | xargs grep -i myhost

After running this, change all of the instances of myhost that is found.

This is the way to change hostnames in Solaris, including Solaris 9 and Solaris 10. Debian and derivatives (including Ubuntu and Linux Mint) and HP-UX make it simpler.

In Debian, there is a file called /etc/hostname. This will contain the current setting of the hostname. Change this to your desired new hostname, then run the shell script /etc/init.d/hostname.sh.

In HP-UX, change to root and run the program set_parms with the hostname option:

# set_parms hostname

For all of these possibilities, the best thing to do is to reboot afterwards: this will test the new setup as well as change any in-memory hostname settings.

Changing a hostname is a drastic measure, and will include much in the way of system modification and updates. Changing the actual hostname is very likely only the beginning; there may be clients that are set up to contact the host, and any services that the server provided (e.g., NTP server, FTP server, web server, NIS server, etc.) will require reconfiguration on the clients to use the new hostname.

In summary, the very best thing to do is to get the name right in the first place.

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UNIX and OpenVMS Online Resources

It is possible to get free online access to UNIX or to OpenVMS; these can be useful in building up your experience on a platform when starting from scratch – or when a review is required.

One of the oldest public access systems in the country is the Super Dimension Fortress (or SDF as it is usually called). SDF offers free accounts, but does ask for US$1 to gain standard access. This isn’t because access is expensive, but because too many people have used the facilities for nefarious purposes (the process suggests that the new user is not a person who will strike and leave).

SDF runs NetBSD on DEC Alphas; this was driven mainly by security and stability. Previously, Stephen Jones, the proprietor, ran SDF using Linux on Intel for several years (which he describes as “the dark years”). BSDTalk had an interview with him back in 2006.

You could also try PolarHome – this shell provider provides access to hosts running Linux (Red Hat, Debian, SUSE, Ubuntu, or Mandriva), OpenVMS (Alpha or VAX), OpenBSD, FreeBSD, NetBSD, HPUX, IRIX, QNX, Solaris, Ultrix, AIX, Tru64, and OpenStep. Unfortunately it requires payment for shell accounts – again because of abuse. The payment is 10 units of your local currency or US$2, whichever is more – and this is per host as well. No other site provides this diverse of a selection.

For truly free UNIX shell accounts, one can try Grex, which is a more professionally-run system (Polarhome and SDF are sole proprietorships). Grex offers totally free shell accounts, but also has memberships (for people to help support the site). It is possible that Grex has the most users as well. Like the others, paid membership does have its privileges – but unlike the others, membership is mainly to provide support for Grex, rather as a security feature.

For OpenVMS, there is a very unique online shell provider: Deathrow Cluster. This is a cluster of three machines running OpenVMS 7.3 – one VAX, one Alpha, and one emulated VAX (SIMH) on a dual Xeon machine. This last is a perfect example of what can be done with an emulator, especially with SIMH which can emulate all manner of old Digital and IBM hardware. However, SIMH does not emulate the Digital Alpha, unfortunately. Like Grex, Deathrow provides completely free shell accounts; like SDF and Polarhome, it is (or appears to be) mainly one person’s purpose to keep it running with a lot of volunteer help.

Any of these will be good sources to keep your shell skills sharp – and in some cases, programming as well. They’re also good people to support; why not offer them some donations if you can?

Keyspan Drivers and Linux (Debian/Ubuntu/Mint)

The drivers for the Keyspan USB-Serial Adapter are in the mainline kernel (as of 2.6.x), as Keyspan notes. However, the drivers are (according to Keyspan) not in the Debian or Ubuntu kernels.

This is only partly true: Debian refused to use the Keyspan drivers due to their license; the fact that Keyspan drivers were missing from the latest Ubuntu kernels is a bug (#334285).

Since Linux Mint is based on Ubuntu, one can only hope that the kernel bug is fixed soon; I’d wanted to use my Keyspan driver with my laptop running Linux Mint 7.

NO PUBKEY errors from APT (Ubuntu Linux)

When you are using APT (the package manager for Debian and Ubuntu Linux), you might receive some NO PUB_KEY errors – warnings that no public key could be found for one software repository or another. You can keep on going without fixing these warnings, but in the interest of security you should fix the problem. It is rather simple, after all.

Firstly, if you are running Ubuntu, you can use the Ubuntu key server to help you fix this problem. The server uses the SKS Key Server software to provide this valuable service.

The method is to first import the key into GPG (GNU Privacy Guard) via the Ubuntu key server (or indeed, any other), and then import it into APT via the apt-key command:

gpg --keyserver subkeys.pgp.net --recv 0123456789ABCDEF
gpg --export --armor 89ABCDEF | sudo apt-key add -

In place of 0123456789ABCDEF put the tag given in the NO PUB KEY message, and then insert the code given in the response from gpg in place of 89ABCDEF for the export.

However: apt-key has an apparently little known command option that will pass options directly to gpg. Using this option (“adv”), the update of the key can be done in one step instead of two:

sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 0123456789ABCDEF

If you already have the appropriate gpg key – or can get it from an appropriate web site or FTP site – you can add it directly to your APT key ring using apt-key. For example, here is an example adapted from Google’s Linux Repository Configuration page:

wget -q -O - https://dl-ssl.google.com/linux/linux_signing_key.pub | sudo apt-key add -

One could just as easily use any other method to get the file that supported the given URL. Remember that you must add the key as root; it won’t work otherwise. If you have the file locally, this is sufficient:

sudo apt-get add somekeyfile.gpg

Hope this helps you.

Using Open Source in the Enterprise: Two Stories

This was interesting. Just recently MIT announced that they would be replacing their Cyrus IMAP infrastructure with Microsoft Exchange. The reason was that the IS Department wanted to offer Exchange – that is, they wanted to provide Microsoft Exchange services to their “customers” (students and faculty). Isn’t it ironic that it is none other than Carnegie Mellon, another educational institution, that maintains Cyrus IMAP? Many students are also upset, as they will no longer be able to use Pine for their email.

This news can be compared to the recent news from the London Stock Exchange: they are dropping their Windows-based trading system for one based on Linux. Of course, they didn’t go out of their way to choose one or the other: but the Windows-based system halted trading for an entire day; the exchange never stated exactly what the cause was, but information was that it was the trading system that was at fault. Now the CEO that brought in the trading system is out without any comment, and the first order of business for the new CEO is to dump the old Windows-based trading system. ComputerWorld has a nice article on it. This shows the reliability of Linux overall and suggests that the reliability of Linux should be a strong selling point.

Next time management starts suggesting replacing Linux with Windows – tell them the story of the London Stock Exchange. They are also not the only ones; go read the article.

SheevaPlug: a Tiny Computer for $99

This computer introduced by Marvell is very tiny, and very interesting.  Despite the fact that Marvell’s wireless chipset has been closed to open source developers, it appears that the Sheeva Plug computer is being released as an open product: running Linux on an ARM processor, it is now available for $99 as a pre-release developer’s edition. There is already a place for developers to congregate and for documentation and so forth.

LinuxDevices had a delightful article on the technical aspects of the SheevaPlug, and it is very enlightening.

What would I use such a computer for?  I would quite possibly make it into a NAS solution with OpenFiler or FreeNAS; make it serve IP addresses via DHCP; make it into a web cache like squid; or make it serve music with subsonic.

This is one beautiful box.  One drawback I see is that with the way it is configured, there is no way to get it off the wall and out of the way.  Too many boxes plug right into the wall, which means there is no place for another box to plug in.

Another deficiency, which is silently ignored in a lot of applications shown: there is only one network connection. For the system to be a router of any type, it needs to have multiple network connections. If a SheevaPlug is to be a wireless router – or a cellular router – or other similar configurations, it needs to have more than one network connection. With the USB connection available, this is possible – but only if the USB isn’t taken with something else.

One nuisance to note, like others of its ilk: it requires added peripherals, so the “tiny” box could expand to include an external hard drive, and external USB hub with its own AC plug, a bluetooth USB plug, a USB cellular modem, a USB network port, and two network cables. This is the curse of tiny electronics today: one day, all of these extras will be included in a box the same size, and the cabling will be history.

One disadvantage that no one seems to have mentioned yet: the box is not grounded.  That’s right: only two prongs – no grounding plug.  This is totally baffling to me: no ground?

Still, these are really minor disadvantages: I want one – or even two!

It would be interesting to consider the use of these in the enterprise (although they are specifically designed for the home). The biggest places I could see these used in the enterprise would be for testing purposes, and for disaster recovery. If you had one of these ready as a DHCP server and DNS server, one as a NIS server – perhaps a medium-sized enterprise could run off of these until the real servers are built and ready to go.

They could also be used to support people in the field: preconfigured, ready to run: demonstration systems, VPN end points, presentation systems, security test launching points… What else can you think of?

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Network Attached Storage (NAS)

Once you hear what a NAS appliance does, you might be tempted to think (as I did) what all the fuss might be about. But there are reasons for a NAS appliance, though a NAS isn’t for everybody.

Network Attached Storage is nothing more than a server with a pile of disks and a dozen different ways to access them. For most intents and purposes, the difference between a File Server of yesteryear and the Network Attached Storage of today is conceptually rather minimal.

NAS typically provides access to files via such methods as Windows shares, NFS, iSCSI, Appleshare and others.

So what does a NAS appliance provide that a NFS server does not? There are several benefits:

• Special purpose. Since the system is solely for the purpose of serving up files for users, there is no need for any other facilities except those that deal with its specified purpose. Thus, a lot of potentially vulnerable or unreliable code can be removed, and the speed and reliability of the system can be increased. Some systems do not come with a general purpose operating system of any kind, but rather a specially designed operating system for serving files alone.
• Extensive support. In many cases, since the system is specifically designed for serving up file storage, the innumerable variations of network storage protocols come supported out of the box.
• Ease of use. With the system designed to serve one purpose – and to provide the customer with the best possible experience – the system is generally made much easier to configure and easier to use than having to configure the varying servers and protocols independently.

There are two different NAS products that are the heavy-weights in the free and open source arena: FreeNAS (freenas.org) and OpenFiler (openfiler.com).

The most obvious difference between these two is their base (and their associated licenses). The base for FreeNAS is FreeBSD, and like FreeBSD, is licensed using the BSD license. However, OpenFiler uses Linux as its base, and is likewise covered by the General Public License version 2.

This week, I’ll focus on FreeNAS with the assistance of a book entitled Learning FreeNAS by Gary Sims and published by Packt Publishing.

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Ten Linux Applications You Must Have!

I read this article of Ten Linux Apps That You Can’t Do Without and was surprised. Why was I surprised?

I was surprised to see how little of the list I consider “must have” applications. Most of the applications I probably would never use, and would be quite happy without. Even the two stalwart entries from Mozilla, Firefox and Thunderbird, aren’t really must have applications.

Of course, this sets one to thinking – if those aren’t the Top 10, then what is? What are the Top 10 Applications you must have?

This is an interesting question – especially as I’m leaning toward using my MacMini more and more these days (but that’s a future topic).

1. BasKet. This is a very nice note-taking application, which provides for beautifully done notes with links, application launchers, hyperlinks to the web, and full color graphics et al.
2. Kontakt. This is a PIM that combines KMail, BasKet, KTimer, and many more into one single PIM. Very nicely done, and well worth using.
3. KMyMoney. This is quite possibly the most advanced personal budgeting tool for KDE, and it is very nice.
4. Thinkfree Office. There are some extremely capable office suites, such as KOffice and OpenOffice. However, only Thinkfree not only synchronizes with an online repository, but also provides a way to edit online as well as on other platforms.
5. Amarok. What’s productivity without some background music? Amarok is easy to use and provides all the capabilities you could hope for.
6. Zim. A personal wiki: empty your brain here!
7. KPDF. Why try to utilize a presentation tool when you can just create a PDF and use KPDF instead?
8. digiKam. Store your photos, tag them, and more.
9. KRDC. Access your desktop with this application, and work like you are at your desk.
10. Keep. Back up those files! Keep is simple enough to run every day and not get in your way. You won’t have any qualms about backing up if you use this tool.

What’s on your list?