Once it was completed, I looked around (grepped around) for the output file and was dismayed to discover that there weren’t any. After tinkering around for about an hour, I finally figured out that you can request shared libraries be built by providing an option to the configure script:

./configure --enable-shared

Shortly thereafter, I got the shared library version I needed and was on the road again. Just a useful tip which I hope can be of help to someone.

For those who might not know, MapReduce is a novel data-processing system developed by Google for internal usage and described in their publication entitled MapReduce: Simplified Data Processing on Large Clusters. For the enlightened out there, it should be clear that the name and mechanism are derived from Lisp’s map and reduce functions. In any case, though Google’s implementation is proprietary, there have been several implementations based on their paper both written in and geared toward a variety of programming languages. Unfortunately, none of these are available in the Debian repositories. In all fairness, Debian does include CouchDB which uses map and reduce functions for generating views. However, it’s not a solution aimed at sorting and processing huge amounts of data, though it is an interesting and capable piece of software.

So, to try and get things moving, I have filed three Debian RFPs (Request For Package) for a few seperate MapReduce implementations.

• Hadoop – Probably the most well-known of the Free/Open Source implementations. Includes a distributed filesystem (HDFS), scaleable distributed database (HBase) and tools to get you going from start to finish. Hadoop is written in Java though it can interoperate with other languages (Scala, too). It’s a top-level project of the Apache Software Foundation and licensed under the Apache License 2.0 – http://hadoop.apache.org
• Skynet – A MapReduce implementation written in Ruby. It’s designed to be fault-tolerant and distrubuted, just like the big boys. Originally written for use at Geni.com and licensed under the MIT License – http://skynet.rubyforge.org/
• Disco – Though the implementation is itself written in Erlang, thus providing excellent distributed fault-tolerance, Disco jobs can be written in Python. It was developed as an in-house tool for rapid data analysis at Nokia and they seem to be quite keen on it. Disco is licensed under a modified BSD License. Page at http://discoproject.org/ and code at http://github.com/tuulos/disco/tree/master

Ok, there might be a few objections to my choices. Why did I leave out neat projects like GridGain, FileMap and BashReduce? Well, for starters, GridGain is another Java implementation that doesn’t seem (at least to me) to have the same momentum Hadoop does. FileMap and BashReduce, while novel, useful and fascinating, are not designed for use in networked environments and are therefore unsuitable for cluster situations. So then whey not MapSharp? Well, primarily because of all the Debian Mono debates going on right now (Gnome’s fail!) . I’ve done work in C# and it’s got some neat features but cool stuff doesn’t and will not ensure that users are not liable from patent litigation.

Also, it seems like those RFPs have some mistakes, so if anyone figures out how to edit them, let me know so I can clean them up.

It worked out for the better as I had been sort-of-almost-definately been meaning to rebuild that particular machine anyway. Since the hardware is fine (though the disk might die, soonish), I reinstalled Debian Squeeze from a nightly-build installer and took the opportunity to change a few things in my network’s setup.

The first major change I made was to switch all the machines on my network to use debtorrent instead of apt-proxy which had been behaving unreliably. In particular, apt-proxy had been randomly hanging after a few transfers, thus causing the machines using it to be unable to upgrade their packages or install new ones. So, in an attempt to fix it and give a little back to the community, I have installed debtorrent on my main server and configured my other machines to use it. So far, it’s working quite well, the download speed is rather fast and it caches packages so that other machines may download them.

The next thing I changed was to take a few more security measures than I normally do. I have been using various known strategies for some time now but a fresh start seemed like a good opportunity to tighten things up with a fresh install. First, the Securing Debian manual is required reading for any sysadmin and I re-read over it while waiting for lengthy processes to finish. Since my machines are already behind a firewall that only lets SSH traffic in and then only through to the server in question, my revised security checklist goes something like this:

1. Remove all RPC services: sudo aptitude --purge remove portmap nfs-common
2. Remove root login option (especially since I disable the root account) from /etc/ssh/sshd_config by making sure that the relevant line reads PermitRootLogin no and then restarting ssh
3. Installing some harden packages: sudo aptitude install harden-servers harden-clients harden-tools
4. Installing some helpful security packages: sudo aptitude install debsums logcheck denyhosts chkrootkit and then doing a dpkg-reconfigure on debsums to make sure it does a daily integrity check and altering the denyhosts config file to make it sync with the global denyhosts database (this helped cut down on automated ssh attacks tremendously)
5. One of the most important things to do is also to make sure that you get your local mail delivered so that you can see status reports. I do a sudo dpkg-reconfigure exim4-config to make certain everything is as I like it and that no holes are left open but I still get my system mail.
6. The last thing that I’ll do is to install nmap and scan myself to see what’s showing. For this particular box, I saw nothing but SSH and SMTP from the box itself and nothing but SSH from the outside. Good.

There might be a few other things which I do but I can’t recall them now. I would install SELinux but my understanding (according to the Debian Wiki) is that it’s still in the experimental stage so I won’t move on that just yet. Is there something huge and obvious that I’m forgetting security wise? Is a file-integrity checker going to be useful if I have constantly-changing and files and I am continually-updating packages?

The other major change is that I moved from the XFS filesystem back to ext3 with the intention of soon trying the upgrade-in-place features found in ext4 now that it’s got so many things which I liked about XFS. Since the Debian installer didn’t present me with an option to use ext4, this seemed like the best idea. Was I very wrong?

As a side note, I tried out weechat on the console for about an hour before immediately going back to ERC on Emacs because it integrates so well with my alltime favorite editor.

Saw this article (hat tip to Mukidohime)which pointed me to this email telling me that the kernel firmware resolution was finally voted on and Debian Lenny is now free to be released! It’s a good thing and I’m very excited for the goodies which will show up in Squeeze, set to be the new testing. Also saw this article on Ars Technica and this post on OStatic.

I looked around and found a wonderful tool called apt-proxy which will act as both intelligent cache and partial mirror for machines on a network. You set up apt-proxy on one machine with the names of whatever package repositories you want to use along with a few other settings.  I got some pointers from a wonderful article at Debian Administration by Steve when I was messing with the default config provided with the package. Once that’s all set up, you change all of the other machines’ sources.list point to the apt-proxy mirror you just set up. Then machines requests will get intelligently filtered through apt-proxy and duplicate packages will be cached for multiple machines. It’s great because it makes subsequent updates faster and simplifies mirror management on different machines. I could see this being very handy for clusters and doing large installs.