FOSS.IN 2010 list of talks announced

The final list is here http://foss.in/talks/final-list.html#more-1674

There are some very interesting talks, I am speaking on "Operating System Caches in a virtualized environment". Please do attend

Fedora 14 is out

Get Fedora 14 from https://fedoraproject.org/get-fedora. The website has a great new look and feel, check out http://fedoraproject.org/.

Checkout some of the cool tools and features at http://fedoraproject.org/en/features/

libcgroup has been updated to  0.36.2, I'd recommend moving to 0.37 (it should be available soon)

I've been using Fedora for a long time and constantly since Fedora 11. I still remember seeing Fedora core 1 announced and Fedora core 2 shipped with the 2.6 kernel, wow! we've really come a long way! There is much more to cover.

Arguing about OS'es

Gopal and I argued about Linux, Windows and browsing (nothing out of the ordinary though, we kill time in arguments and we've mastered that art). I thought I'd share what the stats look like for visitors on my blog. If you are worried about being profiled, don't worry, no personal information is stored by me! The data is from sitemeter and blogspot (If you are too concerned, you can start using the "Private browsing" or Incognito Windows)

Browser Share

Operating system share

Feeling insecure - thoughts on SELinux

I've decided to run Fedora on my main desktop and enable other distros via virtualization. Yes, too many good solutions to ignore and I paid for the hardware. Anyway, this is not an entry about virtualization, but on SELinux. Fedora enables SELinux by default and I was left to live with the consequences. To try and make sure I get the same five star security on my desktop that enterprise applications get, I decided not to add selinux=0 to the boot command prompt.

I thought I could learn it, wouldn't I be an inferior being if I could not? What does it say about my go-getter attitude? My first encounter with SELinux was when I tried to get ~user/public_html enabled via the Apache Web Server. After I had followed the documentation, I still could not get a seemingly easy feature to work. I dig the web and without knowing too much, I learn about a certain context httpd_user_context_t and use a certain tool and it worked!!!

I had a grin on my face for a few days, I was going to be able to work with SELinux. My next surprise came when I tried to install some software and setroubleshootd very gently pointed me to the cause of the security violation while installing the software and what I could do to fix it (gee, an automated tool, no more worries). My next encouter occurred when I tried to install mediawiki with math enabled (yeah.. I decided to save paper and take notes on the wiki with TeX enabled, but that is a different story). Again, no matter how well I followed the guidelines, I could not get texvc to work :(

Remember to look at /var/log/audit files as root and run audit2allow to get some useful hints with SELinux. SELinux comes with a set of rich GUI tools, be sure to use them as you walk through the seemingly friendly maze of SELinux

I found some help on the mediawiki site that gave me instructions on how to setup SELinux and mediawiki together. To my surprise, I found quite a few software vendors providing additional instructions for setup when SELinux is enabled.

The feeling of being miserable at SELinux set in, I had to now read up and understand the architecture or forgo my new found security infrastructure. Today, I came across a very interesting web page (the wikipedia entry for SELinux),

“...given the threat models and capabilities of the adversaries involved, that's probably appropriate... But that’s not necessarily appropriate for all users. SELINUX is so horrible to use, that after wasting a large amount of time enabling it and then watching all of my applications die a horrible death since they didn't have the appropriate hand-crafted security policy, caused me to swear off of it. For me, given my threat model and how much my time is worth, life is too short for SELinux.” — Theodore Ts’o

You can only imagine how relieved I was to see this quote

Life is too short for SELinux

I was not alone, others hated it and found it hard to use as well. How pathetic can such happiness be, but I was overjoyed, excited to say the least.

My path forward is to continue to use SELinux, but be less tolerant of its idiosyncrasies. I am working my way through the documentation, but very slowly. I've learnt that my new best friend is "Z". Add "Z" to existing commands in Fedora and magically it shows SELinux information that can be a life saviour at times.

Memory Ordering (Recommended Reading)

I just finished reading this wonderful report on memory ordering. I highly recommend reading it. If you have anything to do with multi-core, multi-processor, parallel programming, you'll find the paper very insightful.

Other good to read papers/articles on memory ordering from Paul Mckenney are

1. C++ Data-Dependency Ordering. May 2007.
2. Overview of Linux-Kernel Reference Counting. January 2007.
3. A simple and efficient memory model for weakly ordered architectures. Makes case for weakly ordered primitives in programming languages. Updated May 2007.

Kernel summit 2007 group photo

Posted at LWN.net

Kernel Summit Photos - taken by Evgeniy Polyakov

Peter Zijlstra, Ingo Molnar, Venki Pallipadi and Balbir Singh in discussion

More photos will follow, including the group photo. Meanwhile, there are other photos at Evgeniy Polyakov's gallery.

Off to Ottawa Linux Symposium

I am off to the Linux Symposium in Ottawa, I was supposed to travel to Linux Symposium Japan, but could not (unfortunately!)

You can catch me at the following events

1. Generic Process Containers
2. Where is your application stuck
3. Containers: Challenges with the memory controller
4. Resource Management BOFs