openfoo blog

XenStore Dump of Rackspace Cloud

soeren — Fri, 23 Apr 2010 19:37:47 GMT

For the curious: A dump of the XenStore config for a VM running on RackSpace Cloud. Actually quite a straight forward and simple setup: using image files for both root and swap disks, and a bridged network setup for the two interfaces (one for internal, one for external). Although the network is bridged, the VM is not able obtain traffic for other VMs as they are using VLANs for separation.

Notes on Amazon EC2's Network

soeren — Thu, 22 Apr 2010 19:56:19 GMT

Shortly after publishing my notes on the EC2 architecture, I was looking into the networking setup of EC2 and in particular figuring out their address schemes. Since I am currently no longer interested in such information, I will publish my incomplete notes and the raw data gathered from about 80 instances in this post. My notes are based on information obtained from small instances in the us-east-1d zone.

Another Short Wish List for Amazon Web Services

soeren — Thu, 08 Apr 2010 16:19:10 GMT

In continuation of my first wish list, I will present another set of potential improvements and ideas for Amazon Web Services in this post. The focus lies on security groups and virtual private cloud.

How Do You Use Amazon's Security Groups?

soeren — Thu, 25 Feb 2010 21:06:07 GMT

This time I would like to reverse the flow of information and would kindly ask you to fill out the following questionnaire about how you use the Security Groups of Amazon Web Services. It will only take a few minutes of your time.

My Short Wish List for Amazon Web Services

soeren — Tue, 23 Feb 2010 21:40:08 GMT

In the short time I have used AWS, I came across a few issues which I would like to see changed by Amazon in the foreseeable future. It mainly concerns the management side of AWS rather than the technical one.

Amazon VPC with Linux

soeren — Tue, 23 Feb 2010 19:48:07 GMT

This post will cover how to connect a Amazon Virtual Private Cloud (VPC) with a Linux-based VPN gateway. In Amazon’s Network Guide for setting up a gateway connecting a VPC with existing infrastructure, they only provide specific configurations for Juniper and Cisco devices. Other devices, like a Linux-based VPN gateway, are covered by their documentation for Generic Devices, but lack specific configuration files. In this post I will explain how to setup a VPN gateway using racoon, ipsec-tools, and quagga on Ubuntu Linux.

AWS EC2 Java Library with Mock Objects

soeren — Thu, 18 Feb 2010 19:50:35 GMT

(Re-published as a separate post)

AWS EC2 SSH Config

soeren — Thu, 18 Feb 2010 19:50:35 GMT

In case you are connecting to various EC2 instances frequently for testing purposes, the following SSH config might be useful for you:

Jitter 2010-02-04

soeren — Thu, 04 Feb 2010 12:53:05 GMT

12:53: If you have enjoyed my post about EC2’s architecture, have a look on Guy Rosen’s latest post, where he digged deeper into the resource IDs and confirmed some interesting theories.

On Amazon EC2's Underlying Architecture

soeren — Mon, 01 Feb 2010 21:12:26 GMT

..or “Amazon EC2 Demystified”, but that sounded way too cheesy.

Review: Vibram Five Fingers KSO Trek Tex

soeren — Sun, 10 Jan 2010 16:58:33 GMT

This time a non-technical blog post, although it is about footwear hacking. Vibram released an innovative and clever product with their Five Fingers, which is getting increasingly popular. Baffled looks and curious questions guaranteed.

26C3

soeren — Thu, 31 Dec 2009 21:53:17 GMT

The 26C3 was a unique event as usual bringing together a wide variety of interesting people. It is a good opportunity to meet people in person, who you have not seen through out the year. The Congress is getting more popular each year – this year it was sold out after the first day – and it is getting very crowded with long queues before the lecture halls. This is definitely a drawback, but I can understand that it is difficult to find a new location for such a huge organizational event. However, I have to say that the organization improved compared to last year and it felt actually less crowded than last year.

Jitter 2009-12-31

soeren — Thu, 31 Dec 2009 19:04:22 GMT

00:13: Back from 26C3. Will post some comments about it tomorrow.

Website Deployment with Git

soeren — Wed, 30 Dec 2009 17:07:30 GMT

Besides keeping my blog in a version control system, I also want to keep my website in a repository. For this use case a distributed VCS is a good choice, because we can keep a repository on the workstation and one on the server, and push updates to the server. I choose git for this use case and this website provides an easy way to achieve pushing updates to the server and deploying the version controlled website using a post-receive hook script. It worked flawlessly for me and a minor adjustment of the hook script would be to fix the permissions of the deployed files, so they are only readable by the webserver.

Jitter 2009-12-27

soeren — Sun, 27 Dec 2009 08:51:03 GMT

08:51: Off to Berlin for 26C3!

Salmari Blog Software

soeren — Tue, 22 Dec 2009 16:13:45 GMT

This blog is generated using a Python script from text files residing in a subversion repository. I have uploaded the script (called Salmari) on github and will give some comments on the software in this post.

About OpenSolaris Security Updates

soeren — Sat, 12 Dec 2009 20:27:12 GMT

I am considering setting up an OpenSolaris 2009.06 server (since Hetzner now provides an OpenSolaris rescue system) for providing iSCSI ZFS volumes via VPN and hosting Xen domUs, but the fact that a stable OpenSolaris installation does not obtain security updates without a Sun support contract is a real show stopper. The basic support contract runs at 324 USD per year, which is quite out of the league for a personal used server. A discussion about this topic can be found here.

Emacs' auto-mode-alist

soeren — Wed, 09 Dec 2009 21:30:04 GMT

I discovered an interesting feature in emacs recently: For editing my blog posts in emacs I require certain modes enabled (e.g. longlines-mode), but these modes should not be enabled for regular text files. Basically the modes should be enabled for the text files in my blog directory.

Using Github's gist via Python

soeren — Tue, 08 Dec 2009 21:33:57 GMT

I was playing around with github’s gist, especially uploading snippets via python, so I can use it automated in my blog software. The result is the following python script:

Soft Linebreak Hell

soeren — Mon, 07 Dec 2009 21:26:50 GMT

I prefer writing my blog posts in a proper editor rather than in some web-based form in a browser. My blog software converts my posts written in textile to html, but it will also convert the hard linebreaks introduced by my editor (vim with tw=80) into html linebreaks, which is annoying.

HGMC: Haskell GMail Count

soeren — Sun, 06 Dec 2009 20:50:10 GMT

I am using XMonad in combination with xmobar and I wanted to display the current mail count for my gmail account. I wrote the following little Haskell tool to implement this behaviour using curl to retrieve the mail feed from google and do parsing with XML.Light and feed.

Hello World

soeren — Sun, 06 Dec 2009 14:43:01 GMT

I finally created an acceptable design for this new blog, so the first public entry could be made. The blog is powered by a textile to html converter written in Python, but I will probably post some notes about the blog software itself in the future. This blog will also host posts in a twitter-like form I call ‘jitters’ (which are posted via Jabber), but I have to experiment with them and conclude if they are useful at all.