Posts

Showing posts from May, 2010

Setting up a mail server in EC2 with postfix and Postini

Setting up a mail server in 'the cloud' is notoriously difficult, mainly because many cloud-based IP addresses are already blacklisted, and also because you don't have control over reverse DNS in many cases. One way to mitigate these factors is to use Postini for outbound email from your cloud-based mail server. I've experimented with this in a test environment, with fairly good results. Here are some notes I jotted down. I am indebted to Jeff Roberts for his help with the postfix setup.

Let's assume you have a domain called mydomain.com and you want to set up a mail server in EC2 (could be any cloud provider) so that you can both send and receive email. I will also assume that you'll use Postini -- which currently costs $11/year/user. In my setup, I am mostly interested in sending mail out and less in receiving mail, so I only have one user: info@mydomain.com.

EC2 setup

I deployed a c1.medium EC2 instance running Ubuntu 9.04 and I also gave it an Elastic IP. Th…

Deploying MongoDB with master-slave replication

This is a quick post so I don't forget how I set up replication between a MongoDB master server running at a data center and a MongoDB slave running in EC2. I won't go into how to use MongoDB (I'll have another one or more posts about that), I'll just talk about installing and setting up MongoDB with replication.

Setting up the master server

My master server runs Ubuntu 9.10 64-bit, but similar instructions apply to other flavors of Linux.

1) Download MongoDB binary tarball from the mongodb.org downloads page (the current production version is 1.4.2). The 64-bit version is recommended. Since MongoDB uses memory-mapped files, if you use the 32-bit version your database files will have a 2 GB size limit. So get the 64-bit version.

2) Unpack the tar.gz somewhere on your file system. I unpacked it in /usr/local on the master server and created a mongodb symlink:

# cd /usr/local
# tar xvfz mongodb-linux-x86_64-1.4.1.tar.gz
# ln -s mongodb-linux-x86_64-1.4.1 mongodb

3) Create a mong…

Python Testing Tools Taxonomy on bitbucket

Michael Foord (aka Fuzzyman aka @voidspace) has kindly jumpstarted the task of porting the Python Testing Tools Taxonomy (aka PTTT) to reStructuredText, and to put it up on bitbucket for easier collaboration. The new bitbucket project is called taxonomy. Michael ported the unit testing section so far.

Porting the original trac format to reST is not the most fun way to spend one's time, so we need collaborators. If you're interested in contributing to this project, please fork and let us know so we can commit your patches. Thanks!

RabbitMQ clustering in Ubuntu

I've been banging my head against various RabbitMQ-related walls in the last couple of days, so I wanted to quickly jot down how I got clustering to work on Ubuntu boxes, before I forget.

Scenario A
2 Ubuntu 9.04 64-bit servers (app01 and app02)1 Ubuntu 9.10 64-bit server (app03)all servers are part of an internal DNS zone My initial mistake here was to install the rabbitmq-server package via "apt-get install". On 9.04, I got version 1.5.4 or rabbitmq-server, while on 9.10 I got 1.6. As it turns out, the database versions (rabbitmq uses the Mnesia database) are incompatible in terms of clustering between these 2 versions.

When I tried to join the server running Ubuntu 9.10 to the cluster, it complained with:

error: {schema_integrity_check_failed,
           {aborted,{no_exists,rabbit_user,version}}}

So....I removed rabbitmq-server via "apt-get remove" on all 3 servers. I also removed /var/lib/rabbitmq (which contains the database directory mnesia) and /var/log/ra…

Getting wireless NIC to work on Thinkpad T410s with Ubuntu Lucid

I tweeted this before, but a blog post is less ephemeral and serves better as a longer-term memory for myself and maybe for others.

The Thinkpad T410s uses the Realtek rtl8192se wireless chip which doesn't play well with Ubuntu Lucid, even with the general release from last week. To get it to work, I had to:


1) Download Linux driver for rtl8192se from this Realtek page.
2) Untar the package, run make and 'make install' as root.
3) Reboot.


Unfortunately, you'll need to do this every time you upgrade the kernel, unless support for this chipset gets better.