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Interesting links from 25th February 2009

At home sick today so caught up on some very dry reading.  A lot of old links here but interesting none the less if you are in to designing scalable platforms for hosting web applications.

• Scalable Linux Clusters with LVS, Part I - http://tag1consulting.com/Scalable_Linux_Clusters_with_LVS_Part_I
  Intro to using LVS for load balancing.
  
• Design Patterns - http://c2.com/cgi/wiki?DesignPatterns
  Good reference for development documenting some handy "design patterns".
  
•  Network Design Patterns: N-Tier Data Centers - http://www.sun.com/blueprints/1003/817-3997.pdf
  A pdf from sun written a few years back talking about network design patterns for data centres.
  
• Network Naming Schemes - http://www.namingschemes.com/Main_Page
  For those stuck trying to think up an original naming scheme for their network.
  
• Domain Name Humor - http://www.domainhandbook.com/humor1.html
  Some light humour after all the dry material.
  
• RFC 1178 - Choosing a name for your computer - http://tools.ietf.org/html/rfc1178
  There is even an RFC to help you name your computer.
  
• Gravatar - Globally Recognized Avatars - http://www.gravatar.com/
  Why not add gravatars to your software?
  

How to Build an OpenQRM 4.3 Server

OpenQRM is an open source datacentre management tool that helps automate the build and management of hosts.  It integrates with other automation tools such as puppet and has a relativly simple plugin architecture. This HowTo describes how to get a clean installation up and running on a bare bones CentOS system.

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How to make a simple drop box with ProFTPd

First thing is to make a directory for the dropbox with the permissions of the user that is going to be the owner of the dropbox. You will also want to make the directory write only and sticky for the owner.

# mkdir /home/username/dropbox
# chown username:groupname /home/username/dropbox
# chmod 3333 /home/username/dropbox

Next thing to do is to create the user that people using the dropbox are going to use.

# adduser --home /home/user/dropbox --no-create-home fileuser

Then create an entry in your proFTPd conf file (usualy in /etc/proftpd.conf) like the following.

<directory /home/username/dropbox>
     AllowOverwrite off
     HiddenStor on
     Umask 007
</directory>

The last thing to do is set up a cron entry to clear the dropbox into an uploads folder to be checked by the owner at a later stage. Obviously it isn’t a good idea to make this folder publicly accessible unless you want to become a warez site.

# mkdir /home/user/uploads
# chmod go-rwx /home/username/uploads

Then add an entry to your crontab to run however often you want.

* * * * * /bin/mv /home/username/dropbox/* /home/username/uploads/

Obviously this doesn’t have any version control, and perhaps checking every minute is a little excessive but you should get the idea.

And that should be it. Reload your daemons and you should have a working drop box for clients to upload documents, proofs, designs or other documents and files.