To implement a load balanced learnexa environment, we had a look at the following areas -

What is the current cost of the solution and how does it compare with other offerings in the marketplace?
What are the options available for implementing a load balanced / fault tolerant solution?
What is the best possible solution?
Estimated Cost of implementing the solution

Comparing the cost of the current setup at different Service providers

Sources -
https://www.hpcloud.com/pricing
http://aws.amazon.com/ec2/#pricing
http://www.opsource.net/Services/Cloud-Hosting/Pricing
http://www.rackspace.com/cloud/servers/pricing/

What are the options available for implementing a solution?
(1) Using a hardware loadbalancer like Cisco ASA
(2) Load balancer provided by service provider
AWS or Opsource provides a hardware load balancer or through their marketplace offers software load balancers. The typical costs are at around USD 100 /month with some variable costs which are hard to estimate now.
(3) Configuring our own

Optimal Solution

At a high level
(1) We provide a host name for the customer to add in his DNS.
(2) currently we are redirecting *.learnexa.com to a specific IP address.
(3) we will follow the instructions as per the link given

  http://www.opsource.net/video/Part-4-of-8-Cloud-Load-Balancing-Building-a-Multi-tier-Cloud-Application\\

Immediate implementation steps at Opsource
(1) Build another app server Prodapp02
(2) Start the virtual IP configuration by going to Network configuration → VIP

  https://community.opsourcecloud.net/View.jsp?procId=31d3aef896d6e01e4cc8ac174fdc01c4

(3) Click on the physical servers tab and Prodapp01 and Prodapp02.
(4) Configure the probes which will keep checking the servers every (options with screenshots will be added shortly).
(5) Configure a server farm with options as per screenshot.
(6) Configure the virtual IP with the target as the server farm containing two physical servers prodapp01 and prodapp02.
(7) Save and test the configuration.
(8) Create customerxx.learnexa.com name in learnexa.com
*.learnexa.com
customerxx.learnexa.com
customeryy.learnexa.com
will point to the same single ip of the load balancer in Opsource.
Some sample suggestions -
http://stackoverflow.com/questions/975877/how-to-give-cname-forward-support-to-saas-software
http://stackoverflow.com/questions/2622740/how-to-handle-session-domains-in-a-cname-forward-supporting-rails-saas-software
http://httpd.apache.org/docs/2.2/vhosts/mass.html

(9)Apache configuration
<customerxx.learnexa.com>
will serve folder 1

<customeryy.learnexa.com>
will serve folder 2

Currently based on IP based virtual hosts are serving specific folders.
The new setup based on cname approach will use Name based virtual hosting and serve contents from their own folders.

(10) both the servers prodapp01 and prodapp02 will have the same folders / content and structure.
customerxx.learnexa.com
customeryy.learnexa.com
will both be available in these servers.

Confirmed from Opsource that this is part of the growth package and it is a hardware load balancer.

Estimated Cost for implementing the solution

* HPCloud - Load balancer is a software load balancer. No pricing information is available.

To be added–

(1) Estimated Timeline to implement the above Solution
Building up another app server and setting up the deployment and maintenance processes - duration for that needs to be verified from Uday.
As soon as the second app server is ready, the load balanced configuration can be implemented.