I have already covered some tutorials where we deployed applications in Google app Engine. One of the main features associated with Google App Engine is that your application will never have any issues with regard to the scalability. This means that if the demand grows Google will automatically ‘copy’ your application to multiple servers to meet the requirements of the growing traffic.

Let’s take a simple case. Assume that you have developed an application that converts an image to ASCII characters. Typically the application in will residing in a particular server in the ‘Google cloud’ – say, in London. Over a period time, you application may lure more visitors and if your visitors are primarily from UK and US, then Google will copy your application to their server in US so that they can handle the traffic demands from US.

More over you get 500 MB free space for hosting these applications. This allows you to do experiments with the code. It will be even more useful if you could use a subdomain of your domain as the URL of your application (instead of appspot.com URL). This edition of techblog shows you how to do this.

Configuring your application

Go to the dashboard of your application and click on ‘Application Settings’ in the sidebar. This allows you to setup domain for that application. Click on the ‘Add Domain’ button and enter your domain name.

This will allow you to add the application to your Google apps account (provided you are already using this service). Go to ‘application settings’ in your Google Apps dashboard and select the name of the application which you just added.

Now click on the ‘Add new URL’ link.

Enter the name of the sub domain that you want to use and click ‘Add’.

Domain Configuration

This can be done using the interface provided by your webhost. An important point that you need to note here is that only few of the web hosting companies support this feature.

In order to perform the rest of the configuration, go to the CPanel (or any other control panel) account and locate the ‘Domains’ section. Now, select ‘Simple DNS Zone Editor’.

It is assumed that you have already created a sub domain which you want to use for the Google App Engine service.

Now go to the Simple Zone Editor and select your domain (if you are hosting multiple domains in the same account):

Locate the place where you can ‘add CName Record’. Enter the CNAME value (your sub domain name) and CNAME destination (which is ghs.google.com). Also, note that only few webhosts offer this feature (You can use this feature if you using Nazdrovia CPanel)

If you have WHM access, then you can easily add the CNAME using the DNS Zone editor tool.

Now you can access the application ,that you hosted in Google , using your own URL.

Also, you can see that the domain is actually pulling the data from Google servers (try pinging!)

php-app.aasisvinayak.com (74.125.43.121)

1     64 bytes from bw-in-f121.1e100.net (74.125.43.121): icmp_seq=1 ttl=245 time=61.1 ms
2     64 bytes from bw-in-f121.1e100.net (74.125.43.121): icmp_seq=2 ttl=245 time=60.9 ms
3     64 bytes from bw-in-f121.1e100.net (74.125.43.121): icmp_seq=3 ttl=245 time=61.1 ms
4     64 bytes from bw-in-f121.1e100.net (74.125.43.121): icmp_seq=4 ttl=245 time=61.4 ms
5     64 bytes from bw-in-f121.1e100.net (74.125.43.121): icmp_seq=5 ttl=245 time=61.2 ms
6     64 bytes from bw-in-f121.1e100.net (74.125.43.121): icmp_seq=6 ttl=245 time=61.0 ms
7     64 bytes from bw-in-f121.1e100.net (74.125.43.121): icmp_seq=7 ttl=245 time=61.3 ms
8     64 bytes from bw-in-f121.1e100.net (74.125.43.121): icmp_seq=8 ttl=245 time=61.2 ms

You may do ‘traceroute’  to see the route as well:

74.125.47.121 is from United States(US) in region North America

TraceRoute to 74.125.47.121 [php-app.aasisvinayak.com]

Hop    (ms)    (ms)    (ms)        IP Address    Host name

4    56    74    105        4.69.134.22    ae-7-7.ebr3.atlanta2.level3.net
5    200    39    259        4.68.103.2    ae-11-51.car1.atlanta1.level3.net
6    37    29    34        4.71.20.22    google-inc.car1.atlanta1.level3.net
7    92    56    36        209.85.254.243    –
8    42    46    69        209.85.253.169    –
9    32    31    33        74.125.47.121    yw-in-f121.1e100.net