Question

I have deployed an application on Google App Engine and I want to link a Subdomian to that application.
I currently have a domain that is linked to a “live” site. from Google documentation I understand that i need to set up my domain with Google Apps:

To serve your app on a custom domain, the domain must be set up with Google Apps
(Source)

What exactly that mean?
I’ve looked in Google documentation and could get a clear idea…
Does that will effected my “live” site in some way?

just to clarify, http://www.mydomain.com – points a site that i own and i want sub.mydomain.com to point to my Google application.

Answer 1

You need to make a CNAME to forward to your app address.
Let’s say your app address is https://yourapp.appspot.com, and you want sub.mydomain.com to forward to it, just do like below:

Please read THIS first, follow the steps until step 5. You’ll need to type your mydomain.com in step 3, and type sub in step 5. After these, you’ll some steps on how to Chang CNAME record, just follow:

1. set your host name to sub
2. Type: CNAME
3. IP address/host name: ghs.google.com.
4. Priority status: (whatever just make it’s the number)

OK, and you’ll visit your app by http://sub.mydomain.com, different hosting providers have different time to set it valid. 🙂

BTW, it’ll not effect your “live” site in any way. As your main site use mydomain.com, and you just need sub.mydomain.com. What GAE said is that, if you want to set mydomain.com to your app, you need to set A type instead of CNAME type in your host. This domain hosting method includes more steps, you’ll see GAE’s doc that you found, and so it will effect your live site.