Is Microsoft Azure CDN A Real CDN Or Something Else Entirely?

Question

I've just tried setting up an Azure CDN account, and so far (going on four hours now) I haven't been able to get it to return anything except 400 and 404 errors.

If this were a real CDN all I would need to do is point the CDN at my website and make a request to the CDN for a file; for example http://myaccount.vo.msecnd.net/images/1.jpg or http://myaccount.blob.core.windows.net/images/1.jpg. The CDN would then either serve the file to the client out of its cache or it would make a request to my website (e.g. http://www.myaccount.com) for the file, store it in its cache, and then serve it to the client.

Well, this certainly doesn't seem to be the case. I've gone through all of the steps in the Azure Management Portal to create my Storage Account, my CDN Endpoint, and my Custom Domain, including the CNAME Verify step, which (apparently) worked because the portal shows my Custom Domain as allowed (and the CDN Endpoint as Enabled, and the Storage Account as Created, and the Subscription as Active).

So if Azure isn't really setting up a CDN, then what is it actually doing? Am I supposed to physically upload all of the content from my site to the Azure CDN? If that's the case, then what's the point of having a Custom Domain?

I'm hoping someone can either point out what I'm not understanding, or let me know if I'm wasting my time trying to use the Azure CDN as I would use a real CDN.

Answer 1

The CDN is what you expect it to be. Note that it may take (really) up to about an hour for DNS changes to propagate worldwide. The CDN either sits in front of a blob storage account or a web application (but not both simultaneously as it seems you might be intending).

Note that the custom domain and the CDN are separate, so you can test just against the raw CDN URL (*.vo.msecnd.net) to make sure everything's set up and later worry about the custom domain.

Is your CDN endpoint on top of blob storage? or a web app?

If you browse to the same URL directly from blob storage (*.blob.core.windows.net/path vs. *.vo.msecnd.net/path), does it work?

Answer 2

After reading the comment from smarx I contacted Microsoft Customer Support for clarification, and this is the answer I received.

To answer your question, “yes Windows Azure CDN” is real CDN and it uses 24 nodes
worldwide to deliver your content.

There is one basic difference then other CDN is that Windows Azure CDN sits
configuration is top of Windows Azure Storage, that means, you will create a
Cloud base Storage service in Windows Azure Storage and stop all of your data
there. Once you will configure your Azure Storage to act as CDN the same data
which is stored in your Windows Azure Storage service will be cached into
currently available 24 nodes worldwide.

I think the following difference may confused you:

While other CDN service, you can point CDN to read data from your own premise
servers, however in Windows Azure you will have to move your content from your
on-premise servers to Windows Azure Storage. As in Cloud Storage based CDN
Model, it is user responsibility to upload data to Azure Storage first and if
the Storage Service is configured as CDN, you will have the same CDN function-
ality as any other CDN.

Without the ability to point the Azure CDN at our own servers and fetch / cache static content I can't see how Microsoft hopes to compete with all of the other content delivery networks that offer pull-through and caching. The only assumption I can make is that the Azure CDN service is still a work in progress, and will someday be able to offer the same capabilities as other CDN services.