I'm working on trying to pre-load our assets onto our CDN profile, but I'm having issues understanding/proving whether it's working or not. After following the instructions in the documentation, I waited about an hour before logging into a VPN to test, and found that my file wasn't cached (didn't have the appropriate response headers). So my first couple questions are: Does doing the pre-load process hit all the edge nodes? How long does that process actually take? Are there any settings in my blob storage that could prevent the files from being cached? I'm using the Azure.ResourceManager.Cdn package to do this in C#, and I have gotten a 200 response, but even after waiting hours, when I ping a file, it doesn't seem as if it is cached.

How exactly does the pre-load of assets on CDN endpoints work?

Kevin Hebert 1

I'm working on trying to pre-load our assets onto our CDN profile, but I'm having issues understanding/proving whether it's working or not. After following the instructions in the documentation, I waited about an hour before logging into a VPN to test, and found that my file wasn't cached (didn't have the appropriate response headers). So my first couple questions are:

Does doing the pre-load process hit all the edge nodes?
How long does that process actually take?
Are there any settings in my blob storage that could prevent the files from being cached?

I'm using the Azure.ResourceManager.Cdn package to do this in C#, and I have gotten a 200 response, but even after waiting hours, when I ping a file, it doesn't seem as if it is cached.

KapilAnanth-MSFT 35,001 Reputation points Microsoft Employee

2023-06-06T07:55:21.41+00:00

@Kevin Hebert

Welcome to the Microsoft Q&A Platform. Thank you for reaching out & I hope you are doing well.

I shall check this and get back to you soon.

Cheers,

Kapil
KapilAnanth-MSFT 35,001 Reputation points Microsoft Employee

2023-06-07T04:22:48.97+00:00
@Kevin Hebert

I got an update that With Azure CDN from Verizon, pre-load does hit all edge nodes and propagation item is around a couple of minutes.

May I ask how you are confirming if the file isn't cached?

When you specify "didn't have the appropriate response headers" - Can you elaborate please?

Cheers,

Kapil
Kevin Hebert 1 Reputation point

2023-06-07T14:28:49.23+00:00

@KapilAnanth-MSFT

I am using a VPN to connect to different servers located close to edge nodes. I then attempt to load my file, and look at the response headers. Particularly I'm looking for the "Age" and "X-Cache" headers, as well as a header value that isn't "Windows-Azure-Blob".
KapilAnanth-MSFT 35,001 Reputation points Microsoft Employee

2023-06-08T07:20:27.47+00:00
@Kevin Hebert

I wouldn't say this is a right approach.

What values are you seeing in "Age" and "X-Cache" headers ?

You must debug this using the Verizon-specific HTTP headers.

Make sure enable Debug Cache Response Headers feature, be sure to add the necessary X-EC-Debug headers.

Refer:

Debug Cache Response Headers

Debug Cache Response Headers Information

Thanks,

Kapil
Kevin Hebert 1 Reputation point

2023-06-08T14:14:48.5833333+00:00

@KapilAnanth-MSFT

That's the thing, I'm not seeing those headers at all upon my first visit. But I see them after the first visit when I refresh the file.

As for the specific headers you've linked, I'm not seeing any of those in the Response Headers either. The current headers I'm seeing are on my first visit after attempting a preload are:
Kevin Hebert 1 Reputation point

2023-06-08T14:20:23.2733333+00:00

Double post.
KapilAnanth-MSFT 35,001 Reputation points Microsoft Employee

2023-06-08T14:26:10.46+00:00

@Kevin Hebert

You must enable those headers in the Rule Engine of Verizon, and that's how you can troubleshoot caching.

Since this is a third party partnership offering, there are documents lacking from Azure.

To troubleshoot the exact issue, I would suggest we need a specialized 1:1 session, where a support engineer can get in touch with Verizon team. If you have a support plan you may file a support ticket, else please do let us know, we will try and help you get a one-time free technical support.

Thanks,

Kapil