Use CDN domains in `releases-index.json`

[richlander]

We are using direct blob storage links in our JSON files. That is bad for performance and for infra flexibility. We should consider changing to a CDN.

core/release-notes/releases-index.json

Lines 15 to 16 in 218ef74

	"releases.json": "https://dotnetcli.blob.core.windows.net/dotnet/release-metadata/9.0/releases.json",
	"supported-os.json": "https://dotnetcli.blob.core.windows.net/dotnet/release-metadata/9.0/supported-os.json"

[Varorbc]

I'm wondering if release-index can be set up to use a CDN, since it relies on GitHub links through the Azure Pipeline task, which is causing a lot of trouble for users trying to access it from China.

[richlander]

It's already on a CDN, but don't take a dependency on the following link.

https://dotnetcli.azureedge.net/dotnet/release-metadata/releases-index.json

Note: We are in the middle of changing our CDN per https://learn.microsoft.com/azure/frontdoor/migrate-cdn-to-front-door.

We're going to publishing new guidance (hopefully) starting Monday.

[Varorbc]

could you take a look at this pull request and give me some advice? Also, which URL should I be using?

[richlander]

We are talking with the pipelines team in the morning (Pacific time). I already shared this issue with them. We will discuss it.

[Varorbc]

This is awesome news! This issue has been bothering Chinese users for so long. Really appreciate it, thank you so much! Sorry to bother you.

[richlander]

No bother.

Our new CDN is working (as of 10mins ago).

https://builds.dotnet.microsoft.com/dotnet/release-metadata/releases-index.json

[richlander]

This issue has been bothering Chinese users for so long.

Is there a blog post that describes this in more detail? I want to understand better.

[Varorbc]

Ah, I see the links in the pipeline are from GitHub. Due to the GFW (Great Firewall) in China, many sites, including GitHub, can't be accessed properly.

[richlander]

Sorry ... I get it now. You are proposing that Azure DevOps (at least for this scenario) should have no dependence on GitHub.

I was getting mixed up between Actions and Azure DevOps. I have been talking to both teams over the last couple days. We need to move both teams to our new CDN.

We'll be publishing new information about the CDN, shortly.

[mmitche]

Primarily there are two changes here:

• We should use the new vanity URLs when generating the releases index.json
• Consumers should pull the releases index from the CDN

[mmitche]

We should, however, verify that use of the vanity URIs (backed by Akamai or AFD CDNs) in the releases index does not adversely affect folks in China.