How to disable caching on specific origin with Azure Front Door load balancing?

Question

How to disable caching on specific origin with Azure Front Door load balancing?

Nibbler 656

Hello,

I have configured load balancing on Front Door Origin Group with two origins.

Origin 1 serves as the application, while the Origin 2 serves a maintenance page (simple index-html file) using a storage account (static web). Whenever Origin 1 is deemed unhealthy, requests are routed to Origin 2.

However, I don't want Origin 2 to be cached, so the maintenance page will not continue to be served when Origin 1 is healthy. How can I achieve this if possible?

Thanks.

Nibbler 656 Reputation points

2024-07-26T12:39:53.4866667+00:00

A note, I have tried creating a rule(s) overriding origin, and disabling caching, however, this also disables the caching for Origin 1 when its deemed healthy.

Mayby @GitaraniSharma-MSFT or @KapilAnanth could assist with a good approach on this?

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Nibbler 656 Reputation points

2024-07-26T12:39:53.4866667+00:00

A note, I have tried creating a rule(s) overriding origin, and disabling caching, however, this also disables the caching for Origin 1 when its deemed healthy.

Mayby @GitaraniSharma-MSFT or @KapilAnanth could assist with a good approach on this?

Answer 1

@Nibbler ,

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

Caching is done at Route and not at Origin Group or Origin.

So caching property cannot be configured for a specific Origin Group or Origin and this property would depend on the route only.

What you can instead do is use Cache-control directives at the "maintenance page" Origin.

In the AFD, you define the Cache behavior as either "Override if origin missing" or "Honor origin"
With "Override if origin missing"
- Don't specify any cache directives in the regular page, let AFD handle it
- In the maintenance page, specify the cache directives to not cache
With "Honor origin"
- In the regular page, specify the cache directives as appropriate
- In the maintenance page, don't cache
See :

Refer : Caching with Azure Front Door

Origins may specify not to cache specific responses using the Cache-Control header with a value of no-cache, private, or no-store. When used in an HTTP response from the origin server to the Azure Front Door POPs, Azure Front Door supports Cache-control directives and honors caching behaviors for Cache-Control directives in RFC 7234 - Hypertext Transfer Protocol (HTTP/1.1): Caching (ietf.org).

Hope this helps.

Thanks,

Kapil

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KapilAnanth 49,876 Reputation points Moderator

2024-07-31T06:30:34.1366667+00:00

@Nibbler ,

You can also leverage the AFD Access Logs

The field "Cache Status" should give you information whether or not the users were served by Cache or not

Thanks,

Kapil

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