Azure APIM Global Load Balancing + Zone Redundancy with FrontDoor and Application Gateway

Question

My APIM is inside vnet with 3 locations enabled (multi-region with 1 unit in each region).
Architecture is : Front Door----App Gateway----APIM
As a front door backend, I created 3 backends, i.e 3 separate instances of App gateway (for each region) pointing to 3 instances of APIM in each region (MS docs suggest a way to get these 3 urls for each region, as they are not shown in Azure Portal). Total apim units are 3. And this architecture should provide me global multi region load balancing without any issues.

Scenario 1 :
Now I want to enable Zone redundancy for api gateway component only, so desired configuration will be 2 units of apim in 2 availability zones in each region. Total apim units will become 6 globally.
My question is, will apim internally load balance the request within availability zones of a region, I doubt it.. So, I assume that I need to add another backend in app gateway of a region. This app gateway was earlier pointing to only 1 unit instance of apim for that region. After enabling zone redundancy, I need to map the 2nd unit private ip as a backend in app gateway ?
With this simple 2nd backend addition for each of the 3 app gateway, I can achieve zone redundancy within each region. Please suggest if there is any issue.
-------But, Where can I see the private ip for the 2nd unit of apim instance ?

Scenario 2
Suppose, I want to enable multi-region or zone redundancy for the APIM Management Plane and Developer Portal in the Secondary Regions.
MS docs talks about enabling zone redundancy for management plane and developer portal only in Primary Region.
Is there a way to enable this in secondary regions?

Please guide

Answer 1

Hi @Amit-J Thanks for reaching out. for Scenario 1: You will have only one private ip for a region even if you enable zone redundancy, APIM will internally load balance the request within the availability zones of a region.

Scenario 2: APIM multi-region deployment only deploy gateway endpoint to secondary region regardless if the APIM service is deployed in VNET or not. Management, developer portal endpoints are only deployed in primary region.

Management, developer portal endpoints will not be available in secondary region and thus cannot be enabled and this is by design.

https://learn.microsoft.com/en-us/azure/api-management/api-management-howto-deploy-multi-region#about-multi-region-deployment

let me know incase of further queries, I would be happy to assist you.

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