Custom Image and number of Pool recommended

Question

Hello,

I am building a Azure Batch application. This application is supposed to launch multiple pools using Shared Image Gallery images.

As per the link: https://learn.microsoft.com/en-us/azure/batch/batch-custom-images#considerations-for-large-pools , "We don't recommend using an image or its underlying snapshot for more than a single pool."

Can you please provide more details why multiple Pools with same custom image is not recommended?
Is this recommendation applicable for multiple Pools created using Shared Image Gallery?

Thanks in Advance!

Answer 1

@KaleVaibhav-3069 Apologies for the delay in response.

This consideration was primarily for the older managed images form of custom images. This was due to them essentially all reading from the same storage entity when getting set up which could cause failures on create.

Shared image galleries with an appropriate number of replicas should suffice.

This restriction is not applicable to Shared Image Gallery based Pools. You need to ensure that you have enough replicas setup in Shared Image Gallery for catering to peak load of VMs across multiple pools (only ~600 VMs can be served with 1 replica, so for a peak load of 3000 VMs across pool,you need to have 5-6 replicas in the SIG).

Hope this answer your queries.

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