Feature Request: Azure Shared Image Gallery - Image definition created as part of builder

[ghost]

This issue was originally opened by @Marcus-James-Adams as hashicorp/packer#8803. It was migrated here as a result of the Packer plugin split. The original body of the issue is below.

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Following on from hashicorp/packer#7809

Packer should be self-contained and be able to do everything required within a builder without outside assistance.

currently, we have to do the following before running packer

Use az cli or PowerShell to create a shared image definition, e.g. for a customised Ubuntu 18.04-LTS image: az sig image-definition create --resource-group --gallery-name <my_shared_image_gallery> --gallery-image-definition --publisher --offer UbuntuServer --sku 18.04-LTS --os-type linux

It would be good if packer could create the definition automatically as part of the builder process.

[bhundven]

I also had to add the hyper-v generation, or you might get a generation mis-match:

az sig image-definition create --resource-group <resource_group_name> --gallery-name <my_shared_image_gallery> --gallery-image-definition <gallery_image_definition> --publisher OpenLogic --offer CentOS --sku 7_9-gen2 --os-type linux --hyper-v-generation V2