There are different ways to back up VMs from different tenants/subscriptions in Veeam Backup for Microsoft Azure.
Multiple Microsoft Azure accounts may be added to Veeam Backup for Microsoft Azure. To handle VMs belonging to different accounts, add them as Azure accounts in Veeam Backup for Microsoft Azure. Then, a policy can be created for each account to process its VMs.
You can also use Azure Lighthouse as an option for Service Providers. Azure Lighthouse allows service providers to manage the resources of their customers.
When adding an Azure account, you can select the Azure Active Directory Group to which you can add a security AD application and contains customer resources that you can back up using Azure Lighthouse.
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