Using user-assigned managed identities for applications with multiple resources offers several advantages:
1. Flexibility and Control: User-assigned managed identities are created independently and can be assigned to multiple Azure resources across different resource groups or subscriptions. This allows for greater control over the identity lifecycle, as it is not tied to the lifecycle of any specific resource[2][3][5].
2. Efficiency in Management: By using a single user-assigned identity across multiple resources, the administrative overhead is reduced. Fewer distinct identities and role assignments need to be managed, which simplifies the process of granting permissions and monitoring access[3][5].
3. Compliance and Approval Processes: In scenarios where identity creation requires approval, using a single user-assigned identity across multiple resources reduces the number of approvals needed compared to creating system-assigned identities for each resource[3].
4. Pre-Deployment Access: User-assigned identities can be configured in advance of resource creation, ensuring that resources have the necessary permissions as soon as they are deployed. This is particularly useful when resources require access to other Azure services during their deployment process[3].
5. Cost-Effectiveness: Like all managed identities, user-assigned identities incur no additional charges, making them a cost-effective solution for managing credentials across multiple resources[1].
6. Security Enhancements: User-assigned managed identities eliminate the need to embed credentials within application code, reducing the risk of credential leaks and enhancing overall security[2][5].
7. Role-Based Access Control (RBAC): User-assigned identities support RBAC, allowing administrators to assign specific permissions to the identity, ensuring that resources only have the necessary access to perform their tasks[2][5].
Citations:
[1] https://www.varonis.com/blog/azure-managed-identities
[2] https://www.linkedin.com/pulse/what-managed-identities-azure-resources-sardar-mudassar-ali-khan-
[3] https://learn.microsoft.com/en-us/entra/identity/managed-identities-azure-resources/managed-identity-best-practice-recommendations
[4] https://docs.azure.cn/en-us/entra/identity/managed-identities-azure-resources/managed-identities-faq
[5] https://www.techtarget.com/searchcloudcomputing/tip/Managed-identity-vs-service-principal-for-Azure-apps
[6] https://docs.azure.cn/en-us/azure-resource-manager/managed-applications/publish-managed-identity
[7] https://learn.microsoft.com/en-us/entra/identity/managed-identities-azure-resources/overview
[8] https://cloudtips.nl/the-magic-of-azure-managed-identities-%EF%B8%8F-19747c37e652