Testing managed identities in a local environment is not straightforward because managed identities are primarily designed for use within Azure resources. However, there are ways to simulate or emulate managed identities locally:
1. Enrolling in Azure Arc: You can enroll your local machine in Azure Arc, which allows you to assign a managed identity to your machine. This can be either a system-assigned or user-assigned managed identity. Once enrolled, you can test managed identities locally by assigning necessary permissions to the managed identity[1].
2. Emulating Managed Identity Locally: Another approach is to emulate the Azure managed identity service locally by running a mock instance metadata service. This involves simulating the token API to return an access token, typically using Azure CLI credentials. This method allows you to test code that uses managed identities without actually having them on your local machine[3].
3. Using DefaultAzureCredential: For most development scenarios, using `DefaultAzureCredential` is recommended. This credential automatically tries various authentication methods, including Visual Studio, Azure CLI, and Azure AD Integrated Authentication, to authenticate your application locally. While not using managed identities directly, it provides a similar seamless authentication experience[5][7].
In summary, while managed identities themselves cannot be used directly in a local environment, you can either emulate them or use alternative authentication methods like `DefaultAzureCredential` for local development.
Citations:
[1] https://www.foxdeploy.com/blog/how-to-migrate-an-azure-function-app-to-use-a-managed-identity.html
[2] https://stackoverflow.com/questions/67845857/can-a-user-assigned-managed-identity-be-used-locally
[3] https://gist.github.com/maskati/e0d74330dcf15848b043825cf6b2f8b7
[4] https://learn.microsoft.com/en-us/entra/identity/managed-identities-azure-resources/overview-for-developers
[5] https://www.reddit.com/r/AZURE/comments/1cilud6/managed_identities_and_local_developer_experience/
[6] https://learn.microsoft.com/en-us/entra/identity/managed-identities-azure-resources/how-manage-user-assigned-managed-identities
[7] https://stackoverflow.com/questions/75930046/how-to-run-azure-function-locally-using-user-assigned-managed-identity-configura
[8] https://www.codemag.com/Article/2107041/Eliminate-Secrets-from-Your-Applications-with-Azure-Managed-Identity
[9] https://learn.microsoft.com/en-us/azure/app-service/overview-managed-identity