Azure Entra ID, formerly known as Azure Active Directory (Azure AD), offers robust identity management solutions that include managed identities and system identities. These features simplify identity management and enhance security for Azure resources. This article explores the concepts of managed identity and system identity, their differences, and common use case scenarios.
Managed Identity
Managed identities in Azure provide Azure services with an automatically managed identity in Azure AD. This identity can be used to authenticate to any service that supports Azure AD authentication, without the need for credentials to be stored in your code.
Types of Managed Identities
- System-Assigned Managed Identity:
- Automatic Creation and Deletion: A system-assigned managed identity is created and tied directly to an Azure resource, such as a virtual machine or an Azure function. When the resource is deleted, the identity is automatically deleted.
- Unique to Resource: Each resource has its own unique identity.
- User-Assigned Managed Identity:
- Independent Management: A user-assigned managed identity is created as a standalone Azure resource. It can be assigned to multiple Azure resources.
- Reusable: This identity can be used by multiple resources, and it exists independently of any particular resource lifecycle.
Benefits of Managed Identities
- No Credential Management: Managed identities eliminate the need to manage credentials in your application code.
- Enhanced Security: Reduces the risk of credential leaks by removing hardcoded secrets and credentials.
- Ease of Use: Simplifies the process of obtaining tokens for Azure resources.
Use Case Scenarios
- Accessing Azure Key Vault: Use a managed identity to securely access secrets, keys, and certificates stored in Azure Key Vault.
- Azure Storage Access: Securely connect to Azure Storage without embedding storage account keys in your application code.
- Resource Authentication: Authenticate Azure resources like Azure App Service or Azure Functions to other Azure services without managing credentials.
System Identity
System identity is a concept often used interchangeably with system-assigned managed identity. It specifically refers to the identities automatically created and managed by Azure for specific Azure resources.
Characteristics of System Identity
- Automatic Management: Created and managed by Azure for a specific resource.
- Lifecycle Tied to Resource: The identity is automatically deleted when the resource is deleted.
- Unique Identity: Each resource has a unique system-assigned identity.
Use Case Scenarios
- Virtual Machines: Use system-assigned managed identities to allow virtual machines to authenticate and access resources without storing credentials.
- Azure Functions: Enable Azure Functions to access other Azure resources securely.
Differences Between Managed Identity and System Identity
While managed identity and system identity are related, they have distinct characteristics and use cases.
Key Differences
- Creation and Lifecycle:
- Managed Identity: Refers to both system-assigned and user-assigned managed identities.
- System Identity: Specifically refers to system-assigned managed identities that are tied to the lifecycle of an Azure resource.
- Assignment:
- System-Assigned Managed Identity: Automatically created for a specific resource and cannot be shared with other resources.
- User-Assigned Managed Identity: Created as a standalone resource and can be assigned to multiple resources.
- Use Cases:
- System-Assigned Managed Identity: Best for scenarios where a single Azure resource requires a unique identity, such as a virtual machine needing access to an Azure Key Vault.
- User-Assigned Managed Identity: Ideal for scenarios where multiple resources need to share the same identity, such as a group of VMs accessing a shared storage account.
Conclusion
Managed identities and system identities in Azure Entra ID provide a secure and efficient way to manage authentication and access to Azure resources. By understanding the differences and appropriate use cases for system-assigned and user-assigned managed identities, organizations can enhance security, reduce the risk of credential exposure, and streamline the management of Azure resources. Whether you’re securing access to Azure Key Vault, connecting to Azure Storage, or enabling resource authentication, managed identities offer a powerful solution to simplify and secure your Azure environment.
