Difference between workload managed identity, Pod Managed Identity and AKS Managed Identity

Azure Kubernetes Service(AKS) offers several options for managing identities within Kubernetes clusters, including AKS Managed Identity, Pod Managed Identity, and Workload Managed Identity. Here’s a comparison of these three options:

Key Features	AKS Managed Identity	Pod Managed Identity	Workload Managed Identity
Overview	A built-in feature of AKS that allows you to assign an Azure AD identity to your entire cluster	Allows you to assign an Azure AD identity to an individual pod	Allows you to assign an Azure AD identity to a Kubernetes workload, which can represent one or more pods
Scope	Cluster-wide	Pod-specific	Workload-specific
Identity Type	Service Principal	Managed Service Identity	Managed Service Identity
Identity Location	Cluster	Node	Node
Usage	Generally used for cluster-wide permissions, such as managing Azure resources	Useful for individual pod permissions, such as accessing Azure Key Vault secrets	Useful for workload-specific permissions, such as accessing a database
Limitations	Limited to one identity per cluster	Limited to one identity per pod	None
Configuration Complexity	Requires configuration of AKS cluster and Azure AD	Requires configuration of individual pods and Azure AD	Requires configuration of Kubernetes workloads and Azure AD

Here are a few examples of how you might use each type of identity in AKS:

AKS Managed Identity

Suppose you have an AKS cluster that needs to access Azure resources, such as an Azure Key Vault or Azure Storage account. You can use AKS Managed Identity to assign an Azure AD identity to your entire cluster, and then grant that identity permissions to access the Azure resources. This way, you don’t need to manage individual service principals or access tokens for each pod.

Pod Managed Identity

Suppose you have a pod in your AKS cluster that needs to access a secret in Azure Key Vault. You can use Pod Managed Identity to assign an Azure AD identity to the pod, and then grant that identity permissions to access the secret in Azure Key Vault. This way, you don’t need to manage a separate service principal for the pod, and you can ensure that the pod only has access to the resources it needs.

Workload Managed Identity

Suppose you have a Kubernetes workload in your AKS cluster that needs to access a database hosted in Azure. You can use Workload Managed Identity to assign an Azure AD identity to the workload, and then grant that identity permissions to access the database. This way, you can ensure that the workload only has access to the database, and you don’t need to manage a separate service principal for each pod in the workload.

In summary, each type of AKS identity has its own strengths and use cases. AKS Managed Identity is useful for cluster-wide permissions, Pod Managed Identity is useful for individual pod permissions, and Workload Managed Identity is useful for workload-specific permissions. By choosing the right type of identity for your needs, you can simplify identity management and ensure that your AKS workloads have secure and controlled access to Azure resources.