Edit

Dapr

  • Article

Distributed Application Runtime (Dapr) offers APIs that help you write and implement simple, portable, resilient, and secured microservices. Dapr APIs run as a sidecar process in tandem with your applications and abstract away common complexities you may encounter when building distributed applications, such as:

  • Service discovery
  • Message broker integration
  • Encryption
  • Observability
  • Secret management

Dapr is incrementally adoptable. You can use any of the API building blocks as needed. Learn the support level Microsoft offers for each Dapr API and component.

Capabilities and features

Using the Dapr extension to provision Dapr on your AKS or Arc-enabled Kubernetes cluster eliminates the overhead of:

  • Downloading Dapr tooling
  • Manually installing and managing the Dapr runtime on your AKS cluster

You can install, deploy, and configure the Dapr extension on your cluster using either the Azure CLI or a Bicep template.

Additionally, the extension offers support for all native Dapr configuration capabilities through simple command-line arguments.

Dapr provides the following set of capabilities to help with your microservice development on AKS:

  • Easy provisioning of Dapr on AKS through cluster extensions.
  • Portability enabled through HTTP and gRPC APIs which abstract underlying technologies choices
  • Reliable, secure, and resilient service-to-service calls through HTTP and gRPC APIs
  • Publish and subscribe messaging made easy with support for CloudEvent filtering and “at-least-once” semantics for message delivery
  • Pluggable observability and monitoring through Open Telemetry API collector
  • Works independent of language, while also offering language specific software development kits (SDKs)
  • Integration with Visual Studio Code through the Dapr extension
  • More APIs for solving distributed application challenges

Currently supported

The Dapr extension is the only Microsoft-supported option for Dapr in AKS.

Issue handling

Microsoft categorizes issues raised against the Dapr extension into two parts:

  • Extension operations
  • Dapr runtime (including APIs and components)

The following table breaks down support priority levels for each of these categories.

Description Security risks/Regressions Functional issues
Extension operations Issues encountered during extension operations, such as installing/uninstalling or upgrading the Dapr extension. Microsoft prioritizes for immediate resolution. Microsoft investigates and addresses as needed.
Dapr runtime Issues encountered when using the Dapr runtime, APIs, and components via the extension. Microsoft works with the open source community to investigate high priority issues. Depending on priority, severity, and size of the issue, Microsoft either resolves them directly in the extension, or works with the Dapr open source project to resolve in a hotfix or future Dapr open source release. Once fixes are released in Dapr open source, they are then made available in the Dapr extension. Microsoft investigates new functional issues alongside the Dapr open source project and collaborates with them to resolve in a hotfix or future Dapr open source release. Known open source functional issues won't be investigated by Microsoft at this time.

Dapr versions

Microsoft provides best-effort support for the latest version of Dapr and two previous versions (N-2). The latest patch version is the only supported version of each minor version release. Currently, the Dapr extension for AKS or Arc-enabled Kubernetes supports the following Dapr versions:

  • 1.13.x
  • 1.12.x
  • 1.11.x

The Dapr extension support varies depending on how you manage the runtime.

Self-managed

Self-managed runtime requires manual upgrade to remain in the support window. To upgrade Dapr via the extension, follow the Update extension instance instructions.

After a Dapr runtime version reaches end of Microsoft support, your applications continue to run unchanged. However, Microsoft can no longer provide security patches or related customer support for that runtime version. If your application encounters any problems past the end-of-support date for that version, we recommend upgrading to a supported version to receive the latest security patches and features.

Auto-upgrade

Enabling auto-upgrade requires careful consideration. While auto-upgrade keeps your Dapr extension updated to the latest minor version, you may experience breaking changes between updates. Microsoft isn't responsible for any downtime caused due to breaking changes between auto-updates.

Components and APIs

You can use all Dapr components and APIs via the Dapr extension, including those in alpha and beta status. However, Microsoft only provides support to a subset of APIs and components, following the defined issue handling policies.

Stable Dapr APIs

The Dapr extension supports stable versions of Dapr APIs (building blocks).

Dapr API Status Description
Service-to-service invocation Stable Discover services and perform reliable, direct service-to-service calls with automatic mTLS authentication and encryption.(#limitations)
State management Stable Provides state management capabilities for transactions and CRUD operations.
Pub/sub Stable Allows publisher and subscriber apps to intercommunicate via an intermediary message broker. You can also create declarative subscriptions to a topic using an external component JSON file.
Bindings Stable Trigger your applications based on events.
Actors Stable Dapr actors are message-driven, single-threaded, units of work designed to quickly scale. For example, in burst-heavy workload situations.
Observability Stable Send tracing information to an Application Insights backend.
Secrets Stable Access secrets from your application code or reference secure values in your Dapr components.
Configuration Stable Retrieve and subscribe to application configuration items for supported configuration. stores.

Tier 1 versus Tier 2 components

A subset of Dapr components is supported for the Dapr extension for AKS and Arc-enabled Kubernetes. Within that subset, Dapr components are broken into two support categories: Tier 1 or Tier 2.

  • Tier 1 components: Stable components that receive immediate investigation in critical (security or serious regression) scenarios. Otherwise, Microsoft collaborates with open source to address in a hotfix or the next regular release.
  • Tier 2 components: Components that are investigated on a lesser priority, as they're not in stable state or are with a third party provider.
Tier 1 components
API Component Type
State management Azure Blob Storage v1
Azure Table Storage
Microsoft SQL Server		 state.azure.blobstorage
state.azure.tablestorage
state.sqlserver
Publish & subscribe Azure Service Bus Queues
Azure Service Bus Topics
Azure Event Hubs		 pubsub.azure.servicebus.queues
pubsub.azure.servicebus.topics
pubsub.azure.eventhubs
Binding Azure Storage Queues
Azure Service Bus Queues
Azure Blob Storage
Azure Event Hubs		 bindings.azure.storagequeues
bindings.azure.servicebusqueues
bindings.azure.blobstorage
bindings.azure.eventhubs
Tier 2 components
API Component Type
State management Azure Cosmos DB
PostgreSQL
MySQL & MariaDB
Redis		 state.azure.cosmosdb
state.postgresql
state.mysql
state.redis
Publish & subscribe Apache Kafka
Redis Streams		 pubsub.kafka
pubsub.redis
Binding Azure Event Grid
Azure Cosmos DB
Apache Kafka
PostgreSQL
Redis
Cron		 bindings.azure.eventgrid
bindings.azure.cosmosdb
bindings.kafka
bindings.postgresql
bindings.redis
bindings.cron
Configuration PostgreSQL
Redis		 bindings.postgresql
bindings.redis

Clouds/regions

Global Azure cloud is supported with AKS and Arc support on the following regions:

Region AKS support Arc for Kubernetes support
australiaeast ✔️ ✔️
australiasoutheast ✔️ ❌
brazilsouth ✔️ ❌
canadacentral ✔️ ✔️
canadaeast ✔️ ✔️
centralindia ✔️ ✔️
centralus ✔️ ✔️
eastasia ✔️ ✔️
eastus ✔️ ✔️
eastus2 ✔️ ✔️
eastus2euap ❌ ✔️
francecentral ✔️ ✔️
francesouth ✔️ ❌
germanywestcentral ✔️ ✔️
japaneast ✔️ ✔️
japanwest ✔️ ❌
koreacentral ✔️ ✔️
koreasouth ✔️ ❌
northcentralus ✔️ ✔️
northeurope ✔️ ✔️
norwayeast ✔️ ❌
southafricanorth ✔️ ❌
southcentralus ✔️ ✔️
southeastasia ✔️ ✔️
southindia ✔️ ❌
swedencentral ✔️ ✔️
switzerlandnorth ✔️ ✔️
uaenorth ✔️ ❌
uksouth ✔️ ✔️
ukwest ✔️ ❌
westcentralus ✔️ ✔️
westeurope ✔️ ✔️
westus ✔️ ✔️
westus2 ✔️ ✔️
westus3 ✔️ ✔️

Frequently asked questions

How do Dapr and Service meshes compare?

A: Where a service mesh is defined as a networking service mesh, Dapr isn't a service mesh. While Dapr and service meshes do offer some overlapping capabilities, a service mesh is focused on networking concerns, whereas Dapr is focused on providing building blocks that make it easier for developers to build applications as microservices. Dapr is developer-centric, while service meshes are infrastructure-centric.

Some common capabilities that Dapr shares with service meshes include:

  • Secure service-to-service communication with mTLS encryption
  • Service-to-service metric collection
  • Service-to-service distributed tracing
  • Resiliency through retries

In addition, Dapr provides other application-level building blocks for state management, pub/sub messaging, actors, and more. However, Dapr doesn't provide capabilities for traffic behavior such as routing or traffic splitting. If your solution would benefit from the traffic splitting a service mesh provides, consider using Open Service Mesh.

For more information on Dapr and service meshes, and how they can be used together, visit the Dapr documentation.

How does the Dapr secrets API compare to the Secrets Store CSI driver?

Both the Dapr secrets API and the managed Secrets Store CSI driver allow for the integration of secrets held in an external store, abstracting secret store technology from application code. The Secrets Store CSI driver mounts secrets held in Azure Key Vault as a CSI volume for consumption by an application. Dapr exposes secrets via a RESTful API that can be:

  • Called by application code
  • Configured with assorted secret stores

The following table lists the capabilities of each offering:

Dapr secrets API Secrets Store CSI driver
Supported secrets stores Local environment variables (for Development); Local file (for Development); Kubernetes Secrets; AWS Secrets Manager; Azure Key Vault secret store; Azure Key Vault with Managed Identities on Kubernetes; GCP Secret Manager; HashiCorp Vault Azure Key Vault secret store
Accessing secrets in application code Call the Dapr secrets API Access the mounted volume or sync mounted content as a Kubernetes secret and set an environment variable
Secret rotation New API calls obtain the updated secrets Polls for secrets and updates the mount at a configurable interval
Logging and metrics The Dapr sidecar generates logs, which can be configured with collectors such as Azure Monitor, emits metrics via Prometheus, and exposes an HTTP endpoint for health checks Emits driver and Azure Key Vault provider metrics via Prometheus

For more information on the secret management in Dapr, see the secrets management overview.

For more information on the Secrets Store CSI driver and Azure Key Vault provider, see the Secrets Store CSI driver overview.

How does the managed Dapr cluster extension compare to the open source Dapr offering?

The managed Dapr cluster extension is the easiest method to provision Dapr on an AKS cluster. With the extension, you're able to offload management of the Dapr runtime version by opting into automatic upgrades. Additionally, the extension installs Dapr with smart defaults (for example, provisioning the Dapr control plane in high availability mode).

When installing Dapr open source via helm or the Dapr CLI, developers and cluster maintainers are also responsible for runtime versions and configuration options.

Lastly, the Dapr extension is an extension of AKS, therefore you can expect the same support policy as other AKS features.

Learn more about migrating from Dapr open source to the Dapr extension for AKS.

How can I authenticate Dapr components with Microsoft Entra ID using managed identities?

How can I switch to using the Dapr extension if I’ve already installed Dapr via a method, such as Helm?

Recommended guidance is to completely uninstall Dapr from the AKS cluster and reinstall it via the cluster extension.

If you install Dapr through the AKS extension, our recommendation is to continue using the extension for future management of Dapr instead of the Dapr CLI. Combining the two tools can cause conflicts and result in undesired behavior.

Next Steps

After learning about Dapr and some of the challenges it solves, try Deploying an application with the Dapr cluster extension.