Durable Task Scheduler

The Durable Task Scheduler is a fully managed Azure service purpose-built for running durable orchestrations. It provides the best experience for production workloads with zero infrastructure management and built-in enterprise support.

⭐ Recommended: For new projects, we recommend the Durable Task Scheduler as your backend provider.

Overview

Feature	Benefit
Fully Managed	No storage accounts, databases, or infrastructure to manage
Built-in Dashboard	Monitor orchestrations without additional tooling
Highest Throughput	Purpose-built for durable workflow performance
Azure Support	24/7 enterprise support with SLA (with Azure support plan)
Managed Identity	Secure authentication using Azure AD
Local Emulator	Docker-based emulator for development

For complete documentation on creating and configuring Azure resources, authentication, SKUs, RBAC, and pricing, see the official Azure documentation.

Installation

dotnet add package Microsoft.DurableTask.AzureManagedBackend

DTFx Code Sample

using DurableTask.Core;
using Microsoft.DurableTask.AzureManagedBackend;
using Microsoft.Extensions.Logging;

// Get connection string from environment
// Expected format: "Endpoint=https://<host>;Authentication=<credentialType>;TaskHub=<hubName>"
string? connectionString = Environment.GetEnvironmentVariable("DTS_CONNECTION_STRING");
if (string.IsNullOrWhiteSpace(connectionString))
{
    Console.Error.WriteLine("An environment variable named DTS_CONNECTION_STRING is required.");
    return;
}

// Configure logging
ILoggerFactory loggerFactory = LoggerFactory.Create(builder =>
    builder.AddSimpleConsole(options =>
    {
        options.SingleLine = true;
        options.UseUtcTimestamp = true;
        options.TimestampFormat = "yyyy-MM-ddTHH:mm:ss.fffZ ";
    }));

// Create the orchestration service for Durable Task Scheduler
AzureManagedOrchestrationService service = new(
    AzureManagedOrchestrationServiceOptions.FromConnectionString(connectionString),
    loggerFactory);

// Create and configure the worker
TaskHubWorker worker = new(service, loggerFactory);
worker.AddTaskOrchestrations(typeof(HelloWorldOrchestration));
worker.AddTaskActivities(typeof(HelloActivity));

// Start the worker
await worker.StartAsync();

// Create a client and start an orchestration
TaskHubClient client = new(service, null, loggerFactory);
OrchestrationInstance instance = await client.CreateOrchestrationInstanceAsync(
    orchestrationType: typeof(HelloWorldOrchestration),
    input: null);

Console.WriteLine($"Started orchestration with ID = '{instance.InstanceId}'");

// Wait for completion
OrchestrationState state = await client.WaitForOrchestrationAsync(
    instance, 
    TimeSpan.FromMinutes(1));

Console.WriteLine($"Orchestration completed with status: {state.OrchestrationStatus}");
Console.WriteLine($"Output: {state.Output}");

// Clean up
await worker.StopAsync();
service.Dispose();

Connection String Format

Endpoint=<scheduler-url>;TaskHub=<taskhub-name>;Authentication=<auth-type>

See Authentication Types for supported credential types.

Configuration Options

The AzureManagedOrchestrationServiceOptions class provides configuration for the Durable Task Scheduler backend.

Creating Options

From connection string (recommended):

var options = AzureManagedOrchestrationServiceOptions.FromConnectionString(connectionString);

Manual construction:

var options = new AzureManagedOrchestrationServiceOptions(
    address: "https://myscheduler.westus3.durabletask.io",
    credential: new DefaultAzureCredential());
options.TaskHubName = "my-task-hub";

Authentication Types

The connection string Authentication property supports these credential types:

Value	Credential Type	Use Case
DefaultAzure	DefaultAzureCredential	General purpose; tries multiple auth methods
ManagedIdentity	ManagedIdentityCredential	Azure-hosted apps; add ClientId for user-assigned
WorkloadIdentity	WorkloadIdentityCredential	Kubernetes, CI/CD pipelines, SPIFFE
Environment	EnvironmentCredential	Container apps with env var credentials
AzureCLI	AzureCliCredential	Local dev with az login
AzurePowerShell	AzurePowerShellCredential	Local dev with Connect-AzAccount
VisualStudio	VisualStudioCredential	Local dev from Visual Studio
InteractiveBrowser	InteractiveBrowserCredential	Interactive scenarios (not for production)
None	No authentication	Local emulator only

User-assigned managed identity example:

Endpoint=https://myscheduler.westus3.durabletask.io;TaskHub=default;Authentication=ManagedIdentity;ClientId=00000000-0000-0000-0000-000000000000

Concurrency Settings

Control how many work items are processed in parallel:

Property	Default	Description
MaxConcurrentOrchestrationWorkItems	ProcessorCount * 10	Max parallel orchestration executions
MaxConcurrentActivityWorkItems	ProcessorCount * 10	Max parallel activity executions

var options = AzureManagedOrchestrationServiceOptions.FromConnectionString(connectionString);
options.MaxConcurrentOrchestrationWorkItems = 50;
options.MaxConcurrentActivityWorkItems = 100;

Large Payload Storage

For payloads exceeding gRPC message limits, configure Azure Blob Storage to externalize large data:

var options = AzureManagedOrchestrationServiceOptions.FromConnectionString(connectionString);
options.LargePayloadStorageOptions = new LargePayloadStorageOptions("UseDevelopmentStorage=true")
{
    ExternalizeThresholdBytes = 1024,      // Externalize payloads larger than 1KB
    MaxExternalizedPayloadBytes = 4194304, // Max 4MB payload size
    CompressPayloads = true                // Compress before storing (default: true)
};

Property	Description
Constructor (connectionString)	Azure Storage connection string or "UseDevelopmentStorage=true" for local dev
ExternalizeThresholdBytes	Payloads larger than this are stored in blob storage
MaxExternalizedPayloadBytes	Maximum allowed payload size (fails fast if exceeded)
CompressPayloads	Whether to compress payloads before storing (improves storage efficiency)

When enabled, large orchestration inputs, outputs, activity results, and event payloads are automatically stored in blob storage and retrieved transparently.

Additional Options

Property	Default	Description
TaskHubName	"default"	Name of the task hub (usually set via connection string)
OrchestrationHistoryCacheExpirationPeriod	10 minutes	How long orchestration history is cached in memory
ResourceId	https://durabletask.io	OAuth resource ID (change only for sovereign clouds)

Local Development with Emulator

For local development, use the Docker-based emulator:

docker pull mcr.microsoft.com/dts/dts-emulator:latest
docker run -d -p 8080:8080 -p 8082:8082 mcr.microsoft.com/dts/dts-emulator:latest

Connect to the emulator:

var connectionString = "Endpoint=http://localhost:8080;TaskHub=default;Authentication=None";
var service = new AzureManagedOrchestrationService(
    AzureManagedOrchestrationServiceOptions.FromConnectionString(connectionString),
    loggerFactory);

Access the local dashboard at: http://localhost:8082

Samples

For complete working examples, see the Durable Task Scheduler samples repository.

Additional Resources

• Azure Documentation — Creating resources, configuration, SKUs, RBAC, pricing
• Quickstart Guide
• Azure Samples Repository
• Support — Enterprise support options

Next Steps

• Choosing a Backend — Compare all providers
• Quickstart — Create your first orchestration
• Core Concepts — Learn the fundamentals