.NET Aspire Community Toolkit Ollama integration

Includes: Hosting integration and Client integration

Ollama is a powerful, open source language model that can be used to generate text based on a given prompt. The .NET Aspire Ollama integration provides a way to host Ollama models using the docker.io/ollama/ollama container image and access them via the OllamaSharp client.

The Ollama hosting integration models an Ollama server as the OllamaResource type, and provides the ability to add models to the server using the AddModel extension method, which represents the model as an OllamaModelResource type. To access these types and APIs that allow you to add the 📦 CommunityToolkit.Aspire.Hosting.Ollama NuGet package in the app host project.

dotnet add package CommunityToolkit.Aspire.Hosting.Ollama

<PackageReference Include="CommunityToolkit.Aspire.Hosting.Ollama"
                  Version="*" />

For more information, see dotnet add package or Manage package dependencies in .NET applications.

In the app host project, register and consume the Ollama integration using the AddOllama extension method to add the Ollama container to the application builder. You can then add models to the container, which downloads and run when the container starts, using the AddModel extension method.

var builder = DistributedApplication.CreateBuilder(args);

var ollama = builder.AddOllama("ollama");

var phi35 = ollama.AddModel("phi3.5");

var exampleProject = builder.AddProject<Projects.ExampleProject>()
                            .WithReference(phi35);

Alternatively, if you want to use a model from the Hugging Face model hub, you can use the AddHuggingFaceModel extension method.

var llama = ollama.AddHuggingFaceModel("llama", "bartowski/Llama-3.2-1B-Instruct-GGUF:IQ4_XS");

When .NET Aspire adds a container image to the app host, as shown in the preceding example with the docker.io/ollama/ollama image, it creates a new Ollama instance on your local machine. For more information, see Container resource lifecycle.

When the Ollama container for this integration first spins up, it downloads the configured LLMs. The progress of this download displays in the State column for this integration on the .NET Aspire dashboard.

One or more LLMs are downloaded into the container which Ollama is running from, and by default this container is ephemeral. If you need to persist one or more LLMs across container restarts, you need to mount a volume into the container using the WithDataVolume method.

var ollama = builder.AddOllama("ollama")
                    .WithDataVolume();

var llama = ollama.AddModel("llama3");

One or more LLMs are downloaded into the container which Ollama is running from, and by default this container runs on CPU. If you need to run the container in GPU you need to pass a parameter to the container runtime args.

var ollama = builder.AddOllama("ollama")
                    .AddModel("llama3")
                    .WithContainerRuntimeArgs("--gpus=all");

var ollama = builder.AddOllama("ollama")
                    .AddModel("llama3")
                    .WithContainerRuntimeArgs("--device", "nvidia.com/gpu=all");

The Ollama hosting integration automatically adds a health check for the Ollama server and model resources. For the Ollama server, a health check is added to verify that the Ollama server is running and that a connection can be established to it. For the Ollama model resources, a health check is added to verify that the model is running and that the model is available, meaning the resource will be marked as unhealthy until the model has been downloaded.

The Ollama integration also provided support for running Open WebUI and having it communicate with the Ollama container.

var ollama = builder.AddOllama("ollama")
                    .AddModel("llama3")
                    .WithOpenWebUI();

To get started with the .NET Aspire OllamaSharp integration, install the 📦 CommunityToolkit.Aspire.OllamaSharp NuGet package in the client-consuming project, that is, the project for the application that uses the Ollama client.

dotnet add package CommunityToolkit.Aspire.OllamaSharp

<PackageReference Include="CommunityToolkit.Aspire.OllamaSharp"
                  Version="*" />

In the Program.cs file of your client-consuming project, call the AddOllamaClientApi extension to register an IOllamaClientApi for use via the dependency injection container. If the resource provided in the app host, and referenced in the client-consuming project, is an OllamaModelResource, then the AddOllamaClientApi method will register the model as the default model for the IOllamaClientApi.

builder.AddOllamaClientApi("llama3");

After adding IOllamaClientApi to the builder, you can get the IOllamaClientApi instance using dependency injection. For example, to retrieve your context object from service:

public class ExampleService(IOllamaClientApi ollama)
{
    // Use ollama...
}

There might be situations where you want to register multiple IOllamaClientApi instances with different connection names. To register keyed Ollama clients, call the AddKeyedOllamaClientApi method:

builder.AddKeyedOllamaClientApi(name: "chat");
builder.AddKeyedOllamaClientApi(name: "embeddings");

Then you can retrieve the IOllamaClientApi instances using dependency injection. For example, to retrieve the connection from an example service:

public class ExampleService(
    [FromKeyedServices("chat")] IOllamaClientApi chatOllama,
    [FromKeyedServices("embeddings")] IOllamaClientApi embeddingsOllama)
{
    // Use ollama...
}

The Ollama client integration provides multiple configuration approaches and options to meet the requirements and conventions of your project.

When using a connection string from the ConnectionStrings configuration section, you can provide the name of the connection string when calling the AddOllamaClientApi method:

builder.AddOllamaClientApi("llama");

Then the connection string will be retrieved from the ConnectionStrings configuration section:

{
  "ConnectionStrings": {
    "llama": "Endpoint=http//localhost:1234;Model=llama3"
  }
}

The Microsoft.Extensions.AI library provides an abstraction over the Ollama client API, using generic interfaces. OllamaSharp supports these interfaces, and they can be registered using the AddOllamaSharpChatClient and AddOllamaSharpEmbeddingGenerator extension methods. These methods will also register the IOllamaClientApi instances with the dependency injection container, and have keyed versions for multiple instances.

builder.AddOllamaSharpChatClient("llama");

After adding IChatClient to the builder, you can get the IChatClient instance using dependency injection. For example, to retrieve your context object from service:

public class ExampleService(IChatClient chatClient)
{
    // Use chat client...
}

• Ollama
• Open WebUI
• .NET Aspire Community Toolkit GitHub repo
• OllamaSharp
• Microsoft.Extensions.AI