MSDN Documentation

Azure Container Instances Concepts

Understand the core concepts behind running containers in Azure without managing virtual machines.

Introduction to Azure Container Instances (ACI)

Azure Container Instances (ACI) provides the fastest and simplest way to run a container in Azure. It allows you to run containers without managing underlying virtual machines or having to adopt a higher-level service like Azure Kubernetes Service (AKS).

ACI is ideal for scenarios such as:

  • App modernization
  • Run containers on demand
  • Data processing and streaming
  • Build tasks and CI/CD
  • Simple web apps

With ACI, you can deploy containers quickly and easily, paying only for the compute resources your containers consume. This makes it a cost-effective solution for many application development and deployment needs.

Key Concepts

Containers

A container is a lightweight, standalone, executable package of software that includes everything needed to run it: code, runtime, system tools, system libraries, and settings.

ACI abstracts away the complexity of container orchestration, allowing you to focus on deploying and running individual containers or small groups of containers.

Container Groups

A container group is the smallest deployable compute resource in Azure that you can create and manage. It's a collection of one or more containers that share the same network namespace, storage, and lifecycle. Containers within a group are scheduled together on the same host machine.

Every container group must have at least one container. You can define multiple containers within a single group, which can communicate with each other via localhost.

Container Images

A container image is a read-only template that contains the instructions for creating a container. Images are built in layers and are the foundation of containers. ACI supports images from public registries like Docker Hub and private registries like Azure Container Registry.

When you deploy a container, you specify the container image to use. ACI pulls this image from the registry and uses it to create your container.

Resource Definitions

When you create a container group, you define the resources it will consume. This includes:

  • CPU: The number of CPU cores allocated.
  • Memory: The amount of RAM allocated (e.g., 1 GiB, 2 GiB).
  • GPU: For GPU-accelerated workloads, you can specify the number and type of GPUs.

ACI guarantees that these resources are available to your container group. You pay for the resources you allocate.

Networking

Each container group is assigned a private IP address and can optionally be assigned a public IP address. This allows your containers to communicate within your virtual network or be accessible from the internet.

You can configure DNS names for your public IP addresses, making your containers easily discoverable. Port mapping is also supported to expose specific ports from your containers to the network.

Volumes

ACI supports several types of volumes to persist data or share data between containers in a group:

  • Azure Files: Mount an Azure Files share to provide persistent storage that can be accessed by multiple containers.
  • Empty Directory: Create an empty directory that can be used for temporary storage or inter-container communication.
  • Git Repository: Mount a Git repository to deploy code directly into a container.

Management and Monitoring

ACI provides integration with Azure Monitor for logging and metrics. You can view container logs in near real-time to troubleshoot issues or monitor application behavior. Metrics provide insights into resource utilization like CPU and memory.

You can manage container groups using the Azure portal, Azure CLI, Azure PowerShell, or programmatically via the Azure SDKs and REST API.

Common Use Cases for ACI

  • Dev/Test Environments: Quickly spin up containers for testing without the overhead of VM management.
  • CI/CD Pipelines: Use ACI for build agents or to run short-lived tasks in your continuous integration and continuous deployment workflows.
  • Web Applications: Host simple, stateless web applications that don't require complex orchestration.
  • Data Processing: Run batch jobs or data transformation tasks.
  • Event-Driven Architectures: Trigger containers to run in response to events.
  • AI/ML Inference: Deploy machine learning models for inference workloads.

Getting Started with ACI

To get started with Azure Container Instances, you'll typically follow these steps:

  1. Prerequisites: Ensure you have an Azure subscription.
  2. Create a Container Image: Build your application into a container image.
  3. Push to a Registry: Push your image to a container registry like Azure Container Registry (ACR) or Docker Hub.
  4. Deploy with Azure CLI: Use the Azure CLI to create a container group. For example: 
    
az container create --resource-group myResourceGroup --name mycontainer --image myacr.azurecr.io/myapp:v1 --dns-name-label myapp
  5. Monitor and Manage: Use the Azure portal or Azure CLI to view logs, metrics, and manage your container instances.

Explore the tutorials section for detailed step-by-step guides.