Microservices have replaced the old Monolithic approaches of application deployment and paved a way for container technology to become very popular. Azure provides a number of options to run containers. Each of them has its own features, pricing, and complexity. Azure enhances the capability to deploy a virtual machine and enable containers in it, however for a production system it is of utter importance to use one of the below container services.

Azure Container Instance (ACI) is the simplest and quickest option to create and run containers in Azure. It is serverless and is best suitable for single-container deployments that don’t need to integrate with other Azure services (isolated containers).
Some of the features of ACI are as follows:

• Serverless: Run the containers without managing servers
• Fast startup: Launch containers in seconds.
• Billing per second: Incur costs only while the container is running. No upfront or terminations fees
• Hypervisor-level security: Isolate your application as completely as it would be in a VM.
• Custom sizes: Specify exact values for CPU cores and memory.
• Persistent storage: Mount Azure Files are shared directly to a container to retrieve and persist state.
• Linux and Windows: Schedule both Windows and Linux containers using the same API.

Since it has a billing per second model, it is not recommended for applications that need to be run at 24X7. Instead, it is a good option for the Event-driven applications, Data processing jobs, provisioning of CI-CD pipelines, etc.

Azure Web Apps is a wonderful option for creating and hosting mission critical HTTP based applications in Azure. It supports languages like .Net, .NET Core, JAVA, Ruby, Python, Node.js, PHP. This makes Azure Web Apps also a good platform for deploying containerized web applications to Azure.
In this approach, the container image is pushed to a Docker Hub or a private Azure Container Registry using CI/CD pipelines and is deployed to Azure Web Apps.

Note: Azure Container Registry is Microsoft’s solution for securely storing the container images.

Some of the features of Azure Web Apps for Containers are

• Deployment in Seconds
• Easy integration with other Azure services
• Supports auto-scaling, staging slots, and automatic deployment
• Manage environment variables
• Rich monitoring experiences
• Enhances security features like configuring SSL certificates, IP whitelisting, AD Authentication
• Helps enable CDN
• Ability to host windows and Linux based containers.

Azure Batch helps to run a large set of batch jobs on Azure. With this approach, the batch jobs are run inside the Docker compatible containers on the nodes. This is a good option for running and scheduling repetitive computing jobs.

Azure Service Fabric is a container orchestrator for managing and deploying microservices in Azure. This is the most mature platform for deploying windows based containers so that Microsoft itself uses Service Fabric for its own products like CosmosDB, Azure SQL Database, Skype for Business, Azure IoT Hubs, Azure Event Hubs, etc.
With this, the microservices are deployed across a cluster of machines. The individual machines in the cluster are known as nodes. A cluster can have both Windows and Linux based nodes.

Service Fabric Explorer provides a rich and powerful dashboard for continuously monitoring the microservices across all the clusters and its nodes.

The key features of Service Fabric are as follows:

• Has a container Orchestrator Platform which can run anywhere – Windows/Linux, On-Premise or other clouds
  Scales up to thousands of machines
• Runs anything, depends on your choice of a programming model
• Deployment in Seconds and IDE integration
• Service to Service communication
• Recovery from hardware failures, Auto Scaling
• Supports Stateful and Stateless services.
• Security and Support for Role-Based Access Control

Service Fabric Mesh provides a more simple deployment model which is completely serverless. Unlike Service Fabric, with Service Fabric Mesh there is no overhead of managing clusters and patching operations. It is Microsoft’s SaaS offering based on Service Fabric and runs only in Azure.
Service Fabric Mesh supports both Windows and Linux containers with any programming language and framework.

Azure Kubernetes Services is a managed cluster with a Kubernetes orchestrator in Azure. The Kubernetes master is fully managed by Azure and free. We only need to manage and pay for the worker nodes and any other infrastructure resources like storage and networking.
Some of the key features of AKS are as follows:

• Ability to orchestrate applications without the operational overhead
• Identity and Security Management with the integration of Azure AD
• Integrated logging and monitoring
• Elastic Scale
• Support for version upgrades
• Simplified deployment
• Security and support for Role-Based Access Control

Azure also provides AKS Dashboard which helps to manage the Azure Kubernetes Services.

Both Service Fabric and Azure Kubernetes are wonderful platforms that help in hosting and managing microservices. Both provide features like scheduling, health monitoring, scaling, service discovery, and upgrades. Service Fabric is Microsoft’s first solution for container orchestration. It is a good choice for hosting Windows Containers and has good support for .Net Framework. It focuses on running applications with .NET or Java libraries provided by Microsoft. Hence, if there is a lot of legacy .Net code and when there is a need to introduce microservice, Service Fabric is a good choice. However, if the application should be able to be hosted in other cloud providers as well, Azure Kubernetes is a better option. Or if you use Linux and want to containerize your application then Azure Kubernetes is the better option. Also, use AKS if you are using any open source tools and not the IDE supported with Azure Service Fabric. Kubernetes is itself a leading provider for containerization and has a large set of resources and documentation, whereas with Azure Service Fabric we need to rely only on Microsoft provided resources. Service Fabric also has more operational overhead around node management when compared to AKS.

In addition to all the above services, there is also Azure Red Hat OpenShift which is a fully managed deployment of OpenShift on Azure developed by both Microsoft and Red Hat.

Choosing the right container service in Azure is important and it depends on the application needs. Below are some of the use cases for each Azure offerings. Also please refer to the official Azure documentation for this.

Azure Offering

Azure Offering	Use Case
Azure Container Instance	For bursting work load
Azure Web Apps for Containers	For hosting small web applications.
Azure Batch	For running batch jobs
Azure Service Fabric	Development of Windows based Microservices or for any legacy .Net based systems.
Azure Kubernetes Services	Complex distributed applications which need to have simple deployments and efficient use of resources