Azure offers a number of ways to host your application code. The term compute refers to the hosting model for the computing resources that your application runs on. The following flowchart will help you to choose a compute service for your application.
If your application consists of multiple workloads, evaluate each workload separately. A complete solution may incorporate two or more compute services.
The word compute here refers to the hosting model for the computing resources on which our application runs. Azure compute service can be divided broadly into three categories.
Infrastructure as a service
Platform as a service
Serveless services
The most fundamental building block is the Azure virtual machine. Using Azure virtual machine, we can able to deploy different services such as Windows, Linux within the Azure cloud. When we implement a virtual machine, every virtual machine will have an associated OS and data disk.
Azure Compute Options
Virtual Machine
It is an IaaS service, allowing us to deploy and manage VMs inside a virtual network (VNet).
App Service
It is a managed PaaS offering for hosting web apps, mobile app back ends, RESTful APIs, or automated business processes.
Service Fabric
It is a platform that can run on any environment, including Azure or on-premises. It is an orchestrator of micro-services across a cluster of machine
Azure Kubernetes Services
It manages a hosted Kubernetes service for running containerized applications.
Azure Container Instances
It offers the fastest and most straightforward way to run a container in Azure without having to provision any virtual machines and without having to adopt a high-level service.
Azure Functions
It is a managed FaaS service.
Azure Batch
It is a managed service for running large-scale parallel and high-performance computing (HPC) applications.
Cloud Services
It is a managed service for running cloud applications. It uses a PaaS hosting model.
Choose an Azure compute service
Definitions
· "Lift and shift" is a strategy for migrating a workload to the cloud without redesigning the application or making code changes. Also called rehosting.
· Cloud optimized is a strategy for migrating to the cloud by refactoring an application to take advantage of cloud-native features and capabilities.
The output from this flowchart is a starting point for consideration. Next, perform a more detailed evaluation of the service to see if it meets your needs.
This article includes several tables which may help you to make these tradeoff decisions. Based on this analysis, you may find that the initial candidate isn't suitable for your particular application or workload. In that case, expand your analysis to include other compute services.
Understand the basic features
If you're not familiar with the Azure service selected in the previous step, read the overview documentation to understand the basics of the service.
App Service. A managed service for hosting web apps, mobile app back ends, RESTful APIs, or automated business processes.
Azure Spring Cloud. A managed service designed and optimized for hosting Spring Boot apps.
Azure Kubernetes Service (AKS). A managed Kubernetes service for running containerized applications.
Batch. A managed service for running large-scale parallel and high-performance computing (HPC) applications
Container Instances. The fastest and simplest way to run a container in Azure, without having to provision any virtual machines and without having to adopt a higher-level service.
Functions. A managed FaaS service.
Service Fabric. A distributed systems platform that can run in many environments, including Azure or on premises.
Virtual machines. Deploy and manage VMs inside an Azure virtual network.
Understand the hosting models
Cloud services, including Azure services, generally fall into three categories: IaaS, PaaS, or FaaS. (There is also SaaS, software-as-a-service, which is out of scope for this article.) It's useful to understand the differences.
Infrastructure-as-a-Service (IaaS) lets you provision individual VMs along with the associated networking and storage components. Then you deploy whatever software and applications you want onto those VMs. This model is the closest to a traditional on-premises environment, except that Microsoft manages the infrastructure. You still manage the individual VMs.
Platform-as-a-Service (PaaS) provides a managed hosting environment, where you can deploy your application without needing to manage VMs or networking resources. Azure App Service is a PaaS service.
Functions-as-a-Service (FaaS) goes even further in removing the need to worry about the hosting environment. In a FaaS model, you simply deploy your code and the service automatically runs it. Azure Functions is a FaaS service.
Scalability
Criteria | Virtual Machines | App Service | Azure Spring Cloud | Service Fabric | Azure Functions | Azure Kubernetes Service | Container Instances | Azure Batch |
Autoscaling | Virtual machine scale sets | Built-in service | Built-in service | Virtual machine scale sets | Built-in service | Pod auto-scaling1, cluster auto-scaling2 | Not supported | N/A |
Load balancer | Azure Load Balancer | Integrated | Integrated | Azure Load Balancer | Integrated | Azure Load Balancer or Application Gateway | No built-in support | Azure Load Balancer |
Platform image: 1000 nodes per scale set, Custom image: 600 nodes per scale set | 30 instances, 100 with App Service Environment | 500 app instances in Standard | 100 nodes per scale set | 200 instances per Function app | 100 nodes per cluster (default limit) | 20 container groups per subscription (default limit). | 20 core limit (default limit). |
Availability
Criteria | Virtual Machines | App Service | Azure Spring Cloud | Service Fabric | Azure Functions | Azure Kubernetes Service | Container Instances | Azure Batch |
SLA | ||||||||
Multi region failover | Traffic manager | Traffic manager | Traffic manager, Multi-Region Cluster | Traffic manager | Not supported | Not Supported | |
Other criteria
Criteria | Virtual Machines | App Service | App Spring Cloud | Service Fabric | Azure Functions | Azure Kubernetes Service | Container Instances | Azure Batch |
SSL | Configured in VM | Supported | Supported | Supported | Supported | Supported | ||
Cost | Windows, Linux | |||||||
Suitable architecture styles | N-Tier, Big compute (HPC) | Web-Queue-Worker, N-Tier | Microservices, Event-driven architecture | Microservices, Event-driven architecture | Microservices, Event-driven architecture |