Serverless computing is a cloud service where the cloud provider dynamically allocates infrastructure to run your code. Your provider scales hardware dynamically based on your usage and deallocates hardware when your code isn’t running. Pricing is based on your usage.
Businesses worldwide are rapidly embracing cloud computing. That means our software and hardware environments are changing. Companies no longer need on-premises hardware, or need significantly less of it. Infrastructure and software are deployed using scripts and continuous deployment. However, whether you have a physical server, an on-premise virtual machine (VM), or a VM in the cloud, you still need to maintain the server, install updates, and troubleshoot issues. No matter how or where you host your infrastructure, you’ll always need maintenance.
The cloud has four types of cloud services. Hosting infrastructure in the cloud is also called infrastructure as a service (IaaS). It’s easier to run applications on a predefined host and leave the infrastructure to your cloud provider, but options are more limited. They provide a middleware on top of your infrastructure that makes software run out of the box. Such platforms are named platform as a service (PaaS). Another step “up” is using software in the cloud, such as Office 365 or Dynamics 365. This is called software as a service (SaaS), and is not offered in Azure directly. The fourth and last cloud service is serverless.
Infrastructure as a service (IaaS)
One reason to use VMs in the cloud is that it’s easy to grab your on-premises VM and move it to the cloud. You can run all of your on-premises workloads, except they now run in the cloud. VMs give you the freedom to install whatever you want, but at the cost of having to maintain your own server.
Platform as a service (PaaS)
With platform as a service, the maintenance effort is significantly reduced. In Azure this would typically be an app service with a hosting plan. Instead of hosting software on a server or VM, you can host software in the cloud and not worry too much about server maintenance. You still rent some server space for your application to run on, but the server is maintained by your cloud provider. You must decide on a server plan, for example, one with at least 2 GB of memory and four cores (or compute units). After that, you have to monitor if your service plan is enough and plan for upscaling (increase memory and/or compute units) or out-scaling (adding additional instances) if it isn’t. Additionally, you can set some settings like Always On, HTTPS Only, certificates and authentication, and authorization using the intuitive Azure portal.
While PaaS is easier than IaaS, it does have its downsides. On a VM you can install anything you want, but on an App Service, not so much.
Serverless
Serverless is the next step in this evolution. You get even less control over your environment, but with some great benefits. First, serverless is a bit of a misnomer. Of course, your code still runs on servers, but you have minimum control over them. In fact, when your code isn’t running, the server is allocated to other Azure users who need to run their code. The code for your serverless applications is stored in an Azure storage account and started up when it is somehow triggered.
Azure offers several serverless services that operate on a consumption-based model, meaning you only pay for what you use.
Azure provides a variety of serverless services to help you build and deploy applications without having to manage infrastructure. Here are some of the key serverless services available on Azure:
- Azure Functions: A serverless compute service that lets you run event-triggered code without having to provision or manage infrastructure.
- Azure Logic Apps: A cloud service that helps you schedule, automate, and orchestrate tasks, business processes, and workflows when you need to integrate apps, data, systems, and services across enterprises or organizations.
- Azure Event Grid: A fully managed event routing service that allows for uniform event consumption using a publish-subscribe model.
- Azure API Management: A turnkey solution for publishing APIs to external and internal customers.
- Azure Blob Storage: A massively scalable and secure object storage for cloud-native workloads, archives, data lakes, high-performance computing, and machine learning.
- Azure Cosmos DB: A globally distributed, multi-model database service for any scale.
- Azure SignalR Service: A fully-managed service that allows you to focus on building real-time web experiences without worrying about capacity provisioning, reliable connections, scaling, encryption or authentication.
- Azure Container Apps: A serverless container service that enables you to build and deploy modern apps.