What is ACI? Microsoft’s Azure Container Instances explained


Azure is rapidly turning into a container-driven public cloud, with strategic investments in tools and hires. It’s also running fast, launching new container-focused products and services on a regular basis. At first, Azure was catching up with Amazon Web Services’ features, but the release of the new Azure rapid-deployment container service that acts as a bridge between platform as a service and infrastructure as a service leapfrogs Amazon.

Introducing container as a service

Perhaps best thought of as a new class of cloud platform — call it “container as a service”— Azure Container Instances (ACI) let you rapidly create and launch containerized applications, without any overhead and with an easily scriptable set of commands. Designed to work both on its own and with tools like Kubernetes, ACI adds container-management commands to Azure, coupling them with a billing model that’s based on per-second usage, with no need to create and deploy (and pay for) container hosts.

However, the billing model is complex, with three elements making up the charge. First, there’s a flat fee of $0.0025 per request for creating a container instance. Then, once set up, you’re billed for both memory, at $0.0000125 per gigabyte per second, and for cores used, at $0.0000125 per core per second. So, you’ll need to keep an eye on what you’re using and for how long, especially if you’re using ACI to handle scaling for a large application.

Using ACI to deploy containers

Setting up your first ACI container is easy enough, because ACI uses the Azure command line. The current version can run only Linux containers, though Windows containers should follow soon. Just as with working with Azure’s Container Service, you’ll find yourself using the Azure Cloud Shell or a remote Azure command-line instance to build and manage containers, starting by creating a resource group for your ACI containers.

to link containers into an application. Building code that works in this new environment might be more complex to start with, but using containers as your main deployment mode can simplify updates, as well as scaling.

Up to now, Microsoft’s been a fast follower on the container path, but with its recent and now its membership of the Cloud Native Computing Foundation, it looks set to shift gear and start pushing the development of containers, not just using them.