Running Containers on Azure Container Instances with Docker

If you already use Docker, then you’ve probably run a container on your machine. But have you ever imagined what it would be like if you could run a container directly on cloud infrastructure without doing anything new?

Last month, the Docker team announced that the new versions of Docker for desktop (called Edge versions) would gain native support for Azure Container Instances, meaning we could run containers from our machine directly to a cloud environment without having to download any image locally!

Azure Container Instances#

Azure Container Instances (ACI) is one of the products offered by Azure that allows you to deploy an application in a container without worrying about virtual machines or any other kind of infrastructure.

I’ve used ACI when we did a talk for #CodeInQuarentena. In the video below you can see where we created a complete API using Mongoke and ACI

Essentially, ACI is a way for you to run your application as a container online. That way the only thing you need is an Azure account and an application that’s already inside a container. The best part is that everything is charged by the second of usage, so you don’t really pay for idle compute. Which is excellent for applications that need to be created and destroyed quickly.

But how can ACI be integrated with Docker?

Integrating ACI with Docker#

Let’s integrate Docker with ACI. Assuming you already have an Azure account and know a bit about Docker, what you need to do is download Docker Edge.

Docker Edge#

Docker Edge is an experimental version of Docker that receives all updates that haven’t yet been released in the general availability version. For the integration with ACI to happen, since it’s still an experimental flag, we need to download the Docker Edge version. This repository has all the necessary links for installation on various platforms.

If you already have Docker installed on your machine, you’ll need to remove the official CE version and install Docker Edge. It’s not possible to have both versions installed on the same machine.

Once Docker is installed, you should see this screen:

Check the Command Line tab to see if you have the Enable Cloud Experience option enabled:

With that you already have the integration active, now what we need to do is create a context!

Docker Context#

Docker contexts are not a new feature. The purpose of contexts is to allow you to change where you’re working. This became particularly interesting after the advent of Kubernetes for Docker, because with contexts you can switch between using the Docker engine, Kubernetes within Docker, or even a Docker Swarm context.

With ACI it’s no different, we need to create a context for cloud integration! This is quite simple, first we need to log in to Azure using the following command:

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$ docker login azure

After that, you’ll be taken to the Azure website to log in, and once that’s complete, you can go back to the CLI and run the following command:

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$ docker context create aci nome-do-contexto

Next you’ll need to choose your subscription and then the resource group that will be used to push the images. Once done, you can run the docker context ls command to see all existing contexts and your integration is complete!

Creating a container#

To run this example, we’re going to use a public image I have on Docker Hub called Simple Node API.

Let’s start by switching our context to the new context we created using the command docker context use <context-name>.

To deploy, we can run the command we’re used to, docker run:

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$ docker run -d -p 80:80 --name node-api -e PORT=80 khaosdoctor/simple-node-api

Here’s the output we’ll get:

To find the address we need to access to see our API online, we’ll run docker ps and look for the contents of PORTS.

See that I need to access the IP 13.86.141.148 to see the API result in the browser, let’s go!

See that if we access the Azure portal, we’ll have our resource created as if we had created it manually!

To remove it, just run the command docker rm <name>. Note that it’s not possible to run the docker stop command because this type of integration doesn’t allow us to stop the container remotely. If we run docker rm node-api we’ll have our ACI removed from Azure and our container stopped!

Other applications#

We can also use ACI to create multi-container applications using Docker Compose. For this, we’ll use the example that Docker gives us from the DockerCon website! We have the following YAML file:

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version: '3.3'
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services:
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  db:
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    image: bengotch/acidemodb
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  words:
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    image: bengotch/acidemowords
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  web:
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    image: bengotch/acidemoweb
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    ports:
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      - "80:80"

We follow the same process. However, instead of running the docker run command we’ll run the docker compose up -d command.

Note that we don’t have a - between docker and compose as you would expect when running the command locally. That’s because compose is a command of the integration itself!

Then we can use the docker ps command normally to get the public IP and see the site live:

Limitations#

• ACI does not support port mapping, so you need to make sure your container is running on the same port on both the host and the container using the -p port:port flag (see this issue)
• Not all commands present in Docker are present in the integration (see this other issue for more details)

Conclusion#

With ACI integration we can integrate much faster with Azure and this greatly facilitates the development of cloud-focused applications! Try it yourself!

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