How to run a Docker image in IBM Cloud Functions?

Introduction to Docker and IBM Cloud Functions

Docker is a popular containerization platform that allows you to package applications and their dependencies into lightweight, portable containers. These containers can then be easily deployed and run on any machine with Docker installed, making it easy to manage and scale applications.

IBM Cloud Functions is a serverless computing platform that allows you to run code in response to triggers such as HTTP requests, events, or data updates. IBM Cloud Functions can run a variety of languages, including JavaScript, Python, and Go, and it integrates seamlessly with Docker.

Using Docker with IBM Cloud Functions allows you to easily deploy and run containerized applications in a serverless environment. This can be especially useful if you have an application that requires specific dependencies or runtime environments, as you can package everything into a single Docker image and deploy it to IBM Cloud Functions.

Setting up Docker on your local machine

To start using Docker, you will need to install it on your local machine. You can find instructions for installing Docker on the Docker website.

Once Docker is installed, you can pull a Docker image from a registry such as Docker Hub. A Docker image is a packaged application or service that is ready to be run in a container.

To pull an image, use the docker pull command followed by the name of the image −

$ docker pull ubuntu
Using default tag: latest
latest: Pulling from library/ubuntu
5bed26d33875: Pull complete
...

To run a Docker image, use the docker run command followed by the name of the image −

$ docker run ubuntu
Unable to find image 'ubuntu:latest' locally
latest: Pulling from library/ubuntu
5bed26d33875: Pull complete
...

This will start a new container based on the ubuntu image and run a command in the container. By default, the docker run command will start a new container and run a command in the foreground. You can use the -d flag to run the container in the background as a daemon.

Deploying a Docker image to IBM Cloud Functions

To deploy a Docker image to IBM Cloud Functions, you will first need to create an IBM Cloud account and install the IBM Cloud CLI. You can find instructions for setting up the CLI on the IBM Cloud documentation website.

Once you have the IBM Cloud CLI installed, you can build a Docker image for IBM Cloud Functions. IBM Cloud Functions uses a specific format for Docker images, so you will need to follow the guidelines outlined in the IBM Cloud documentation.

To push the Docker image to the IBM Cloud Functions registry, use the ibmcloud fn registry command −

$ ibmcloud fn registry --create
Successfully created registry

This will create a new registry for your IBM Cloud Functions actions. You can then use the ibmcloud fn registry push command to push your Docker image to the registry −

$ ibmcloud fn registry push my-image
Successfully pushed image 'registry.ng.bluemix.net/<namespace>/my-image'

Once the image is pushed to the registry, you can create a new IBM Cloud Functions action and specify the Docker image to use. You can do this using the IBM Cloud web console, the IBM Cloud CLI, or the IBM Cloud Functions API.

Invoking an IBM Cloud Functions action

Once you have created an IBM Cloud Functions action, you can invoke it using the IBM Cloud Functions CLI, the web console, or the API.

To invoke an action using the CLI, use the ibmcloud fn action invoke command followed by the name of the action −

$ ibmcloud fn action invoke my-action
{
   "result": "Hello, World!"
}

To invoke an action from the web console, navigate to the Actions page and click the "Invoke" button for the action you want to run.

To invoke an action from the API, use the POST /api/v1/namespaces/{namespace}/actions/{name} endpoint, replacing {namespace} and {name} with the appropriate values for your action.

Example use cases for running a Docker image in IBM Cloud Functions

There are many use cases for running a Docker image in IBM Cloud Functions. Some examples include −

• Running a custom application or service in a serverless environment

• Integrating with other IBM Cloud services using the IBM Cloud Functions API

For example, you could create an IBM Cloud Functions action that runs a Docker image of a custom web application. Whenever the action is invoked, it will start a container based on the Docker image and run the web application. This allows you to easily deploy and scale your web application without having to worry about managing infrastructure.

Conclusion

In this tutorial, we have introduced the basics of running a Docker image in IBM Cloud Functions. We covered how to set up Docker on your local machine, how to build and push a Docker image to the IBM Cloud Functions registry, and how to invoke an IBM Cloud Functions action. We also discussed some example use cases for running a Docker image in IBM Cloud Functions.

Using Docker with IBM Cloud Functions can be a powerful tool for deploying and running containerized applications in a serverless environment. It allows you to easily package and manage dependencies, and it can be especially useful for integrating with other IBM Cloud services.

To learn more about Docker and IBM Cloud Functions, you can check out the IBM Cloud documentation and the Docker documentation. There are also many online resources and tutorials available that can help you learn more about these technologies.