Docker

Last modified: August 27, 2024

Introduction

Docker is an open source container technology. With Mendix, you can use it for simple deployments, particularly when running local or development versions of your app. However, it lacks some scaling and integration features.

The Docker Buildpack simplifies the creation of Docker images locally, but it falls short in terms of running, managing, and operating them effectively compared to the capabilities offered by Mendix for Private Cloud. Leveraging Mendix for Private Cloud means entrusting the Mendix Operator to automate these essential tasks whenever Kubernetes handles your containers. The following diagram illustrates the disparity between Docker Buildpack and Mendix Operator:

This page explains how to build a Docker image from your Mendix App. Every time you make changes to your app, you must create a new Docker image that can be pushed through the different stages of your application pipeline.

This how-to teaches you how to do the following:

  • Build the image
  • Push the image to a registry

Prerequisites

Before starting these instructions, make sure you have completed the following prerequisites:

Building the Image

To build the Docker image, follow these steps:

  1. Install Docker on your computer.

  2. Restart the computer to ensure that you have been granted access to Docker.

  3. Unzip the buildpack into a location of your choice.

  4. Open the Command Prompt and navigate to the folder where you unzipped the buildpack.

  5. Open your app in Studio Pro and select the menu option App > Show App Directory in Explorer:

  6. Copy the project folder and all its subfolders to the unzipped docker build folder. The project folder needs to be in the same folder as the Docker file, otherwise Docker cannot access it.

  7. Execute the following command:

    docker build --build-arg BUILD_PATH="{relative-mendix-project-location}" -t {image name} .

    {relative-mendix-project-location} is the BUILD_PATH which indicates where the application model is located. It is the directory where your .MPR file is located after you copied the project into the docker build folder. If you do not specify it, it defaults to ./project.

    A successful build will resemble the output shown below:

Pushing the Image

A new Docker image has been created with the name ({image name}) you gave it. You can see the image by using the command docker images.

Next, you need to push the image to a registry. This can be a public registry or your own. To push it to your own registry, use the command docker push {image name}.

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