Keeping packages up-to-date

Keeping Docker images up-to-date makes them more secure because applications might have released security updates since the image was released. This means even when using an image from a trusted source, we should update all the software on the image before using it in a production environment.

Exactly how you can update all software on an image depends on the image and its operating system. Let's learn how to update all packages on Ubuntu using the apt-get package.

First, start a container from the ubuntu image while setting the correct flag to get an interactive session in the container.
In the Ubuntu container, run apt-get update to make the apt-get package manager check if any updates are available for any packages.
Run apt-get upgrade to upgrade all installed packages.

Before confirming the upgrade, you'll be able to see the various reasons the package will be changed. What are the reasons?

This exercise is part of the course

Introduction to Docker

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This exercise is part of the course

Introduction to Docker

IntermediateSkill Level

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You'll go from starting and stopping your first container to seeing how to clean your environment by removing all containers and images. You'll see how to debug issues by running commands inside a container or executing bash commands in a container interactively. All of this is done using the Docker Command Line Interface.

Exercise 1: Running Docker containers Exercise 2: Running your first container Exercise 3: Running a container in the background Exercise 4: An interactive container Exercise 5: Working with Docker containers Exercise 6: Helping a colleague Exercise 7: Cleaning up containers Exercise 8: Managing local docker images Exercise 9: Pulling your first image Exercise 10: Pulling a specific tag Exercise 11: Cleaning up images

Once you are able to manage images and containers, it's time to know how to share images with colleagues or your entire company and to understand how to create your own. Now, you'll build your own images using Dockerfiles. Dockerfiles are text files that include everything needed for Docker to build an image. You'll learn how to create images and will get an introduction to all the essential Dockerfile instructions like FROM, RUN, COPY, and more. By the end of this chapter, you'll have insight into how Docker makes images and be able to create optimized Docker images from scratch.

Exercise 1: Distributing Docker Images Exercise 2: Sharing your work using a Docker registry Exercise 3: Saving an image to a file Exercise 4: Receiving Docker Images Exercise 5: Creating your own Docker images Exercise 6: Building your first image Exercise 7: Working in the command-line Exercise 8: Editing a Dockerfile Exercise 9: Creating your own Dockerfile Exercise 10: Managing files in your image Exercise 11: Copying files into an image Exercise 12: Copying folders Exercise 13: Working with downloaded files Exercise 14: Choosing a start command for your Docker image Exercise 15: Overriding the default command Exercise 16: Pulling a specific tag Exercise 17: Adding a CMD

In this final chapter, you’ll focus on making your Dockerfiles configurable and secure. You'll learn how to make your Dockerfiles configurable using the ARG and ENV instructions. You’ll see why changing the user in your images makes them more secure and how to use the USER Dockerfile instruction to do so. To wrap things up, you’ll learn about some essential security best practices when creating Docker Images.

Exercise 1: Introduction to Docker caching Exercise 2: Docker caching Exercise 3: Ordering Dockerfile instructions Exercise 4: Changing users and working directory Exercise 5: WORKDIR and USER Exercise 6: Setting the user Exercise 7: Setting the working directory Exercise 8: Variables in Dockerfiles Exercise 9: Understanding ARG and ENV Exercise 10: Overriding ARG in a build Exercise 11: Changing behavior when starting a container Exercise 12: Creating Secure Docker Images Exercise 13: Security best practices Exercise 14: Keeping packages up-to-date

Current Exercise

Exercise 15: Be safe, don't use root