Book Image

Learn Docker - Fundamentals of Docker 18.x

By : Dr. Gabriel N. Schenker
Book Image

Learn Docker - Fundamentals of Docker 18.x

By: Dr. Gabriel N. Schenker

Overview of this book

Docker containers have revolutionized the software supply chain in small and big enterprises. Never before has a new technology so rapidly penetrated the top 500 enterprises worldwide. Companies that embrace containers and containerize their traditional mission-critical applications have reported savings of at least 50% in total maintenance cost and a reduction of 90% (or more) of the time required to deploy new versions of those applications. Furthermore they are benefitting from increased security just by using containers as opposed to running applications outside containers. This book starts from scratch, introducing you to Docker fundamentals and setting up an environment to work with it. Then we delve into concepts such as Docker containers, Docker images, Docker Compose, and so on. We will also cover the concepts of deployment, orchestration, networking, and security. Furthermore, we explain Docker functionalities on public clouds such as AWS. By the end of this book, you will have hands-on experience working with Docker containers and orchestrators such as SwarmKit and Kubernetes.
Table of Contents (21 chapters)
Title Page
Packt Upsell
Contributors
Preface
Index

Pruning unused resources


Once we have concluded that some clean up is needed Docker provides us with so-called pruning commands. For each resource, such as images, containers, volumes, and networks there exists a prune command.

Pruning containers

In this section we want to regain unused system resources by pruning containers. Let's start with this command:

$ docker container prune

The preceding command will remove all containers from the system that are not in running status. Docker will ask for confirmation before deleting the containers that are currently in  exited or created status. If you want to skip this confirmation step you can use the -f (or --force) flag:

$ docker container prune -f

Under certain circumstances, we might want to remove all containers from our system, even the running ones. We cannot use the prune command for this. Instead we should use a command, such as the following combined expression:

$ docker container rm -f $(docker container ls -aq) 

Please be careful with the preceding...