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

Consuming Docker system events


The Docker engine, when creating, running, stopping, and removing containers and other resources such as volumes or networks, produces a log of events. These events can be consumed by external systems, such as some infrastructure services that use them to make informed decisions. An example of such a service could be a tool that creates an inventory of all containers that are currently running on the system.

We can hook ourselves into this stream of system events and output them, for example in a terminal, by using the following command:

$ docker system events

This command is a blocking command. Thus, when you execute it in your terminal session the according session is blocked. Therefore, we recommend that you always open an extra window when you want to use this command.

Assuming we have executed the preceding command in an extra terminal window, we can now test it and run a container like this:

$ docker container run --rm alpine echo "Hello World"

The output produced...