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

Retrieving container logs


It is a best practice for any good application to generate some logging information that developers and operators alike can use to find out what the application is doing at a given time, and whether there are any problems to help pinpoint the root cause of the issue.

When running inside a container, the application should preferably output the log items to STDOUT and STDERR and not into a file. If the logging output is directed to STDOUT and STDERR, then Docker can collect this information and keep it ready for consumption by a user or any other external system.

To access the logs of a given container, we can use the docker container logs command. If, for example, we want to retrieve the logs of our quotes container, we can use the following expression:

$ docker container logs quotes

This will retrieve the whole log produced by the application from the very beginning of its existence.

Note

Stop, wait a second—this is not quite true, what I just said. By default, Docker...