Book Image

Learning Docker - Second Edition

By : Vinod Singh, Pethuru Raj, Jeeva S. Chelladhurai
Book Image

Learning Docker - Second Edition

By: Vinod Singh, Pethuru Raj, Jeeva S. Chelladhurai

Overview of this book

Docker is an open source containerization engine that offers a simple and faster way for developing and running software. Docker containers wrap software in a complete filesystem that contains everything it needs to run, enabling any application to be run anywhere – this flexibily and portabily means that you can run apps in the cloud, on virtual machines, or on dedicated servers. This book will give you a tour of the new features of Docker and help you get started with Docker by building and deploying a simple application. It will walk you through the commands required to manage Docker images and containers. You’ll be shown how to download new images, run containers, list the containers running on the Docker host, and kill them. You’ll learn how to leverage Docker’s volumes feature to share data between the Docker host and its containers – this data management feature is also useful for persistent data. This book also covers how to orchestrate containers using Docker compose, debug containers, and secure containers using the AppArmor and SELinux security modules.
Table of Contents (13 chapters)

The docker attach command

The docker attach command attaches the running container and it is very helpful when you want to see what is written in stdout in real time:

$ sudo docker run -d --name=newtest alpine /bin/sh -c "while true; do sleep 2; df -h; done"
Unable to find image 'alpine:latest' locally
latest: Pulling from library/alpine
3690ec4760f9: Pull complete
Digest: sha256:1354db23ff5478120c980eca1611a51c9f2b88b61f24283ee8200bf9a54f2e5c
1825927d488bef7328a26556cfd72a54adeb3dd7deafb35e317de31e60c25d67
$ sudo docker attach newtest
Filesystem Size Used Available Use% Mounted on
none 7.7G 3.2G 4.1G 44% /
tmpfs 496.2M 0 496.2M 0% /dev
tmpfs 496.2M 0 496.2M 0% /sys/fs/cgroup
/dev/xvda1 7.7G 3.2G 4.1G 44% /etc/resolv.conf
/dev/xvda1 7.7G 3.2G ...