Quickstart: Docker Compose and Rails This Quickstart guide will show you how to use Docker Compose to set up and run a Rails/PostgreSQL app. Before starting, you’ll need to have Compose installed. Define the project Start by setting up the three files you’ll need to build the app. First, since your app is going to run inside a Docker container containing all of its dependencies, you’ll need to define exactly what needs to be included in the container. This is done using a file called Dockerfile

Configuring and running Docker on various distributions After successfully installing Docker, the docker daemon runs with its default configuration. In a production environment, system administrators typically configure the docker daemon to start and stop according to an organization’s requirements. In most cases, the system administrator configures a process manager such as SysVinit, Upstart, or systemd to manage the docker daemon’s start and stop. Running the docker daemon directly The docker

pull Usage: docker pull [OPTIONS] NAME[:TAG] | [REGISTRY_HOST[:REGISTRY_PORT]/]NAME[:TAG] Pull an image or a repository from the registry -a, --all-tags Download all tagged images in the repository --disable-content-trust=true Skip image verification --help Print usage Most of your images will be created on top of a base image from the Docker Hub registry. Docker Hub contains many pre-built images that you can pull and try without needing to defin

create Create a machine. Requires the --driver flag to indicate which provider (VirtualBox, DigitalOcean, AWS, etc.) the machine should be created on, and an argument to indicate the name of the created machine. $ docker-machine create --driver virtualbox dev Creating CA: /home/username/.docker/machine/certs/ca.pem Creating client certificate: /home/username/.docker/machine/certs/cert.pem Image cache does not exist, creating it at /home/username/.docker/machine/cache... No default boot2docker i

Extending services and Compose files Compose supports two methods of sharing common configuration: Extending an entire Compose file by using multiple Compose files Extending individual services with the extends field Multiple Compose files Using multiple Compose files enables you to customize a Compose application for different environments or different workflows. Understanding multiple Compose files By default, Compose reads two files, a docker-compose.yml and an optional docker-compose.ov

Dockerfile reference Docker can build images automatically by reading the instructions from a Dockerfile. A Dockerfile is a text document that contains all the commands a user could call on the command line to assemble an image. Using docker build users can create an automated build that executes several command-line instructions in succession. This page describes the commands you can use in a Dockerfile. When you are done reading this page, refer to the Dockerfile Best Practices for a tip-orie

Overview of Docker Compose Compose is a tool for defining and running multi-container Docker applications. With Compose, you use a Compose file to configure your application’s services. Then, using a single command, you create and start all the services from your configuration. To learn more about all the features of Compose see the list of features. Compose is great for development, testing, and staging environments, as well as CI workflows. You can learn more about each case in Common Use Cas

Configure container DNS The information in this section explains configuring container DNS within the Docker default bridge. This is a bridge network named bridge created automatically when you install Docker. Note: The Docker networks feature allows you to create user-defined networks in addition to the default bridge network. Please refer to the Docker Embedded DNS section for more information on DNS configurations in user-defined networks. How can Docker supply each container with a hostna

Use the Docker command line To list available commands, either run docker with no parameters or execute docker help: $ docker Usage: docker [OPTIONS] COMMAND [arg...] docker daemon [ --help | ... ] docker [ --help | -v | --version ] -H, --host=[]: The socket(s) to talk to the Docker daemon in the format of tcp://host:port/path, unix:///path/to/socket, fd://* or fd://socketfd. A self-sufficient runtime for Linux containers. ... Depending on your Docker system conf

Docker Swarm Discovery Docker Swarm comes with multiple discovery backends. You use a hosted discovery service with Docker Swarm. The service maintains a list of IPs in your cluster. This page describes the different types of hosted discovery available to you. These are: Using a distributed key/value store The recommended way to do node discovery in Swarm is Docker’s libkv project. The libkv project is an abstraction layer over existing distributed key/value stores. As of this writing, the proj