resolve most of my comments

Signed-off-by: Sven Dowideit <SvenDowideit@home.org.au>
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Sven Dowideit 2015-01-30 21:27:57 +10:00
parent 461f1ad5d5
commit 3b7ea5c055
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page_title: Compose: Multi-container orchestration for Docker
page_description: Introduction and Overview of Compose
page_keywords: documentation, docs, docker, compose, orchestration, containers
page_keywords: documentation, docs, docker, compose, orchestration, containers
## Overview
Compose is a tool that allows you to orchestrate multiple Docker containers. With Compose, you can build clusters of containers which provide the resources (services, volumes, etc.) needed to build and run a complete distributed application.
Compose is a tool that allows you to orchestrate multiple Docker containers.
With Compose, you can build clusters of containers which provide the resources
(services, volumes, etc.) needed to build and run a complete distributed
application.
You can use Compose to build your app with containers hosted locally, or on a remote server, including cloud-based instances. Compose can also be used to deploy code to production.
You can use Compose to build your app with containers hosted locally, or on a
remote server, including cloud-based instances. Compose can also be used to
deploy code to production.
Using Compose is basically a three-step process.
First, you define your app's environment with a `Dockerfile` so it can be reproduced anywhere:
First, you define your app's environment with a `Dockerfile` so it can be
reproduced anywhere:
FROM python:2.7
ADD . /code
WORKDIR /code
ADD rements.txt /code/
RUN pip install -r requirements.txt
ADD . /code
Next, you define the services that make up your app in `docker-compose.yml` so they can be run together in an isolated environment:
Next, you define the services that make up your app in `docker-compose.yml` so
they can be run together in an isolated environment:
```yaml
web:
@ -46,7 +54,10 @@ Compose includes commands to:
## Quick start
Let's get started with a walkthrough of getting a simple Python web app running on Compose. It assumes a little knowledge of Python, but the concepts demonstrated here should be understandable even if you're not familiar with Python.
Let's get started with a walkthrough of getting a simple Python web app running
on Compose. It assumes a little knowledge of Python, but the concepts
demonstrated here should be understandable even if you're not familiar with
Python.
### Installation and set-up
@ -84,7 +95,8 @@ Next, define the Python dependencies in a file called `requirements.txt`:
### Create a Docker image
Now, create a Docker image containing all of your app's dependencies. You
specify how to build the image using a file called [`Dockerfile`](http://docs.docker.com/reference/builder/):
specify how to build the image using a file called
[`Dockerfile`](http://docs.docker.com/reference/builder/):
FROM python:2.7
ADD . /code
@ -93,7 +105,9 @@ specify how to build the image using a file called [`Dockerfile`](http://docs.do
This tells Docker to include Python, your code, and your Python dependencies in
a Docker image. For more information on how to write Dockerfiles, see the
[Docker user guide](https://docs.docker.com/userguide/dockerimages/#building-an-image-from-a-dockerfile) and the
[Docker user
guide](https://docs.docker.com/userguide/dockerimages/#building-an-image-from-a-dockerfile)
and the
[Dockerfile reference](http://docs.docker.com/reference/builder/).
### Define services
@ -115,12 +129,13 @@ Next, define a set of services using `docker-compose.yml`:
This defines two services:
- `web`, which is built from the `Dockerfile` in the current directory. It also
says to run the command `python app.py` inside the image, forward the exposed
port 5000 on the container to port 5000 on the host machine, connect up the
Redis service, and mount the current directory inside the container so we can
work on code without having to rebuild the image.
- `redis`, which uses the public image [redis](https://registry.hub.docker.com/_/redis/), which gets pulled from the
Docker Hub registry.
says to run the command `python app.py` inside the image, forward the exposed
port 5000 on the container to port 5000 on the host machine, connect up the
Redis service, and mount the current directory inside the container so we can
work on code without having to rebuild the image.
- `redis`, which uses the public image
[redis](https://registry.hub.docker.com/_/redis/), which gets pulled from the
Docker Hub registry.
### Build and run your app with Compose
@ -135,8 +150,8 @@ image for your code, and start everything up:
redis_1 | [8] 02 Jan 18:43:35.576 # Server started, Redis version 2.8.3
web_1 | * Running on http://0.0.0.0:5000/
The web app should now be listening on port 5000 on your docker daemon (if
you're using boot2docker, `boot2docker ip` will tell you its address).
The web app should now be listening on port 5000 on your Docker daemon host (if
you're using Boot2docker, `boot2docker ip` will tell you its address).
If you want to run your services in the background, you can pass the `-d` flag
(for daemon mode) to `docker-compose up` and use `docker-compose ps` to see what
@ -146,7 +161,7 @@ is currently running:
Starting composetest_redis_1...
Starting composetest_web_1...
$ docker-compose ps
Name Command State Ports
Name Command State Ports
-------------------------------------------------------------------
composetest_redis_1 /usr/local/bin/run Up
composetest_web_1 /bin/sh -c python app.py Up 5000->5000/tcp
@ -164,4 +179,6 @@ your services once you've finished with them:
$ docker-compose stop
At this point, you have seen the basics of how Compose works. See the reference section for complete details on the commands, configuration file and environment variables.
At this point, you have seen the basics of how Compose works. See the reference
section for complete details on the commands, configuration file and environment
variables.