|
|
@@ -1,22 +1,24 @@
|
|
|
----
|
|
|
-layout: default
|
|
|
-title: Compose: Multi-container orchestration for Docker
|
|
|
page_title: Compose: Multi-container orchestration for Docker
|
|
|
-page_description: Compose: Multi-container orchestration for Docker
|
|
|
-page_keywords: fig, composition, compose, docker
|
|
|
----
|
|
|
+page_description: Introduction and Overview of Compose
|
|
|
+page_keywords: documentation, docs, docker, compose, orchestration, containers
|
|
|
|
|
|
-# <strong class="strapline">Fast, isolated development environments using Docker.</strong>
|
|
|
|
|
|
-Define your app's environment with a `Dockerfile` so it can be reproduced anywhere:
|
|
|
+## 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.
|
|
|
+
|
|
|
+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:
|
|
|
|
|
|
FROM python:2.7
|
|
|
ADD . /code
|
|
|
WORKDIR /code
|
|
|
RUN pip install -r requirements.txt
|
|
|
|
|
|
-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:
|
|
|
@@ -32,24 +34,25 @@ db:
|
|
|
|
|
|
(No more installing Postgres on your laptop!)
|
|
|
|
|
|
-Then type `docker-compose up`, and Compose will start and run your entire app.
|
|
|
+Lastly, run `docker-compose up` and Compose will start and run your entire app.
|
|
|
|
|
|
-There are commands to:
|
|
|
+Compose includes commands to:
|
|
|
|
|
|
- - start, stop and rebuild services
|
|
|
- - view the status of running services
|
|
|
- - tail running services' log output
|
|
|
- - run a one-off command on a service
|
|
|
+ * Start, stop and rebuild services
|
|
|
+ * View the status of running services
|
|
|
+ * tail the log output of running services
|
|
|
+ * run a one-off command on a service
|
|
|
|
|
|
|
|
|
## Quick start
|
|
|
|
|
|
-Let's get a basic Python web app running on Compose. It assumes a little knowledge
|
|
|
-of Python, but the concepts should be clear if you're not familiar with it.
|
|
|
+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
|
|
|
|
|
|
First, [install Docker and Compose](install.html).
|
|
|
|
|
|
-You'll want to make a directory for the project:
|
|
|
+Next, you'll want to make a directory for the project:
|
|
|
|
|
|
$ mkdir composetest
|
|
|
$ cd composetest
|
|
|
@@ -73,25 +76,29 @@ if __name__ == "__main__":
|
|
|
app.run(host="0.0.0.0", debug=True)
|
|
|
```
|
|
|
|
|
|
-We define our Python dependencies in a file called `requirements.txt`:
|
|
|
+Next, define the Python dependencies in a file called `requirements.txt`:
|
|
|
|
|
|
flask
|
|
|
redis
|
|
|
|
|
|
-Next, we want to create a Docker image containing all of our app's dependencies.
|
|
|
-We specify how to build one using a file called `Dockerfile`:
|
|
|
+### 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/):
|
|
|
|
|
|
FROM python:2.7
|
|
|
ADD . /code
|
|
|
WORKDIR /code
|
|
|
RUN pip install -r requirements.txt
|
|
|
|
|
|
-This tells Docker to install Python, our code and our Python dependencies inside
|
|
|
+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 [Dockerfile reference](http://docs.docker.com/reference/builder/).
|
|
|
+[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
|
|
|
|
|
|
-We then define a set of services using `docker-compose.yml`:
|
|
|
+Next, define a set of services using `docker-compose.yml`:
|
|
|
|
|
|
web:
|
|
|
build: .
|
|
|
@@ -107,14 +114,18 @@ We then define a set of services using `docker-compose.yml`:
|
|
|
|
|
|
This defines two services:
|
|
|
|
|
|
- - `web`, which is built from `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/).
|
|
|
+ - `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.
|
|
|
|
|
|
-Now if we run `docker-compose up`, it'll pull a Redis image, build an image for our own code, and start everything up:
|
|
|
+### Build and run your app with Compose
|
|
|
+
|
|
|
+Now, when you run `docker-compose up`, Compose will pull a Redis image, build an
|
|
|
+image for your code, and start everything up:
|
|
|
|
|
|
$ docker-compose up
|
|
|
Pulling image redis...
|
|
|
@@ -124,11 +135,12 @@ Now if we run `docker-compose up`, it'll pull a Redis image, build an image for
|
|
|
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 (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 to
|
|
|
-`docker-compose up` and use `docker-compose ps` to see what is currently running:
|
|
|
+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
|
|
|
+is currently running:
|
|
|
|
|
|
$ docker-compose up -d
|
|
|
Starting composetest_redis_1...
|
|
|
@@ -139,19 +151,17 @@ If you want to run your services in the background, you can pass the `-d` flag t
|
|
|
composetest_redis_1 /usr/local/bin/run Up
|
|
|
composetest_web_1 /bin/sh -c python app.py Up 5000->5000/tcp
|
|
|
|
|
|
-`docker-compose run` allows you to run one-off commands for your services. For
|
|
|
-example, to see what environment variables are available to the `web` service:
|
|
|
+The `docker-compose run` command allows you to run one-off commands for your
|
|
|
+services. For example, to see what environment variables are available to the
|
|
|
+`web` service:
|
|
|
|
|
|
$ docker-compose run web env
|
|
|
|
|
|
-
|
|
|
-See `docker-compose --help` other commands that are available.
|
|
|
+See `docker-compose --help` to see other available commands.
|
|
|
|
|
|
If you started Compose with `docker-compose up -d`, you'll probably want to stop
|
|
|
your services once you've finished with them:
|
|
|
|
|
|
$ docker-compose stop
|
|
|
|
|
|
-That's more-or-less how Compose works. See the reference section below for full
|
|
|
-details on the commands, configuration file and environment variables. If you
|
|
|
-have any thoughts or suggestions, [open an issue on GitHub](https://github.com/docker/docker-compose).
|
|
|
+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.
|