mirror of
https://github.com/moby/moby.git
synced 2022-11-09 12:21:53 -05:00
204 lines
6 KiB
Markdown
204 lines
6 KiB
Markdown
page_title: Running a Node.js app on CentOS
|
||
page_description: Installing and running a Node.js app on CentOS
|
||
page_keywords: docker, example, package installation, node, centos
|
||
|
||
# Node.js Web App
|
||
|
||
> **Note**:
|
||
>
|
||
> - This example assumes you have Docker running in daemon mode. For
|
||
> more information please see [*Check your Docker
|
||
> install*](../hello_world/#running-examples).
|
||
> - **If you don’t like sudo** then see [*Giving non-root
|
||
> access*](../../installation/binaries/#dockergroup)
|
||
|
||
The goal of this example is to show you how you can build your own
|
||
Docker images from a parent image using a `Dockerfile`
|
||
. We will do that by making a simple Node.js hello world web
|
||
application running on CentOS. You can get the full source code at
|
||
[https://github.com/gasi/docker-node-hello](https://github.com/gasi/docker-node-hello).
|
||
|
||
## Create Node.js app
|
||
|
||
First, create a directory `src` where all the files
|
||
would live. Then create a `package.json` file that
|
||
describes your app and its dependencies:
|
||
|
||
{
|
||
"name": "docker-centos-hello",
|
||
"private": true,
|
||
"version": "0.0.1",
|
||
"description": "Node.js Hello World app on CentOS using docker",
|
||
"author": "Daniel Gasienica <daniel@gasienica.ch>",
|
||
"dependencies": {
|
||
"express": "3.2.4"
|
||
}
|
||
}
|
||
|
||
Then, create an `index.js` file that defines a web
|
||
app using the [Express.js](http://expressjs.com/) framework:
|
||
|
||
var express = require('express');
|
||
|
||
// Constants
|
||
var PORT = 8080;
|
||
|
||
// App
|
||
var app = express();
|
||
app.get('/', function (req, res) {
|
||
res.send('Hello World\n');
|
||
});
|
||
|
||
app.listen(PORT);
|
||
console.log('Running on http://localhost:' + PORT);
|
||
|
||
In the next steps, we’ll look at how you can run this app inside a
|
||
CentOS container using Docker. First, you’ll need to build a Docker
|
||
image of your app.
|
||
|
||
## Creating a `Dockerfile`
|
||
|
||
Create an empty file called `Dockerfile`:
|
||
|
||
touch Dockerfile
|
||
|
||
Open the `Dockerfile` in your favorite text editor
|
||
and add the following line that defines the version of Docker the image
|
||
requires to build (this example uses Docker 0.3.4):
|
||
|
||
# DOCKER-VERSION 0.3.4
|
||
|
||
Next, define the parent image you want to use to build your own image on
|
||
top of. Here, we’ll use [CentOS](https://index.docker.io/_/centos/)
|
||
(tag: `6.4`) available on the [Docker
|
||
index](https://index.docker.io/):
|
||
|
||
FROM centos:6.4
|
||
|
||
Since we’re building a Node.js app, you’ll have to install Node.js as
|
||
well as npm on your CentOS image. Node.js is required to run your app
|
||
and npm to install your app’s dependencies defined in
|
||
`package.json`. To install the right package for
|
||
CentOS, we’ll use the instructions from the [Node.js
|
||
wiki](https://github.com/joyent/node/wiki/Installing-Node.js-via-package-manager#rhelcentosscientific-linux-6):
|
||
|
||
# Enable EPEL for Node.js
|
||
RUN rpm -Uvh http://download.fedoraproject.org/pub/epel/6/i386/epel-release-6-8.noarch.rpm
|
||
# Install Node.js and npm
|
||
RUN yum install -y npm
|
||
|
||
To bundle your app’s source code inside the Docker image, use the
|
||
`ADD` instruction:
|
||
|
||
# Bundle app source
|
||
ADD . /src
|
||
|
||
Install your app dependencies using the `npm`
|
||
binary:
|
||
|
||
# Install app dependencies
|
||
RUN cd /src; npm install
|
||
|
||
Your app binds to port `8080` so you’ll use the
|
||
`EXPOSE` instruction to have it mapped by the
|
||
`docker` daemon:
|
||
|
||
EXPOSE 8080
|
||
|
||
Last but not least, define the command to run your app using
|
||
`CMD` which defines your runtime, i.e.
|
||
`node`, and the path to our app, i.e.
|
||
`src/index.js` (see the step where we added the
|
||
source to the container):
|
||
|
||
CMD ["node", "/src/index.js"]
|
||
|
||
Your `Dockerfile` should now look like this:
|
||
|
||
# DOCKER-VERSION 0.3.4
|
||
FROM centos:6.4
|
||
|
||
# Enable EPEL for Node.js
|
||
RUN rpm -Uvh http://download.fedoraproject.org/pub/epel/6/i386/epel-release-6-8.noarch.rpm
|
||
# Install Node.js and npm
|
||
RUN yum install -y npm
|
||
|
||
# Bundle app source
|
||
ADD . /src
|
||
# Install app dependencies
|
||
RUN cd /src; npm install
|
||
|
||
EXPOSE 8080
|
||
CMD ["node", "/src/index.js"]
|
||
|
||
## Building your image
|
||
|
||
Go to the directory that has your `Dockerfile` and
|
||
run the following command to build a Docker image. The `-t`
|
||
flag let’s you tag your image so it’s easier to find later
|
||
using the `docker images` command:
|
||
|
||
sudo docker build -t <your username>/centos-node-hello .
|
||
|
||
Your image will now be listed by Docker:
|
||
|
||
sudo docker images
|
||
|
||
> # Example
|
||
> REPOSITORY TAG ID CREATED
|
||
> centos 6.4 539c0211cd76 8 weeks ago
|
||
> gasi/centos-node-hello latest d64d3505b0d2 2 hours ago
|
||
|
||
## Run the image
|
||
|
||
Running your image with `-d` runs the container in
|
||
detached mode, leaving the container running in the background. The
|
||
`-p` flag redirects a public port to a private port
|
||
in the container. Run the image you previously built:
|
||
|
||
sudo docker run -p 49160:8080 -d <your username>/centos-node-hello
|
||
|
||
Print the output of your app:
|
||
|
||
# Get container ID
|
||
sudo docker ps
|
||
|
||
# Print app output
|
||
sudo docker logs <container id>
|
||
|
||
> # Example
|
||
> Running on http://localhost:8080
|
||
|
||
## Test
|
||
|
||
To test your app, get the the port of your app that Docker mapped:
|
||
|
||
sudo docker ps
|
||
|
||
> # Example
|
||
> ID IMAGE COMMAND ... PORTS
|
||
> ecce33b30ebf gasi/centos-node-hello:latest node /src/index.js 49160->8080
|
||
|
||
In the example above, Docker mapped the `8080` port
|
||
of the container to `49160`.
|
||
|
||
Now you can call your app using `curl` (install if
|
||
needed via: `sudo apt-get install curl`):
|
||
|
||
curl -i localhost:49160
|
||
|
||
> HTTP/1.1 200 OK
|
||
> X-Powered-By: Express
|
||
> Content-Type: text/html; charset=utf-8
|
||
> Content-Length: 12
|
||
> Date: Sun, 02 Jun 2013 03:53:22 GMT
|
||
> Connection: keep-alive
|
||
>
|
||
> Hello World
|
||
|
||
We hope this tutorial helped you get up and running with Node.js and
|
||
CentOS on Docker. You can get the full source code at
|
||
[https://github.com/gasi/docker-node-hello](https://github.com/gasi/docker-node-hello).
|
||
|
||
Continue to [*Redis
|
||
Service*](../running_redis_service/#running-redis-service).
|