stagecoach: host multiple Node apps on your Linux servers
Stagecoach is a framework for deploying node.js web applications and testing them on a staging server, then deploying them to production servers. It includes a complete mechanism for running many such node applications on a single staging or production server, restarting them gracefully on reboot, and accessing them at nice URLs without port numbers.
Stagecoach also includes
sc-deploy, a minimalist deployment tool based on rsync that understands multiple deployment targets and makes pretty much no assumptions about your project. It is suitable for pretty much any site or web app you wish to deploy, although the examples provided are node-oriented. Although
sc-deploy relies on
rsync it will also run an optional
dependencies script to install dependencies that are server-specific and can't be transferred from your development environment. This is handy for installing npm modules with
We also threw in a nice installer script for node, forever and mongodb on Ubuntu which installs the recommended versions from Joyent and the MongoDB team.
sc-proxy is a node.js-based frontend proxy server solution for web apps that listen on independent ports, built on top of the amazing node-http-proxy by nodejitsu. It's great for testing lots of node projects on the same staging server while giving them all reasonable hostnames and allowing them to respond on port 80. With a little tweaking it may also be suitable for production deployment of clusters of small sites that don't need a VPS unto themselves.
We chose to create these tools because we wanted a solution that didn't contain a lot of implicit assumptions about the sites being deployed (such as Capistrano, which really wants to deploy a Rails project, although you can convince it to deploy other things). If you know how to add a command to a shell script, then you know how to change the behavior of stagecoach.
The provided start and stop scripts require that
forever be installed globally:
npm install -g forever
forever is a great node utility for ensuring that a process is restarted if it should fail.
sc-deploy doesn't care where you install things, for easiest use of
sc-proxy Stagecoach should be installed to
/opt/stagecoach. Apps will run from
/opt/stagecoach/apps/appname/current. If that is not an option for you, you'll need to make modifications.
Copy stagecoach to
/opt/stagecoach on your staging server. Copy
/opt/stagecoach/settings and make sure
USER is set to the non-root user that your apps should run as. Then create the
/opt/stagecoach/apps folder and
chown that folder to the same non-root user.
nodeapps is a nice name if you want to make a new user for node apps, but any user account can be used. Root is a bad choice for security reasons.
Additional configuration steps are covered under
sc-deploy is a short bash script that handles web app deployment with automatic rollback on failure. You'll find it in
Like other deployment tools, sc-deploy deploys to a new folder on the target server each time you deploy, and switches a symlink at the last possible minute only if everything went smoothly. The server is stopped, migrated and started only after the rsync is complete. So depending on how long your database migrations take, your deployment downtime can be very short indeed.
sc-deploy creates a symbolic link from
/opt/stagecoach/apps/example/current to the latest deployment folder if everything happens successfully (assuming that your project is called
myproject and you base your paths on those in
example). If you're deploying traditional web languages like PHP, you'll want to make sure your web document root is configured accordingly.
sc-deploy relies on bash scripts in a subdirectory of your project called
deployment to carry out the work of starting (
start), installing dependencies for (
dependencies), stopping (
stop) and migrating (
migrate) your project. If any of these scripts exit with a nonzero status, the deployment process stops and the previous version of the site stays live. Currently any failed deployment folders are left on the server for your debugging convenience.
Settings that apply to all deployment targets for this project, such as the project's name and (usually) the deployment directory, reside in
deployment/settings. You'll want to edit the
PROJECT setting, and possibly the
DIR setting as well. The project name should be a reasonable Unix shortname; it's the folder name you'll be deploying to. If you use
sc-proxy it is also the subdomain you'll use to access the staging site.
Settings for a specific target, such as
staging, go in
HOST settings (for ssh and rsync) typically appear here because they are different for each server.
Most apps have folders that contain data rather than code and should not be replaced in a deployment. Check out the provided
migrate script to see how we provide a shared
data folder. A symlink to this folder is created from each new deployment folder.
rsync_exclude.txt file is present in
deployment, files mentioned there are not included in the deployment and are left alone if they exist on the server (see the
Run sc-deploy like this (after setting up your deployment folder correctly):
You'll want to make sure
sc-deploy is in your
sc-deploy deploys straightforwardly from the current directory to the target via rsync. This is a deliberate choice: the code you just QA'd on the box in front of you is the code you want to deploy, not something that might be juuuust a little different in fun and surprising ways. However you can easily wrap
sc-deploy in a script that updates from git, svn or whatever yoou may prefer and then runs tests before agreeing to carry out a deployment. As long as you have a test script that returns a nonzero exit code on failure, that can be as simple as:
git pull && ./tests && sc-deploy staging
sc-deploy plays well with jenkins and other shells for running deployment and testing tools.
Tip: you should definitely set up a trusted ssh public key that allows you to ssh to your server without entering your password over and over.
example folder you'll find an example of ndoe app deployment, with all the important bits already set up (be sure to look in
start script integrates with
sc-proxy by registering a port number for the project to listen on via the data/port file, and the provided example node app consults that file as well at startup.
Installing dependencies on the server side
Note that if your project has a
production/dependencies script it will be run immediately after the rsync is complete and before the site is restarted. This is the right place to execute
npm install if your application has dependencies on npm modules that involve compiled code that can't be transferred from your own computer.
Did your eyes skip right over all that? Don't worry - if you are copying your app's
deployment folder from the latest
example app included with stagecoach, then
npm install will happen for you automatically. Those of you already using stagecoach who want this feature can just copy
Thanks to Howard Tyson for pointing out the need to install dependencies on the server side.
You can do production hosting with
sc-proxy as well.
Just create a
data/hosts file for each site. In that site, list the hostnames that the site should respond for, like this:
myexample.com www.myexample.com some-alternate-name.com
Note that if
sc-proxy will stop responding on the staging subdomain for that site. Which doesn't bother you, because you have separate staging and production servers... I hope!
If you add or remove an app entirely, sc-proxy should spot that right away.
If you add or modify a
hosts file, there will be a delay of up to a minute. I'm working on changing this by watching these files in the filesystem in an efficient way.
Warnings and Limitations
sc-deploy expects that you will not have spaces in your target deployment folder name or your project name. If you like making things difficult for shell scripts, this is not the tool for you.
The provided sample
stop scripts do not attempt to use
chroot jails to prevent apps from seeing each other's files. If you need that, you might be happier with
This isn't for Windows.
sc-proxy is a simple reverse proxy server for web applications that are installed like
example: in subdirectories of /opt/stagecoach/apps, with a
data/port file that records the port number each web application is listening on.
sc-proxy accepts requests at nice URLs like
http://projectname.mydomain.com and proxies them to
http://localhost:3001 and so forth, so that all of the projects can respond to reasonable URLs without wacky port numbers.
node-http-proxy, which is terrific because it handles websockets and all those other neat things that node apps do, but is also a perfectly valid proxy for any plain vanilla HTTP web application.
The most convenient way to use
sc-proxy is to set up a wildcard DNS "A" record for the domain you use to stage your projects. This way you don't need to add a separate "A" record for every project that is ready to test on the staging server. In our office we have a domain name set aside for this purpose.
sc-proxy looks at the name of each folder in
/opt/stagecoach/apps and proxies traffic for that subdomain to the port specified in the
data/port file in that folder. If you have a folder called
/var/webapps/myproject that contains a
data/port file containing the number 3001, then traffic coming to
http://myproject.mydomain.com will be proxied to
http://localhost:3001. Note that in the
start script provided with
example you can find simple shell script logic to assign a currently unclaimed port number to a new web app on its first deployment.
sc-proxy is asked to access a site that isn't part of its current configuration, it will check whether that site has been added to
/var/webapps. In addition, once a minute
sc-proxy scans for any modifications to
/var/webapps, on the off chance a site has been removed or reconfigured.
sc-proxy, copy the file
config.js and change the
domain setting to match your needs. Also set
ip to the IP address you want to listen on; you can set
0.0.0.0 to respond on all interfaces. If you want to listen on a specific IP address to avoid a conflict with a second IP address reserved for Apache, you can do that as well. You can also change the port from port 80 for testing purposes, although there is not much point in using
sc-proxy if you don't plan to eventually configure it to bind on port 80.
Similarly, if Apache is on the same server, you will need to configure Apache to listen on a different IP address, or a different port if you use the
defaultPort setting of
You can set
defaultPort to forward traffic to that port if it does not match any of your Stagecoach sites. This allows sc-proxy to act as a front end to Apache, as long as you change Apache's configuration to bind on the port indicated by
defaultPort. This is one way to avoid a second IP address.
When your configuration is complete, cd to the
sc-proxy folder and run:
sc-proxy folder also contains an
upstart script that can start and stop the proxy and the associated apps on an Ubuntu system. By copying this script to
/etc/init on your Ubuntu system you can arrange for your proxy and web apps to be running at all times. You can also
start stagecoach and
stop stagecoach at any time (as root).
Installing Node and MongoDB on Ubuntu
You don't have to use Ubuntu. But if you do, you might find this shell script handy:
This shell script is provided in the
sc-proxy folder. It does what it says: it installs Node and MongoDB correctly on Ubuntu, using the recommended repositories for the latest stable releases, not the older stuff in Ubuntu's official repositories. It also configures MongoDB to run safely, accepting connections only on localhost. You can change that if you like, just please consider the security implications. MongoDB's default configuration has no security of any kind, so our changes make sense.