prod-server.html.md.erb

---
title: Production Server Configuration
owner: Buildpacks
---



This topic describes how to configure a production server for your apps.

When you deploy an app, Cloud Foundry determines the command used to start the app through the following process:

1. If the developer uses the command `cf push -c COMMAND`, then Cloud Foundry uses `COMMAND` to start the app.

1. If the developer creates a file called a Procfile, Cloud Foundry uses the Procfile to configure the command that launches the app.
See the <a href="#procfile">About Procfiles</a> section below for more information.

1. If the developer does not use `cf push -c COMMAND` and does not create a Procfile, then Cloud Foundry does one of the following,
depending on the buildpack:
    + Uses a default start command.
    + Fails to start the app and shows a warning that the app is missing a Procfile.

##<a id="procfile"></a>About Procfiles

One reason to use a Procfile is specify a start command for buildpacks where a default start command is not provided.
Some buildpacks, such as Python, that work on a variety of frameworks, do not attempt to provide a default start command.

Another reason to use a Procfile is to configure a production server for web apps.

A Procfile enables you to declare required runtime processes, called process types, for your web app.
Process managers in a server use the process types to run and manage the workload.
In a Procfile, you declare one process type per line and use the following syntax:

<pre class="code">
PROCESS_TYPE: COMMAND
</pre>

* `PROCESS_TYPE` is `web`. A `web` process handles HTTP traffic.
* `COMMAND` is the command line to launch the process.

For example, a Procfile with the following content starts the launch script created by the build process for a Java app:

```
web: build/install/MY-PROJECT-NAME/bin/MY-PROJECT-NAME
```

Procfile support is integrated into the the [buildpack lifecycle](https://github.com/cloudfoundry/buildpackapplifecycle).
However, due to differing behavior of buildpacks, it may not be suitable with all buildpacks. Procfiles can be used with the
following buildpacks:

* [Binary Buildpack](./binary/index.html)

* [.NET Core Buildpack](./dotnet-core/index.html)

* [Go Buildpack](./go/index.html)

* [NGINX Buildpack](./nginx/index.html)

* [Node.js Buildpack](./node/index.html)

* [Python Buildpack](./python/index.html)

* [R Buildpack](./r/index.html)

* [Ruby Buildpack](./ruby/index.html)

##<a id="specify-server"></a>Specify a Web Server

Follow these steps to specify a web server using a Procfile.
For more information about configuring a web server for Rails apps, see the [Configure a Ruby Web Server](#config-ruby) section of this topic.

1. Create a blank file with a command line for a `web` process type.

2. Save it as a file named `Procfile` with no extension in the root directory of your app.

3. Push your app.

##<a id="config-ruby"></a>Configure a Ruby Web Server

Cloud Foundry uses the default standard Ruby web server library WEBrick for Ruby and Ruby on Rails apps.
However, Cloud Foundry can support a more robust production web server, such as Phusion Passenger, Puma, Thin, or Unicorn.

To instruct Cloud Foundry to use a web server other than WEBrick, perform the following steps:

1. Add the gem for the web server to your Gemfile.

1. In the `config` directory of your app, create a new configuration file or modify an existing file.
Refer to your web server documentation for how to configure this file. The following example uses the Puma web server:

    <pre class="code">
    &#35; config/puma.rb
    threads 8,32
    workers 3

    on_worker_boot do
      # things workers do
    end
</pre>

1. In the root directory of your app, create a Procfile and add a command line for a `web` process type that points to your web server.
For information about configuring the specific command for a process type, see your web server documentation.<br/><br/>
    The following example shows a command that starts a Puma web server and specifies the app runtime environment, TCP port, and paths to the server state information and configuration files:
   
    <pre class="code">
    web: bundle exec puma -e $RAILS_ENV -p 1234 -S ~/puma -C config/puma.rb
    </pre>