prod-server.html.md.erb

---
title: Configuring the production server for Cloud Foundry apps
owner: Buildpacks
---

You can configure a production server for your apps in Cloud Foundry.

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

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

1. If you create a file called a Procfile, Cloud Foundry uses Procfile to configure the command that launches the app.
See <a href="#procfile">About Procfiles</a>.

1. If you do not use `cf push -c COMMAND` and do 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>Procfiles

Use a Procfile to specify a start command for buildpacks when a default start command is not provided.
Some buildpacks use Python to work on a variety of frameworks and do not attempt to provide a default start command.

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

When you use a Procfile, you declare required runtime processes, and called process types, for your web app.
Process managers in a server use the process type to run and manage the workload.

In a Procfile, you declare one process type per line and use the following syntax:

<pre class="terminal">
PROCESS-TYPE: COMMAND
</pre>

Where:

* `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:

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

Procfile support is integrated into the [buildpack lifecycle](https://github.com/cloudfoundry/buildpackapplifecycle).
However, due to differing behavior of buildpacks, it might 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>Specifying 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 [Configuring a Ruby web server](#config-ruby).

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>Configuring 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. For example, Phusion Passenger, Puma, Thin, or Unicorn.

To instruct Cloud Foundry to use a web server other than WEBrick, use 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.
See your web server documentation for how to configure this file.

    The following example uses the Puma web server:

    <pre class="terminal">
        &#35; config/puma.rb
        threads 8,32
        workers 3
        <br>
        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, paths to the server state information, and configuration files:

    <pre class="terminal">
    web: bundle exec puma -e $RAILS_ENV -p 1234 -S ~/puma -C config/puma.rb
    </pre>