Configuring the application process with a Procfile - AWS Elastic Beanstalk

Configuring the application process with a Procfile

If you have more than one JAR file in the root of your application source bundle, you must include a Procfile file that tells Elastic Beanstalk which JAR(s) to run. You can also include a Procfile file for a single JAR application to configure the Java virtual machine (JVM) that runs your application.

We recommend that you always provide a Procfile in the source bundle alongside your application. This way you precisely control which processes Elastic Beanstalk runs for your application and which arguments these processes receive.

For details about writing and using a Procfile see Buildfile and Procfile.

Example Procfile
web: java -Xms256m -jar server.jar 
cache: java -jar mycache.jar
web_foo: java -jar other.jar

The command that runs the main JAR in your application must be called web, and it must be the first command listed in your Procfile. The nginx server forwards all HTTP requests that it receives from your environment's load balancer to this application.

Elastic Beanstalk assumes that all entries in the Procfile should run at all times and automatically restarts any application defined in the Procfile that terminates. To run commands that will terminate and should not be restarted, use a Buildfile.

If your Elastic Beanstalk Java SE environment uses an Amazon Linux AMI platform version (preceding Amazon Linux 2), read the additional information in this section.

Notes

  • The information in this topic only applies to platform branches based on Amazon Linux AMI (AL1). AL2023/AL2 platform branches are incompatible with previous Amazon Linux AMI (AL1) platform versions and require different configuration settings.

  • On July 18,2022, Elastic Beanstalk set the status of all platform branches based on Amazon Linux AMI (AL1) to retired. For more information about migrating to a current and fully supported Amazon Linux 2023 platform branch, see Migrating your Elastic Beanstalk Linux application to Amazon Linux 2023 or Amazon Linux 2.

By default, Elastic Beanstalk configures the nginx proxy to forward requests to your application on port 5000. You can override the default port by setting the PORT environment property to the port on which your main application listens.

If you use a Procfile to run multiple applications, Elastic Beanstalk on Amazon Linux AMI platform versions expects each additional application to listen on a port 100 higher than the previous one. Elastic Beanstalk sets the PORT variable accessible from within each application to the port that it expects the application to run on. You can access this variable within your application code by calling System.getenv("PORT").

In the preceding Procfile example, the web application listens on port 5000, cache listens on port 5100, and web_foo listens on port 5200. web configures its listening port by reading the PORT variable, and adds 100 to that number to determine which port cache is listening on so that it can send it requests.