Extending php.ini in your Elastic Beanstalk configuration

Use a configuration file with a files block to add a .ini file to /etc/php.d/ on the instances in your environment. The main configuration file, php.ini, pulls in settings from files in this folder in alphabetical order. Many extensions are enabled by default by files in this folder.

Example .ebextensions/mongo.config

files:
  "/etc/php.d/99mongo.ini":
    mode: "000755"
    owner: root
    group: root
    content: |
      extension=mongo.so