Question: How do I mount an Amazon EFS volume to an application directory in an Elastic Beanstalk environment?

I want to mount an Amazon Elastic File System (Amazon EFS) volume to an application directory in an AWS Elastic Beanstalk environment.

Short descriptionThe following resolution provides general instructions for mounting an Amazon EFS volume on platforms based on Amazon Linux 1, using the PHP solution stack as an example.If you're using another solution stack, follow the same steps, but choose the correct application directory and staging directory for your solution stack from the following options:-----------------------------------------------------Solution stack             Application directory                    Staging directoryNodejs                     /var/app/current                         /tmp/deployment/applicationPHP                        /var/app/current                         /var/app/ondeckRuby (Passenger)           /var/app/current                         /var/app/ondeckRuby (Puma)                /var/app/current                         /var/app/ondeckJava with Tomcat           /usr/share/tomcat*/webapps/ROOT          /tmp/deployment/application/ROOTJava SE                    /var/app/current                         /var/app/stagingPython                     /opt/python/current/app                  /opt/python/ondeck/appGo                         /var/app/current                         /var/app/stagingSingle Container Docker    /var/app/current                         /var/app/stagingMulti-Container Docker     /var/app/current                         /var/app/staging-----------------------------------------------------Important: You can't mount an Amazon EFS volume directly to the application directory because the contents of /var/app/current are moved to /var/app/current.old whenever you deploy an Elastic Beanstalk application. The current deployed source bundle is moved to the application directory. If you mount the Amazon EFS volume to /var/app/current, then that volume is moved to /var/app/current.old after the deployment is completed. For example, see the following eb-activity.log output:===============================[2020-02-12T02:28:18.237Z] INFO  [3159]  - [Application deployment Sample Application@1/StartupStage1/AppDeployEnactHook/01_flip.sh] : Starting activity...[2020-02-12T02:28:18.431Z] INFO  [3159]  - [Application deployment Sample Application@1/StartupStage1/AppDeployEnactHook/01_flip.sh] : Completed activity. Result:  ++ /opt/elasticbeanstalk/bin/get-config container -k app_staging_dir  + EB_APP_STAGING_DIR=/var/app/ondeck  ++ /opt/elasticbeanstalk/bin/get-config container -k app_deploy_dir  + EB_APP_DEPLOY_DIR=/var/app/current  + '[' -d /var/app/current ']'  + mv /var/app/current /var/app/current.old  + mv /var/app/ondeck /var/app/current  + nohup rm -rf /var/app/current.old===============================Resolution1.    Confirm that your source bundle is unzipped in the staging directory. See the following example eb-activity.log output:===============================[2020-02-12T02:28:16.336Z] INFO  [3159]  - [Application deployment Sample Application@1/StartupStage0/AppDeployPreHook/01_unzip.sh] : Starting activity...[2020-02-12T02:28:16.631Z] INFO  [3159]  - [Application deployment Sample Application@1/StartupStage0/AppDeployPreHook/01_unzip.sh] : Completed activity. Result:  ++ /opt/elasticbeanstalk/bin/get-config container -k app_user  + EB_APP_USER=webapp  ++ /opt/elasticbeanstalk/bin/get-config container -k app_staging_dir  + EB_APP_STAGING_DIR=/var/app/ondeck  ++ /opt/elasticbeanstalk/bin/get-config container -k source_bundle  + EB_SOURCE_BUNDLE=/opt/elasticbeanstalk/deploy/appsource/source_bundle  + rm -rf /var/app/ondeck  + /usr/bin/unzip -d /var/app/ondeck /opt/elasticbeanstalk/deploy/appsource/source_bundle  Archive:  /opt/elasticbeanstalk/deploy/appsource/source_bundle     creating: /var/app/ondeck/.ebextensions/    inflating: /var/app/ondeck/.ebextensions/logging.config      inflating: /var/app/ondeck/scheduled.php      inflating: /var/app/ondeck/index.php      inflating: /var/app/ondeck/cron.yaml      inflating: /var/app/ondeck/styles.css     extracting: /var/app/ondeck/logo_aws_reduced.gif    + chown -R webapp:webapp /var/app/ondeck  + chmod 775 /var/app/ondeck===============================Note: All the appdeploy pre hooks in /opt/elasticbeanstalk/hooks/appdeploy/pre/ and .ebextensions are run in the staging directory.2.    Create a .ebextensions folder in the root directory of the source bundle.3.    To mount an Amazon EFS volume to a specific directory (for example, /efs), add a formatted configuration file (YAML or JSON) to your directory.4.    To mount your Amazon EFS volume to an application directory, you must create a symlink to the staging directory. To create a symlink from /efs that points to the staging directory, use container_commands to create a .config file in your .ebextensions folder. For example:container_commands:  01_symlink:    command: ln -s /efs /var/app/ondeck/Note: When appdeploy enact hooks are run during a deployment in an Elastic Beanstalk environment, the contents of the staging directory are moved to the application directory. For example, in a PHP solution, the flip.sh script moves the contents of the staging directory to the application directory. The flip.sh script is the first script of AppDeployEnactHook in /opt/elasticbeanstalk/hooks/appdeploy/enact/.