AWS EB, Play Framework and Docker: Application Already running - amazon-web-services

Question

I am running a Play 2.2.3 web application on AWS Elastic Beanstalk, using SBTs ability to generate Docker images. Uploading the image from the EB administration interface usually works, but sometimes it gets into a state where I consistently get the following error:
Docker container quit unexpectedly on Thu Nov 27 10:05:37 UTC 2014:
Play server process ID is 1 This application is already running (Or
delete /opt/docker/RUNNING_PID file).
And deployment fails. I cannot get out of this by doing anything else than terminating the environment and setting it up again. How can I avoid that the environment gets into this state?

Answer 1

Sounds like you may be running into the infamous Pid 1 issue. Docker uses a new pid namespace for each container, which means first process gets PID 1. PID 1 is a special ID which should be used only by processes designed to use it. Could you try using Supervisord instead of having playframework running as the primary processes and see if that resolves your issue? Hopefully, supervisord handles Amazon's termination commands better than the play framework.

Answer 2

#dkm was having the same issue with my dockerized play app. I package my apps as standalone for production using '$ sbt clean dist` commands. This produces a .zip file that you can deploy to some folder in your docker container like /var/www/xxxx.
Get a bash shell into your container: $ docker run -it <your image name> /bin/bash
Example: docker run -it centos/myapp /bin/bash
Once the app is there you'll have to create an executable bash script I called mine startapp and the contents should be something like this:
Create the script file in the docker container:
$ touch startapp && chmod +x startapp
$ vi startapp
Add the execute command & any required configurations:
#!/bin/bash
/var/www/<your app name>/bin/<your app name> -Dhttp.port=80 -Dconfig.file=/var/www/pointflow/conf/<your app conf. file>
Save the startapp script then from a new terminal and then you must commit your changes to your container's image so it will be available from here on out:
Get the running container's current ID:
$ docker ps
Commit/Save the changes
$ docker commit <your running containerID> <your image's name>
Example: docker commit 1bce234 centos/myappsname
Now for the grand finale you can docker stop or exit out of the running container's bash. Next start the play app using the following docker command:
$ docker run -d -p 80:80 <your image's name> /bin/sh startapp
Example: docker run -d -p 80:80 centos/myapp /bin/sh startapp
Run docker ps to see if your app is running. You see something similar to this:
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
19eae9bc8371 centos/myapp:latest "/bin/sh startapp" 13 seconds ago Up 11 seconds 0.0.0.0:80->80/tcp suspicious_heisenberg
Open a browser and visit your new dockerized app
Hope this helps...