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I have deployed my PHP application in amazon EC2 using elastic beanstalk instance. The filesystem structure of my app looks like this:

MyApp
 |-css
 |  |-...
 |-js
 |  |-...
 |-uploads
 |  |- image.png
 |  |- file.pdf
 |  |- ...
 |-index.php
 |-...

My app allows users to upload images. Its a simple application to web-manage some files and is currently only used by my client. So when files are uploaded I am placing them under uploads folder as shown above. Problem is my files don't last in this folder for long. After a day or two,I ssh and find the uploads folder is empty. I am not sure what happens but I suspect elastic beanstalk does create a new instance and consequently overwrites the uploads folder contents.

How do I fix this situation?

Thanks.

Andrey Belykh
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nmvictor
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1 Answers1

6

Applications deployed on Elastic Beanstalk should be stateless. I.e. They should not store state on the EC2 instances, such as a file or a in memory http session.

AWS Elastic Beanstalk uses autoscaling behind the scene to add or remove instances from your pool, depending on your application workload.

When you change AWS Elastic Beanstalk configuration, it also might replace instances with new one.

Best practice is to store your application state in a shared store, available to all your instances.

Amazon S3 is a very good candidate for this, you just need to slightly modify your application to let users browser securely upload the files to S3.

Look at the answer to this question for more details. Amazon S3 direct file upload from client browser - private key disclosure

You can also implement client side upload without using a form, by directly using Amazon Javascript's SDK in the browser.

Community
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Sébastien Stormacq
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  • Thanks so much for the insight. What happens to how the files are accessed? Currently user has to access via http://myapp.elasticbeanstalk.com/myapp/uploads/file.pdf. How will I link the S3 files to be accessible via the same URL? – nmvictor Jan 23 '15 at 11:56
  • @MyApplynx You create a php controller for that url that forwards them to the s3 location. – Nick Humrich Jan 23 '15 at 17:59
  • Your controller can build web pages with links to S3 instead of links to your app. Your controller can use S3 signed URLs to ensure only valid users will access S3 – Sébastien Stormacq Jan 24 '15 at 06:34