Proper way to showcase multi-container web app to customers
You mention that you are demonstrating this for a customer. The first question you should ask yourself (or, more pertinently, the customer) is :


  what does this customer really want?


Why have they come to you for this work? What is the pain they are currently feeling, what value are you providing to them.

Then, compare and contrast - show them the delta that your solution brings to them.


It may be for example that they want to maintain a legacy application, but upgrade the hardware or underlying components ? In that case, show them how you have contained them with no negative experience to their users.
It may be that they need to scale the capacity for usage of their application   - they want to be able to meet demand elastically. Show them how by deploying in a container setup, you can scale out.
It may be that they need four nines reliability - show them that you can have an easier HA setup - knock out one of the instances and prove that the application still works.
It may be that they want faster delivery with no little impact on quality. Show that your delivery pipeline works smoothly with some automated tests and QA, with delivery and deployment.


TL;DR : Find out what your customer wants. Demonstrate the existing way of doing things. Compare it with the "new" way, and highlight the delta.