Clarify Plans For EC2 Tickets Given ECS GA

[original-brownbear]

@yegor256 I need some clarification on the product you want here :)

What I'd like to get out of this ticket is:

• Clarification of whether or not dynamically provisioning EC2 instances is a requirement still given that ECS is out.
• If it's not a requirement anymore and those tickets can be closed, clarification on whether or not ECS can be made a requirement instead.

Background

Currently I see the following open issues waiting to be implemented:
#755
#824
#825
#826
#827

They all revolve around implementing functionality that will allow on-demand provisioning of EC2 instances, that Rultor can then SSH into.
Given that:

1. I in Expose Docker API over HTTPS #1020 hopefully clarified the weakness of the SSH/Bash architecture currently used and Rultor should be moved towards the Docker REST API
2. Those tickets are very old ( opened Jan-April 2015 ) and Amazon released ECS meanwhile, offering what is to be implemented here out of the box seemingly

.... I think, based on the information in the currently open issues, the above tickets should be closed and substituted with a a set of tickets implementing ECS use instead since:

• Dynamically setting up docker Daemons on EC2 would simply be reinventing ECS
• Implementing ECS would require significantly less effort than dynamically setting up EC2 instances
  • In addition to the eventually pretty much mandatory move to the Docker REST API this would only require implementing the ECS interaction
  • ECS task definitions already provide exactly what would have to be implemented in the above tasks (setting up and tearing down of the container etc.).
• Also we'd get rid of trivial maintenance issues like Rultor can't pull the image, 'pid' file is absent #1009, constantly causing downtime

=> I think implementing what above tickets suggest would require a lot more resources and leave us with a way less stable result compared to implementing ECS instead.

Let me know what to plan for here @yegor256 :)

[original-brownbear]

@alex-palevsky assign @yegor256 please :)