Jenkins BlueOcean, Jenkinsfile, docker builds & autoscaled agent pool?

[ringo....@ontoforce.com]

Hello,

I have been away from the Jenkins community for about 4 years now. Everything moved on, so I'm a bit lost at the moment. For the past 2 hours, I have tried to find the right set of plugins & configuration to become the following setup:

* I host a Jenkins master on a fixed machine on AWS, within a VPC and behind an ALB.

* I want to use Jenkins BlueOcean with Jenkinsfile pipeline dsl

* I want to run builds in Docker containers, based on the Docker image config from the `agent` section of my Jenkinsfile

* I want these Docker containers to be spread on an autoscaled EC2 instance group or in an ECS cluster. When no builds run, I want no slave VMs to be active. Spot pricing is not directly needed given AWS VMs are now billed by the second.

What I found so far regarding the master:

* Install a master 

* add blueocean plugin

* add pipeline plugin & dependencies.

What I did not find regarding the autoscaling of slaves:

* https://plugins.jenkins.io/scalable-amazon-ecs: I guess this plugin is no longer maintained. If so, can this be removed from the portal?

* https://plugins.jenkins.io/amazon-ecs: this plugin can be backed by an autoscaling group, but the docker templates must be configured upfront. As far as I can read, it doesn't pick up the info from the Jenkinsfile.

* https://plugins.jenkins.io/amazon-ecs: does this plugin support autoscaling? If a Docker based build is needed, will it dispatch it to such an EC2 machine running the jenkins-slave software & Docker? Can I control the number of concurrent Docker runs on such a machine?

Looking forward to your experiences and remarks.

Any additional info or tools on how to set this up scripted (read: Terraform/Chef) is also welcome.

Ringo