Thanks for taking the time to read my post and provide feedbacks! Really appreciated. You are right regarding the immutability part. I will clarify my post. I will be honest however, I have never felt 100% comfortable running multiple docker containers in one instance simply because it becomes much harder to profile, to manage security and to limit the blast radius — but you are right, you can still achieve immutability that way.
Thanks for the Cloud Custodian link. I have followed CapitalOne projects for a while, and I have really liked them.
Thanks once more :)