First of all with setting up the Docker images the micro-services became flexible and scalable. About the Symfony development part we take a steps to cover functionality with Unit tests, then we focused on feature development in Scrum way. As we had an on-demand remote web development team and DevOps engineer provided, we done infrastructure migration and bugfix in parallel. When CI was ready first and first launches to stage server were OK, CI was applied to the prod machines.
So far we have: Deploy in one click, time to prod reduced, code quality and quality assurance up with the CI that runs unit tests and code analyzator before deploying, costs to maintain reduced to 30% with the new clever infrastructure.