Docker is disruptive, but at the end of the day you need somewhere to deploy it. And if you are sensible you want would to do it in the cloud, even if you are a bank.
It took me 2 days to get the initial infrastructure migrated. Then a slight bumpy road to setup some of the more advanced features such as SSL, Virtual Hosts and Zero Downtime Deployment. A typical Docker Cloud infrastructure orchestrated by Tutum sitting in AWS would look something like this: