Matt, you pose a couple of really good questions, each of which might be a long topic on its own right...
Before I get too deep on answering your questions, I should note that VMWare is focused on managing virtual machines and Docker is about containers. They're similar, but not the same. Docker lets you provision multiple copies of apps or multiple apps on a single host, but that host can be a physical machine or a virtual machine.
VMWare is probably more similar to the Vagrant / Virtual Box combination than Docker. You can find a pretty good discussion of this topic over at StackOverlow.
Also, Docker Containers are configured via Docker Files - basically just text files specifying the options you want configured. You can edit them from any text editor and there's a LOT of ready to use avialable online @ Docker Hub.
You may find that you don't really need a GUI if you're using pre-built configs or perhaps just taking an existing DockerFile and modifying it for your particular use.
Now, to address your specific questons....
GUI / Docker Management
- We mostly use Docker for local development environments so GUI Management isn't a high priority for those cases. I have tried out the Open Source Panamax product and it works well for my development needs. It is designed to manage both production and development environments so it may be a good (and free) option to replace your vCenter setups. It has pretty slick UI's & Monitoring / Charts though I'm not sure how it compares to your current VMWare Environrment.
- Another Open Source Option - Ship Yard - I haven't used this option myself, but it's got a pretty strong GitHub history and appears to have a strong base of community supporters.
- Commercial Option : Stack Engine - This is one of the leading "Enterprise" Docker Management solutions. it may be a bit more complex than you need, depending on the size of your IT / Development organizations.
Backup Solutions
When you're running a Docker infrastructure, you're going to be managing the Host System (potentially a VM or Physical Server). Typically, you'll already be using some sort of Backup Solution at this level. You may want to seperate the backup of your Host / VM level from the backup of your Docker Containers and whatever applications and data they contain.
Docker Images are the basis of the containers you run. In addition, containers can use Data Volumes which are independant to the container itself. The Docker team provides a utility for backup and restoration of Data Volumes on GitHub.
For a commercially supported sytem for backup management of Docker Containers, you may want to consider Asigra's Solution. It may be more targeted towards business with larger IT & Development organiztions than your current needs.
Magento & Docker
For the most part, you're correct in assuming that Docker is agnostic to the applicaitons you're running in its containers. I've used Docker to create a Magento Developer Environment that closely matches our Amazon Web Services production systems by configuring Apache, Zend Server, MySQL, Varnish, Memcached as seperate containers even with multiple instances for load balancing at the web & db layers. It's a great way to test if your code is going to work in the cloud without having to incur the costs of testing it on the live environments.
That being said, I've recently been doing some research on Magento focused Docker considerations and I've shared my bookmarks online in my Evernote Notebook : Magento & Docker
Hope this helped!
