What is the difference between Docker and VirtualBox?

Question

I have used VirtualBox a lot on my Mac for Linux images. What would be the advantage of moving to Docker? So I would like to know what the difference between Docker and VirtualBox is?

Solution

Docker is an application virtualisation tool. VirtualBox is a Virtual Machine tool.

VB simulates an entire hardware environment whereas Docker isolates the reads/writes of the enclosed application from the rest of the OS.

The overheads of a whole VM can be considerable whereas Docker apps don't need to replicate all of the OS so, in theory, you may be able to get more out of your host environment.

On the other hand, it can be very tricky to get applications to play nicely together with Docker due to the application isolation.

Also, Docker does not yet run on Windows (that is due soon though) so there are platform limitations too.

Comments

[Daniel B]

Docker can also use full virtualization. Depends on the engine.

[Julian Knight]

Can you explain please? Which engine gives a full VM with Docker?

[Daniel B]

Driver was the correct word. Anyway, take a look. I though it would’ve progressed further by now, though.

[Julian Knight]

Hmm, perhaps you over stated then? In truth you could say that it may support it in the future, it doesn't support it now.

[heavyd]

@DanielB, the GitHub repo you linked to is to the Docker Machine project, which is different from Docker the container technology. Machine is a tool for managing VMs where Docker containers would be run.