One of the common misconception about containers is that they act as light VMs. Which would make you think they are perfectly isolated. It’s not true. While they all give you some level of isolation, they all share a common kernel. And that is the main idea actually. Containers are lightweight because you don’t have to emulate the whole thing, because they share a common kernel.
Running your containers in production on some cloud provider might put you in a situation where your container will share a kernel with some unknown container. Does this make you uncomfortable?
VP DevRel @ Clever Cloud. I am also a nerdy metal head living in Paris. Formerly Couchbase, Nuxeo.