Container Security

Chapter 1. Container Security Threats

In the last few years, the use of containers has exploded. The concepts around containers existed for several years before Docker, but most observers agree that it was Docker’s easy-to-use command-line tools that started to popularize containers among the developer community from its launch in 2013.

Containers bring many advantages: as described in Docker’s original tagline, they allow you to “build once, run anywhere.” They do this by bundling together an application and all its dependencies and isolating the application from the rest of the machine it’s running on. The containerized application has everything it needs, and it is easy to package up as a container image that will run the same on my laptop and yours, or in a server in a data center.

A knock-on effect of this isolation is that you can run multiple different containers side by side without them interfering with each other. Before containers, you could easily end up with a dependency nightmare where two applications required different versions of the same packages. The easiest solution to this problem was simply to run the applications on separate machines. With containers, the dependencies are isolated from each other so it becomes straightforward to run multiple apps on the same server. People quickly realized that they could take advantage of containerization to run multiple applications on the same host (whether it’s a virtual machine or a bare-metal server) without having ...