Containerized Twelve-Factor Apps

Although the Twelve-Factor App methodology is older than the current trend toward containerization using Docker and related tools, it's very aligned. Both tools are oriented toward scalable services in the cloud, and containers help to create patterns that match the ones described in the Twelve-Factor methodology.

We will talk more about Docker containers in Chapter 8, Advanced Event-Driven Structures.

The most important, arguably, is the fact that the creation of an invariant container image that then gets run works very well with the Build, release, run factor and with being very explicit with Dependencies, as the whole image will include details such as the specific OS to use and any library. Including the build process as part of the repository also helps in the implementation of the Code base factor.

Each container also works as a Process, which allows scaling by creating multiple copies of the same container, using...