Container image builders, such as Docker, build images automatically by reading the instructions from a file (Dockerfile).

A Dockerfile is a text file that contains the commands that build an image. Crafting Dockerfiles to build efficient images comes with its fair share of problems and pitfalls.

Problems include, but are not limited to:

• Updating external packages
• Using the "latest" tag
• Running multiple services on a single container
• Running containers as root

The effect is inefficient, mutable and insecure container images that take a long time to build, verify and deploy.

The solution is to adhere to standard best practices when authoring Dockerfiles and building container images.

This epic covers the work to research and evaluate best practices and methods for building efficient container images. The team will issue recommendations on what best practices are applicable to ONAP container images while taking into account that ONAP is building a platform.