  Linux containers have risen in popularity in the last few years, making their
way to commercial IT service offerings (such as PaaS), application deployments,
and Continuous Delivery/Integration pipelines within various development teams.
Along with the wide adoption of Docker, security vulnerabilities and concerns
have also surfaced. In this survey, we examine the state of security for the
most popular container system at the moment: Docker. We will also look into its
origins stemming from the Linux technologies built into the OS itself; examine
intrinsic vulnerabilities, such as the Docker Image implementation; and provide
an analysis of current tools and modern methodologies used in the field to
evaluate and enhance its security. For each section, we pinpoint metrics of
interest, as they have been revealed by researchers and experts in the domain
and summarize their findings to paint a holistic picture of the efforts behind
those findings. Lastly, we look at tools utilized in the industry to streamline
Docker security scanning and analytics which provide built-in aggregation of
key metrics.
