What is Anchore Engine?

Anchore Engine is an open-source Docker container static analysis and policy-based compliance tool that automates the inspection, analysis, and evaluation of images against user-defined checks to allow high confidence in container deployments by ensuring workload content meets the required criteria. Anchore Engine ultimately provides a policy evaluation result for each image: pass/fail against policies defined by the user. Additionally, the way that policies are defined and evaluated allows the policy evaluation itself to double as an audit mechanism that allows point-in-time evaluations of specific image properties and content attributes.

How does it work?

Anchore takes a data-driven approach to analysis and policy enforcement. The system essentially has discrete phases for each image analyzed:

  • Fetch the image content and extract it, but never execute it
  • Analyze the image by running a set of Anchore analyzers over the image content to extract and classify as much metadata as possible
  • Save the resulting analysis in the database for future use and audit
  • Evaluate policies against the analysis result, including vulnerability matches on the artifacts discovered in the image
  • Update to the latest external data used for policy evaluation and vulnerability matches (we call this external data sync a feed sync), and automatically update image analysis results against any new data found upstream.
  • Notify users of changes to policy evaluations and vulnerability matches Repeat 5 & 6 on intervals to ensure latest external data and updated image evaluations

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The primary interface is a RESTful API that provides mechanisms to request analysis, policy evaluation, and monitoring of images in registries as well as query for image contents and analysis results. We also provide a CLI and its own container.

There are, generally speaking, two different ways to use Anchore, within its single API:

  • Interactive Mode - Use the APIs to explicitly request an image analysis, get a policy evaluation and content reports, but the engine only performs operations when specifically requested by a user
  • Watch Mode - Use the APIs to configure Anchore Engine to poll specific registries and repositories/tags to watch for new images added and automatically pull and evaluate them, emitting notifications when a given tag’s vulnerability or policy evaluation state changes

With these two modes of operation, integration into CI/CD with Interative Mode or less intrusive watching of production image repositories with Watch Mode, Anchore can be easily integrated into most environments and processes.