Scenario: A developer, Alice, is working on a project that involves distributing container images to a team. She wants to ensure that only specific team members have access to certain images. OCI Distribution supports access control through the use of registry authentication and authorization policies. Alice can define policies that restrict access to specific images based on user roles, IP addresses, or other criteria.
To implement access control for container images using OCI, follow these steps:
- Understand OCI and its specifications:
Before implementing access control, it’s essential to understand the Open Container Initiative (OCI) and its specifications. OCI is an open-source organization that develops and maintains specifications for container formats, runtime environments, and distribution.
- OCI Image Format Specification: https://edu.chainguard.dev/open-source/oci/what-is-the-oci
- OCI Distribution Specification: https://oras.land/docs/concepts/reference
- Set up an OCI-compliant registry:
To implement access control, you need an OCI-compliant registry. Popular options include Docker Hub, Amazon Elastic Container Registry (ECR), and Google Container Registry (GCR).
- Create a new repository in the registry:
Create a new repository in your chosen registry for the images you want to control access to.
- Configure authentication:
Configure authentication for your registry. OCI supports various authentication methods, including username/password, tokens, and certificates. Choose the method that best fits your use case.
- Define access control policies:
Define access control policies for your repository using the registry’s web interface or API. Policies can be based on user roles, IP addresses, or other criteria.
- Test access control:
Test your access control policies by attempting to pull images with different credentials. Ensure that only authorized users can access the restricted images.
- Automate access control:
If you’re using a CI/CD pipeline, automate access control by integrating your pipeline with your registry’s API. This way, you can automatically apply access control policies to new images as they’re pushed to the registry.
- Monitor and manage access control:
Regularly review and manage your access control policies to ensure they’re up-to-date and effective.
Tests:
- Attempt to pull a restricted image using unauthorized credentials.
- Attempt to pull a restricted image using authorized credentials.
- Create a new repository and define access control policies.
- Attempt to push an image to a restricted repository using unauthorized credentials.
- Attempt to push an image to a restricted repository using authorized credentials.
- Verify that the image is accessible only to authorized users.
- Update access control policies and verify their effect.