Harbor is an open source trusted cloud native registry project that stores, signs, and scans content.
The mission is to provide Cloud Native environments the ability to confidently manage and serve container images and related artifacts.
Data Access Layer :
k-v storage : formed by Redis, provides data cache functions and supports temporarily persisting job metadata for the job service.
data storage : multiple storages supported for data persistence as backend storage of registry and chart museum. For checking more details, please refer to the driver list document at docker website and ChartMuseum GitHub repository.
Database : stores the related metadata of Harbor models, like projects, users, roles, replication policies, tag retention policies, scanners, charts, and images. PostgreSQL is adopted.
Fundamental Services :
reverse-proxy formed by the Nginx Server to provide API routing capabilities. Components of Harbor, such as core, registry, web portal, and token services, etc., are all behind this reversed proxy. The proxy forwards requests from browsers and Docker clients to various backend services.
Harbor’s core service, which mainly provides the following functions:
- API Server:
A HTTP server accepting REST API requests and responding those requests rely on its submodules such as ‘Authentication & Authorization’, ‘Middleware’, and ‘API Handlers’.
- Authentication & Authorization
- requests are protected by the authentication service which can be powered by a local database, AD/LDAP or OIDC.
- RBAC mechanism is enabled for performing authorizations to the related actions, e.g: pull/push an image
- Token service is designed for issuing a token for every docker push/pull command according to a user’s role of a project. If there is no token in a request sent from a Docker client, the Registry will redirect the request to the token service.
Preprocess some requests in advance to determine whether they match the required criteria and can be passed to the backend components for further processing or not. Some functions are implemented as kinds of middleware, such as ‘quota management’, ‘signature check’, ‘vulnerability severity check’ and ‘robot account parsing’ etc.
- API Handlers:
Handle the corresponding REST API requests, mainly focus on parsing and validating request parameters, completing business logic on top of the relevant API controller, and writing back the generated response.
- Authentication & Authorization
- Config Manager:
Covers the management of all the system configurations, like authentication type settings, email settings, and certificates, etc..
- Project Management:
Manages the base data and corresponding metadata of the project, which is created to isolate the managed artifacts.
- Quota Manager:
Manages the quota settings of projects and performs the quota validations when new pushes happened.
- Chart Controller:
Proxy the chart related requests to backend
chartmuseumand provides several extensions to improve chart management experiences.
- Retention Manager:
Manages the tag retention policies and perform and monitor the tag retention processes
- Content Trust:
add extensions to the trust capability provided by backend Notary to support the smoothly content trust process. At present, only container images are supported to sign.
- Replication Controller:
Manages the replication policies and registry adapters, triggers and monitors the concurrent replication processes. Many registry adapters are implemented:
- Distribution (docker registry)
- Docker Hub
- Huawei SWR
- Amazon ECR
- Google GCR
- Azure ACR
- Ali ACR
- Helm Hub
- GitLab Registry
- Scan Manager:
Manages the multiple configured scanners adapted by different providers and also provides scan summaries and reports for the specified artifacts.
Trivyscanner provided by Aqua Security, the
Anchore Enginescanner provided by Anchore, the
Clairscanner sponsored by CentOS (Redhat), and
DoSec Scannerprovided by DoSec will be supported.
- At present, only container images or bundles are built on top of images like the manifest list/OCI index or CNAB bundle are supported to scan.
- Notification Manager(webhook):
A mechanism configured in Harbor so that artifact status changes in Harbor can be populated to the Webhook endpoints configured in Harbor. The interested parties can trigger some follow-up actions by listening to the related webhook events. Now, two ways are supported:
- HTTP Post request
- Slack channel
- OCI Artifact Manager:
Core component to manage the lifecycle of all the OCI artifacts across the whole Harbor registry. It provides the CRUD operations to manage the metadata and related additions such as scanning report, building history of container images and readme, dependencies, and value.yaml of helm charts, etc. of the artifact, it also supports the capabilities of managing artifact tags and other helpful operations.
- Registry Driver:
Implemented as a registry client SDK to do communications with the underlying registry (docker distribution at this moment). ‘OCI Artifact Manager’ relies on this driver to get additional info from the manifest and even config JSON of the specified artifact that located at the underlying registry.
General job execution queue service to let other components/services submit requests of running asynchronous tasks concurrently with simple restful APIs
Log collector, responsible for collecting logs of other modules into a single place.
manages the online GC schedule settings and start and track the GC progress.
A 3rd party chart repository server providing chart management and access APIs. To learn more details, check here.
A 3rd party registry server, responsible for storing Docker images and processing Docker push/pull commands. As Harbor needs to enforce access control to images, the Registry will direct clients to a token service to obtain a valid token for each pull or push request.
a 3rd party content trust server, responsible for securely publishing and verifying content. To learn more details, check here.
As a standard cloud-native artifact registry, the related clients will be naturally supported, like docker CLI, notary client, OCI compatible client like Oras, and Helm. Besides those clients, Harbor also provides a web portal for the administrators to easily manage and monitor all the artifacts.
a graphical user interface to help users manage images on the Registry
- Cloud native registry: With support for both container images and Helm charts, Harbor serves as registry for cloud native environments like container runtimes and orchestration platforms.
- Role based access control: Users access different repositories through ‘projects’ and a user can have different permission for images or Helm charts under a project.
- Policy based replication: Images and charts can be replicated (synchronized) between multiple registry instances based on policies with using filters (repository, tag and label). Harbor automatically retries a replication if it encounters any errors. This can be used to assist loadbalancing, achieve high availabiliy, and faciliate multi-datacenter deployments in hybrid and multi-cloud scenarios.
- Vulnerability Scanning: Harbor scans images regularly for vulnerabilities and has policy checks to prevent vulnerable images from being deployed.
- LDAP/AD support: Harbor integrates with existing enterprise LDAP/AD for user authentication and management, and supports importing LDAP groups into Harbor that can then be given permissions to specific projects.
- OIDC support: Harbor leverages OpenID Connect (OIDC) to verify the identity of users authenticated by an external authorization server or identity provider. Single sign-on can be enabled to log into the Harbor portal.
- Image deletion & garbage collection: System admin can run garbage collection jobs so that images(dangling manifests and unreferenced blobs) can be deleted and their space can be freed up periodically.
- Notary: Support signing container images using Docker Content Trust (leveraging Notary) for guaranteeing authenticity and provenance. In additon, policies that prevent unsigned images from being deployed can also be activated.
- Graphical user portal: User can easily browse, search repositories and manage projects.
- Auditing: All the operations to the repositories are tracked through logs.
- RESTful API: RESTful APIs are provided to facilitate administrative operations, and are easy to use for integration with external systems. An embedded Swagger UI is available for exploring and testing the API.
- Easy deployment: Harbor can be deployed via Docker compose as well Helm Chart, and a Harbor Operator was added recently as well.
Reference link :