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diff --git a/doc/architecture/blueprints/cells/cells-feature-container-registry.md b/doc/architecture/blueprints/cells/cells-feature-container-registry.md index 25af65a8700..d9ff6da7f62 100644 --- a/doc/architecture/blueprints/cells/cells-feature-container-registry.md +++ b/doc/architecture/blueprints/cells/cells-feature-container-registry.md @@ -1,114 +1,6 @@ --- -stage: enablement -group: Tenant Scale -description: 'Cells: Container Registry' +redirect_to: 'impacted_features/container-registry.md' +remove_date: '2023-11-17' --- -<!-- vale gitlab.FutureTense = NO --> - -This document is a work-in-progress and represents a very early state of the -Cells design. Significant aspects are not documented, though we expect to add -them in the future. This is one possible architecture for Cells, and we intend to -contrast this with alternatives before deciding which approach to implement. -This documentation will be kept even if we decide not to implement this so that -we can document the reasons for not choosing this approach. - -# Cells: Container Registry - -GitLab [Container Registry](../../../user/packages/container_registry/index.md) is a feature allowing to store Docker container images in GitLab. - -## 1. Definition - -GitLab Container Registry is a complex service requiring usage of PostgreSQL, Redis and Object Storage dependencies. -Right now there's undergoing work to introduce [Container Registry Metadata](../container_registry_metadata_database/index.md) to optimize data storage and image retention policies of Container Registry. - -GitLab Container Registry is serving as a container for stored data, but on its own does not authenticate `docker login`. -The `docker login` is executed with user credentials (can be `personal access token`) or CI build credentials (ephemeral `ci_builds.token`). - -Container Registry uses data deduplication. -It means that the same blob (image layer) that is shared between many Projects is stored only once. -Each layer is hashed by `sha256`. - -The `docker login` does request a JWT time-limited authentication token that is signed by GitLab, but validated by Container Registry service. -The JWT token does store all authorized scopes (`container repository images`) and operation types (`push` or `pull`). -A single JWT authentication token can have many authorized scopes. -This allows Container Registry and client to mount existing blobs from other scopes. -GitLab responds only with authorized scopes. -Then it is up to GitLab Container Registry to validate if the given operation can be performed. - -The GitLab.com pages are always scoped to a Project. -Each Project can have many container registry images attached. - -Currently, on GitLab.com the actual registry service is served via `https://registry.gitlab.com`. - -The main identifiable problems are: - -- The authentication request (`https://gitlab.com/jwt/auth`) that is processed by GitLab.com. -- The `https://registry.gitlab.com` that is run by an external service and uses its own data store. -- Data deduplication. The Cells architecture with registry run in a Cell would reduce efficiency of data storage. - -## 2. Data flow - -### 2.1. Authorization request that is send by `docker login` - -```shell -curl \ - --user "username:password" \ - "https://gitlab/jwt/auth?client_id=docker&offline_token=true&service=container_registry&scope=repository:gitlab-org/gitlab-build-images:push,pull" -``` - -Result is encoded and signed JWT token. Second base64 encoded string (split by `.`) contains JSON with authorized scopes. - -```json -{"auth_type":"none","access":[{"type":"repository","name":"gitlab-org/gitlab-build-images","actions":["pull"]}],"jti":"61ca2459-091c-4496-a3cf-01bac51d4dc8","aud":"container_registry","iss":"omnibus-gitlab-issuer","iat":1669309469,"nbf":166} -``` - -### 2.2. Docker client fetching tags - -```shell -curl \ - -H "Accept: application/vnd.docker.distribution.manifest.v2+json" \ - -H "Authorization: Bearer token" \ - https://registry.gitlab.com/v2/gitlab-org/gitlab-build-images/tags/list - -curl \ - -H "Accept: application/vnd.docker.distribution.manifest.v2+json" \ - -H "Authorization: Bearer token" \ - https://registry.gitlab.com/v2/gitlab-org/gitlab-build-images/manifests/danger-ruby-2.6.6 -``` - -### 2.3. Docker client fetching blobs and manifests - -```shell -curl \ - -H "Accept: application/vnd.docker.distribution.manifest.v2+json" \ - -H "Authorization: Bearer token" \ - https://registry.gitlab.com/v2/gitlab-org/gitlab-build-images/blobs/sha256:a3f2e1afa377d20897e08a85cae089393daa0ec019feab3851d592248674b416 -``` - -## 3. Proposal - -### 3.1. Shard Container Registry separately to Cells architecture - -Due to its extensive and in general highly scalable horizontal architecture it should be evaluated if the GitLab Container Registry should be run not in Cell, but in a Cluster and be scaled independently. -This might be easier, but would definitely not offer the same amount of data isolation. - -### 3.2. Run Container Registry within a Cell - -It appears that except `/jwt/auth` which would likely have to be processed by Router (to decode `scope`) the Container Registry could be run as a local service of a Cell. -The actual data at least in case of GitLab.com is not forwarded via registry, but rather served directly from Object Storage / CDN. - -Its design encodes container repository image in a URL that is easily routable. -It appears that we could re-use the same stateless Router service in front of Container Registry to serve manifests and blobs redirect. - -The only downside is increased complexity of managing standalone registry for each Cell, but this might be desired approach. - -## 4. Evaluation - -There do not seem to be any theoretical problems with running GitLab Container Registry in a Cell. -It seems that the service can be easily made routable to work well. -The practical complexities are around managing a complex service from an infrastructure side. - -## 4.1. Pros - -## 4.2. Cons +This document was moved to [another location](impacted_features/container-registry.md). |