Federation implementation roadmap¶

Use a remote-hosted workflow #13493

• When retrieving a workflow record for arvados-cwl-runner, API server notices workflow UUID is remote, and fetches it with salted token (instead of looking in local DB)

Mount remote-hosted collection (read-only) - Federated collections

• (controller) fetch remote-hosted container by UUID (similar to workflow case) (#13993)
• (controller) rewrite locators in manifest to indicate remote cluster (#13993)
• (keepstore) if locator indicates remote cluster and data does not exist locally (or local signature is not supplied), fetch from remote using salted token (#13994)

Mount remote-hosted collection (read-only) in a container

• When creating a container to satisfy a CR, Rails API assumes any PDH appearing in the CR mounts is OK.
• When running the container, arv-mount (and any other client) will go through the controller to get the collection.
• The controller will search the federation for any PDH not found (or not readable by the acting user) in the local DB. (#14087)

Run some portions of a CWL workflow on a remote cluster

• When submitting container requests, a-c-r follows workflow/commandline/input UUID hints to choose a cluster.
• a-c-r submits CRs to its default cluster with "submit to cluster X" flag, and the controller proxies those requests to remote clusters.
• When a-c-r requests a batch of containers, the controller proxies requests to remotes as needed to get a full response (#13619)
• This might require changes/additions to the list API