Federation implementation roadmap¶

Use a remote-hosted workflow

• 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) in a container - Federated collections

• (controller) fetch remote-hosted container by UUID (similar to workflow case)
• (controller) rewrite locators in manifest to indicate remote cluster
• (keepstore) if locator indicates remote cluster and data does not exist locally (or local signature is not supplied), fetch from remote using salted token
• When creating a container to satisfy a CR, API searches for collection PDH in cr.mounts across federated nodes, and fetches it with salted token (instead of looking in local DB)

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
• Either a-c-r handles the multi-cluster stuff itself, or it submits CRs with "submit to cluster X" flag, and the API server acts as a proxy