Goal

Enable configuration of additional artifact storage locations in CRI-O, allowing users to specify where OCI volume images can be pulled from. This addresses the problem where large AI/ML models need to be stored on high-performance storage (SSD) separate from OS/container storage, improving pod startup times and storage utilization.

Why is this important?

• Large AI/ML models need to be stored on high-performance storage (SSD) for faster access
• CRI-O currently hardcodes all artifacts to /var/lib/containers/storage/artifacts/, preventing use of dedicated storage
• Cannot pre-populate shared artifact caches across cluster nodes for air-gapped or edge deployments
• RHOAI workloads suffer from slow model loading and inefficient storage utilization
• Root filesystem space consumed by large artifacts that should be on separate storage

Scenarios

1. As a RHOAI Platform Operator, I want to store large ML models on SSD storage, so that model loading is faster and doesn't consume root filesystem space
2. As a Cluster Admin in an air-gapped environment, I want to pre-populate artifact caches on nodes, so that pods can start without pulling from external registries
3. As an Edge Deployment Operator, I want to deliver artifacts via removable media (USB), so that edge nodes can operate offline without network connectivity

Acceptance Criteria

• CI - MUST be running successfully with tests automated
• Release Technical Enablement - Provide necessary release enablement details and documents
• ContainerRuntimeConfig API accepts additionalArtifactStores configuration with path and optional filter fields
• MCO generates correct CRI-O config from API (storage.conf with additional_artifact_stores)
• CRI-O resolves artifacts from additional stores in configured order
• RHOAI team validates measurable performance improvement with SSD storage
• Feature behind TechPreviewNoUpgrade feature gate for OpenShift 4.22
• No regressions for existing artifact storage behavior
• Documentation available with clear examples for common scenarios

Dependencies (internal and external)

1. Critical Path: CRI-O v1.36 release (April 2026) with PR #9702 merged
2. Upstream: CRI-O PR #9702 (https://github.com/cri-o/cri-o/pull/9702) - adds additional_artifact_stores configuration
3. OpenShift: Enhancement proposal approval covering both additionalLayerStores and additionalArtifactStores API design
4. OpenShift: API merge in openshift/api before MCO implementation
5. External: RHOAI team (Luca Burgazzoli) for performance validation
6. Documentation: OSDOCS-17312 - Tech Preview feature documentation
7. Backport consideration: If API work lands for 4.22, may need to backport CRI-O v1.36 PR to v1.35
8. Related: OCPNODE-4050 (Additional Layer Store Support) - shares enhancement proposal and MCO implementation

Previous Work (Optional):

1. RFE-8441 - Related feature request for artifact pre-loading (separate feature, out of scope)
2. Proven pattern: containers/storage additionalimagestores approach

Open questions:

1. Will CRI-O v1.36 be available in time for OpenShift 4.22? (April 2026 upstream release)
2. Do we need to backport PR #9702 to CRI-O v1.35 if 4.22 timeline is tight?
3. Should we defer upstream Kubernetes KEP until after Tech Preview validation?
4. What are the performance benchmarks we should target with RHOAI validation?

Done Checklist

• CI - CI is running, tests are automated and merged.
• Release Technical Enablement <link to Feature Enablement Presentation>
• DEV - Upstream code and tests merged: <link to CRI-O PR #9702>
• DEV - Enhancement proposal merged: <link to openshift/enhancements PR>
• DEV - API changes merged: <link to openshift/api PR>
• DEV - MCO implementation merged: <link to openshift/machine-config-operator PR>
• DEV - Downstream build attached to advisory: <link to errata>
• QE - Test plans in Polarion: <link or reference to Polarion>
• QE - Automated tests merged: <link or reference to automated tests>
• QE - RHOAI validation complete: <link to validation results>
• DOC - Downstream documentation merged: <link to OSDOCS-17312 PR>