coreweave-data-handling

What this skill does

# CoreWeave Data Handling

## Overview

CoreWeave GPU cloud workloads involve large-scale data artifacts: model weights (multi-GB safetensors/GGUF), training datasets (parquet, TFRecord, WebDataset), checkpoint snapshots, and inference cache volumes. Data flows through Kubernetes PersistentVolumeClaims backed by region-specific storage classes. Compliance requires encryption at rest via the storage driver, namespace-scoped RBAC for volume access, and audit logging for any data egress from GPU nodes.

## Data Classification

| Data Type | Sensitivity | Retention | Encryption |
|-----------|-------------|-----------|------------|
| Model weights | Medium | Until deprecated | AES-256 at rest |
| Training datasets | High (may contain PII) | Per data license | AES-256 + TLS in transit |
| Checkpoint snapshots | Medium | 30 days post-training | AES-256 at rest |
| Inference cache | Low | Session/TTL | Volume-level encryption |
| HuggingFace tokens | Critical | Rotate quarterly | K8s Secret + KMS |

## Data Import

```typescript
import { KubeConfig, BatchV1Api } from '@kubernetes/client-node';

async function importDataset(pvcName: string, sourceUrl: string, namespace: string) {
  const kc = new KubeConfig();
  kc.loadFromDefault();
  const batch = kc.makeApiClient(BatchV1Api);
  const job = {
    metadata: { name: `import-${Date.now()}`, namespace },
    spec: { template: { spec: {
      restartPolicy: 'Never',
      containers: [{ name: 'loader', image: 'python:3.11-slim',
        command: ['python3', '-c', `
import urllib.request, hashlib
dest = '/data/dataset.tar.gz'
urllib.request.urlretrieve('${sourceUrl}', dest)
print(f"SHA256: {hashlib.sha256(open(dest,'rb').read()).hexdigest()}")`],
        volumeMounts: [{ name: 'storage', mountPath: '/data' }],
      }],
      volumes: [{ name: 'storage', persistentVolumeClaim: { claimName: pvcName } }],
    }}}
  };
  await batch.createNamespacedJob(namespace, { body: job });
}
```

## Data Export

```typescript
async function exportCheckpoint(pvcName: string, destBucket: string, ns: string) {
  // Validate export destination is in approved region list
  const APPROVED_REGIONS = ['us-east-1', 'us-central-1', 'eu-west-1'];
  const region = destBucket.split('-').slice(0, 3).join('-');
  if (!APPROVED_REGIONS.some(r => destBucket.includes(r))) {
    throw new Error(`Export blocked: ${region} not in approved regions`);
  }
  // Stream from PVC → object storage with integrity check
  const exportCmd = `tar czf - /models | gsutil cp - gs://${destBucket}/export.tar.gz`;
  console.log(`Exporting from PVC ${pvcName} to ${destBucket}`);
  return exportCmd;
}
```

## Data Validation

```typescript
interface ModelArtifact {
  name: string; format: 'safetensors' | 'gguf' | 'bin' | 'pt';
  sizeBytes: number; sha256: string;
}

function validateArtifact(artifact: ModelArtifact): string[] {
  const errors: string[] = [];
  if (!artifact.name || artifact.name.length > 255) errors.push('Invalid artifact name');
  if (artifact.sizeBytes <= 0) errors.push('Size must be positive');
  if (!/^[a-f0-9]{64}$/.test(artifact.sha256)) errors.push('Invalid SHA-256 hash');
  if (!['safetensors', 'gguf', 'bin', 'pt'].includes(artifact.format)) errors.push(`Unsupported format`);
  return errors;
}
```

## Compliance

- [ ] All PVCs use encrypted storage classes (AES-256 at rest)
- [ ] HuggingFace and API tokens stored in Kubernetes Secrets with KMS encryption
- [ ] Namespace-scoped RBAC restricts volume mount access to authorized workloads
- [ ] Data egress from GPU nodes logged via network policy audit
- [ ] Training datasets with PII processed only in approved regions (data residency)
- [ ] Checkpoint retention enforced via CronJob garbage collection (30-day default)
- [ ] SOC 2 Type II audit trail for all storage provisioning and deletion events

## Error Handling

| Issue | Cause | Fix |
|-------|-------|-----|
| PVC pending indefinitely | Storage class unavailable in region | Check `kubectl get sc` and switch to available class |
| Download job OOMKilled | Dataset exceeds container memory limit | Increase resource limits or use streaming download |
| Permission denied on volume | RBAC misconfigured for namespace | Verify ServiceAccount has PVC access via RoleBinding |
| Checksum mismatch after import | Partial transfer or corruption | Re-run import job; enable retry with backoff |
| Secret not found | KMS key rotation or namespace mismatch | Verify secret exists in target namespace with `kubectl get secret` |

## Resources

- CoreWeave Storage Docs
- [Kubernetes PVC Reference](https://kubernetes.io/docs/concepts/storage/persistent-volumes/)

## Next Steps

See `coreweave-security-basics`.