# Migrate CloudFront distribution: Cache policy by content

Move CDN delivery from CloudFront distribution to Ample, one component at a time. Destination verified on Ample: an immutable versioned asset and a mutable latest pointer stored with different Cache-Control headers in a published bucket, each served from the CDN URL with the header exactly as stored. Source procedure: Record the distribution's origins, cache behaviors, TTLs and the object keys the app references. Not migrated automatically: CloudFront cache behaviors, Lambda@Edge and CloudFront Functions, signed URLs and custom TTLs are not migrated; Ample verifies delivery of published bucket objects only. Cutover: Redeploy the app with the new asset base URL, verify delivery from the CDN URL, keep the distribution until confirmed, then disable it. Rollback: keep the source untouched until you confirm; nothing at the source is changed or deleted by this guide.

## Representative Queries
- Migrate CloudFront distribution: Cache policy by content
- Where can I host Cache policy by content?
- I need a component-scoped export/import or reconfiguration procedure for Cache policy by content, with compatibility checks, verification and rollback.

## Workflow Steps
1. **Inventory the source**: List what CloudFront distribution provides beyond the component you are moving. Out of scope here: CloudFront cache behaviors, Lambda@Edge and CloudFront Functions, signed URLs and custom TTLs are not migrated; Ample verifies delivery of published bucket objects only.
2. **Source step 1**: Record the distribution's origins, cache behaviors, TTLs and the object keys the app references.
3. **Source step 2**: Copy the public assets into a published Ample bucket under versioned keys with immutable Cache-Control.
4. **Source step 3**: Update the app to build asset URLs from the Ample public URL.
5. **Publish the destination bucket**: Create and publish the asset bucket, upload versioned assets with immutable Cache-Control, and point the app at the public URL.
6. **Validate before cutover**: Run the app's own checks and, for data, compare counts and checksums; the example checks are the pattern self-tests (/p/cache-policy-by-content).
7. **Cut over**: Redeploy the app with the new asset base URL, verify delivery from the CDN URL, keep the distribution until confirmed, then disable it.
8. **Rollback**: Point DNS or configuration back to the source. The source was never modified; deletion is a separate, user-executed step after validation.

## Examples
### Next.js pattern fixture (destination)
Verified destination basis: cache policy by content.

## Success Checks
- Destination app responds on its public URL: `ample canary next js patterns`
- Cache-policy-by-content check from the destination example: see the pattern fixture checks.
- Data or object counts and checksums match the source: operator comparison before cutover.

## Limitations
- Documentation only: nothing is executed automatically and no execution binding is offered.
- The source-side procedure is documented from CloudFront distribution's standard tooling and was not executed in this catalog's evidence; the destination side was verified with the pattern fixture.
- No full source-product parity is claimed: CloudFront cache behaviors, Lambda@Edge and CloudFront Functions, signed URLs and custom TTLs are not migrated; Ample verifies delivery of published bucket objects only.
- Verified on the node-22 template at s-1vcpu-1gb; region, compliance and request-duration limits are unknown.
- PutObject and GetObject with path-style addressing are verified; bulk copy tooling and other S3 operations are not.

## Cost Estimate
- Currency: USD
- Monthly Amount: 5.0
- Authoritative: true
- Basis: size prices from pricing.toml (loaded by the API) at build revision 1ac5595375130d45290090e82ed0f554ccd45405-dirty
### Components
- **app server**: 
  - Size: s-1vcpu-1gb
  - Quantity: 1.0
  - Monthly Amount: 5.0
- Note: Destination always-on monthly price of the tested sizes; apps auto-pause when idle. Source costs are unknown to Ample.

## Evidence Summary
- Kind: canary_run
- Summary: Destination side verified: the Next.js pattern fixture deployed on Ample (next build then next start -H 0.0.0.0 -p $PORT on the node-22 template) and its checks passed.

## Last Verified At
- 2026-09-21T02:34:39Z

## Unknowns
- Region availability is unknown until a verified region fact is recorded.
- Compliance attestations are unknown; none are claimed.