Developer Enablement Briefing — March 28, 2024

Executive briefing: GitHub increased the Actions cache limit from 5 GB to 10 GB per key across GitHub-hosted and self-hosted runners, allowing larger dependency graphs to persist between workflow runs without external object stores.¹ Platform teams can now retain expansive Node.js, Android, and Python environments or compiled artefacts for nightly builds, but they need updated integrity checks and monitoring so caches do not mask supply-chain drift.

Key industry signals

Double the capacity. Each cache key now supports up to 10 GB, enabling bundling of language runtimes, GPU wheels, and container layers that previously required bespoke blob storage.¹
Cache eviction unchanged. GitHub retains least-recently-used eviction at the repository level, so teams must still pin critical caches and schedule refreshes to avoid noisy cache misses.¹
Compression optionality. GitHub recommends Zstandard compression and chunked uploads to stay under the limit while keeping restore times predictable for matrix builds.²

Control alignment

NIST SP 800-53 Rev. 5 CM-2. Update configuration baselines to document cache key naming, retention periods, and hash inputs for every regulated build workflow.
NIST SP 800-53 Rev. 5 SI-7. Integrate cache integrity verification—checksum validation and signature checks—into pipelines before artefacts are restored to runners.
ISO/IEC 27001:2022 Annex A.8.28. Extend secure coding standards to include cache review steps so developers validate dependency provenance when caches exceed previous thresholds.

Detection and response priorities

Alert when cache restore hits approach the 10 GB ceiling or start failing, indicating pipelines that require segmentation.
Track cache hit ratios alongside build durations—sustained drops can reveal corrupted entries or dependency drift.
Monitor for cache keys that skip checksum validation scripts or bypass signed package registries.

Enablement moves

Publish updated caching playbooks covering language-specific strategies (Gradle, pnpm, pip) and the new size ceiling.
Stage rehearsal workflows that deliberately rotate cache keys after critical updates to ensure rebuild times and observability dashboards remain accurate.
Coordinate with finance to capture storage consumption trends, ensuring the expanded limit does not inflate Actions usage forecasts.

Sources

Zeph Tech equips platform teams with caching playbooks, integrity automation, and budget guardrails so CI/CD velocity gains never compromise supply-chain assurance.