build: improve build reproducibility#8549
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jsha merged 3 commits intoletsencrypt:mainfrom Feb 10, 2026
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- Add -trimpath to Go builds - Use commit timestamp for BuildTime ldflags - Set SOURCE_DATE_EPOCH for build tools - Normalize timestamps in .deb packages - Add reproducible tar options (--mtime, --owner, --group, --sort) - Use commit timestamp for container image label
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beautifulentropy
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LGTM but I'd love to have @jsha's eyes on this too.
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Remove sources of non-determinism in the build process.
Changes
-trimpathto Go builds (strips file paths from binaries)BuildTimeldflags instead of$(date -u)$(date +%s)SOURCE_DATE_EPOCHenvironment variable.debpackages--mtime,--owner,--group,--sort)What this achieves
Builds on the same OS/toolchain now produce identical artifacts. Verified by running try-release twice on the same commit—both produced identical SHA256 checksums.
What this does NOT address
Full reproducibility across different build environments would additionally require:
This PR addresses the low-hanging fruit; cross-environment reproducibility is out of scope.
Files Modified
Containerfiletools/container-build.shtools/make-deb.shtest/ct-test-srv/Dockerfile