alt Hacker NewsRecompressing should be guaranteed deterministic. It’s the packing/unpacking of tar archives to/from directories on disk that leads to the non-determinism (such as timestamps and ownership metadata). If the tar is left intact, both zstd and gzip should produce byte for byte identical outputs given the same compression parameters.
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XYen0n • today at 7:56 PM
You are correct; I confused archiving with compression. However, even considering only the compression process, same compression parameters cannot be guaranteed, as it is unknown which compression parameters the image publisher used.
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That is not correct. You would have to use the same compression tool (and likely version) for this to match.
Old docker discarded the compressed bits but kept some metadata about the the so it can at least recreate the tar.
It also recreated the manifest o push.