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Does COPY —-link allow this with BuildKit? In principle it should, in practice I’d guess it ends up pulling the base image.
by a_t48 4mo ago
Does COPY —-link allow this with BuildKit? In principle it should, in practice I’d guess it ends up pulling the base image.
- wofo 4mo agoI can't comment on BuildKit, unfortunately, since I haven't used it. My experience comes from building bespoke systems (an image builder and a custom registry) fully from scratch, because we needed to have full control in order to achieve the performance we were aiming at.
- a_t48 4mo agoI haven't gone full custom (yet), just forks (except for the pull client), but totally understand.
- wofo 4mo agoControlling both the builder and the registry is super nice btw, because they can work together. If the builder knows some of the layers already exist in the registry, it merely has to create and push the remaining ones (without downloading any of the other layers, not even those from the base image). That gives you near-instant builds once the biggest layers are cached in the registry! Since builds usually happen in CI, and pulls happen elsewhere (e.g., a kubernetes node), in the end layers are only downloaded when the resulting container image is actually used.
- a_t48 4mo agoBase image independent layers is something I’ve pondered about, but doesn’t feel compatible with things like apt. This conversation is giving me more reason to go implement lazy/fuse base layers though. My exports are already pretty fast due not not using tar+deduplication with similar layers, but pulling the base can still take several minutes.