ctr: add EROFS image conversion support #12555
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cc @hsiangkao |
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I think the main consideration here is still how to represent mediatype, which is similar to another PR: #12506. -- We could use some non-OCI mediatypes if containerd allows them, much like the old Although there is already a PR related to this, I don't think EROFS's near-term roadmap has to be tied to OCI mediatypes, and I don't want to speak of SquashFS because whether EROFS succeeds or not in this area shouldn't be involved with other unrelated stuff (It took me a lot of time to develop several kernel features [file-backed mounts, fsmerge, external devices, etc.] in order to make EROFS suitable for both container/VM workloads). |
Cc @dmcgowan. I think after EROFS native images become successful, it will be more convincing to standardize them in OCI or other organizations, rather than just having endless theoretical discussions in meetings. |
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I have created a PR to define the erofs media type: #12567 |
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core/images/converter/erofs/erofs.go
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| } | ||
| log.G(ctx).Debugf("converted %s to EROFS using tar index mode", desc.Digest) | ||
| } else { | ||
| if err := erofsutils.ConvertTarErofs(ctx, sr, blobPath, "", convertOpts.mkfsExtraOpts); err != nil { |
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Is it possible to use erofs applier directly instead of calling erofsutils.ConvertTarErofs?
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Reusing erofsDiff.Apply is inconvenient:
- It forces output to
layer.erofsinside a mount-resolved directory. Since the converter works with temp files/streams, we'd have to hack together a fake mount.Mount object just to make it work. - It pulls in content.Store, which isn't strictly necessary for just converting streams.
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My real concern is that we should apply the differ's mkfs_options by default (unless users use an additional convertOpts.mkfsExtraOpts to overlap), and we should use the same UUID calculation: u := uuid.NewSHA1(uuid.NameSpaceURL, []byte("erofs:blobs/"+desc.Digest))
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I think at least you'd better to align the UUID calculation, I'm fine with no differ tangle.
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since there is no compress-hint files, I think you could just leave: as an example. |
Add EROFS conversion support to ctr convert command with configurable options for tar-index mode and mkfs parameters. Usage: ctr image convert --erofs src:tag dst:tag ctr image convert --erofs --erofs-compression='lz4hc,12' src:tag dst:tag Signed-off-by: ChengyuZhu6 <[email protected]>
| }, | ||
| &cli.StringFlag{ | ||
| Name: "erofs-mkfs-opts", | ||
| Usage: "Extra options for mkfs.erofs (e.g., '-zlz4')", |
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erofs-mkfs-options: Extra mkfs options applied when converting EROFS layers. (e.g. '-Efragments,dedupe')
| }, | ||
| &cli.StringFlag{ | ||
| Name: "erofs-compression", | ||
| Usage: "Compression algorithms for EROFS, separated by colon (e.g., 'lz4:lz4hc,12')", |
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just Specify compression algorithm list when converting EROFS layers,
no need to give an example since compress-hint file is unsupported for now.
| e.g., 'ctr convert --uncompress --oci example.com/foo:orig example.com/foo:converted' | ||
| 'ctr convert --erofs example.com/foo:orig example.com/foo:erofs' | ||
| 'ctr convert --erofs --erofs-compression='lzma:lz4hc,12' example.com/foo:orig example.com/foo:erofs' |
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ctr convert --erofs --erofs-compression='lz4hc,12' example.com/foo:orig example.com/foo:erofs
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Add EROFS conversion support to ctr convert command with configurable options for mkfs parameters.
Usage:
ctr image convert --erofs src:tag dst:tag
ctr image convert --erofs --erofs-compression='lz4hc,12' src:tag dst:tag
Depends-on: #12567