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Merge pull request #4643 from dcantah/feedback-lcow-snapshotter

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Optimize Windows and LCOW snapshotters to only create scratch layer on the final snapshot
This commit is contained in:
Michael Crosby
2020-12-01 10:38:02 -05:00
committed by GitHub
parent 4a4bb851f5 a91c298d1d
commit b9092fae15
5 changed files with 82 additions and 56 deletions
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67
snapshots/lcow/lcow.go
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@@ -330,37 +330,44 @@ func (s *snapshotter) createSnapshot(ctx context.Context, kind snapshots.Kind, k
for _, o := range opts {
o(&snapshotInfo)
}
var sizeGB int
if sizeGBstr, ok := snapshotInfo.Labels[rootfsSizeLabel]; ok {
i32, err := strconv.ParseInt(sizeGBstr, 10, 32)
if err != nil {
return nil, errors.Wrapf(err, "failed to parse annotation %q=%q", rootfsSizeLabel, sizeGBstr)
}
sizeGB = int(i32)
}
scratchSource, err := s.openOrCreateScratch(ctx, sizeGB)
if err != nil {
return nil, err
}
defer scratchSource.Close()
// TODO: JTERRY75 - This has to be called sandbox.vhdx for the time
// being but it really is the scratch.vhdx. Using this naming convention
// for now but this is not the kubernetes sandbox.
// IO/disk space optimization
//
// Create the sandbox.vhdx for this snapshot from the cache.
destPath := filepath.Join(snDir, "sandbox.vhdx")
dest, err := os.OpenFile(destPath, os.O_RDWR|os.O_CREATE, 0700)
if err != nil {
return nil, errors.Wrap(err, "failed to create sandbox.vhdx in snapshot")
}
defer dest.Close()
if _, err := io.Copy(dest, scratchSource); err != nil {
dest.Close()
os.Remove(destPath)
return nil, errors.Wrap(err, "failed to copy cached scratch.vhdx to sandbox.vhdx in snapshot")
// We only need one sandbox.vhd for the container. Skip making one for this
// snapshot if this isn't the snapshot that just houses the final sandbox.vhd
// that will be mounted as the containers scratch. Currently the key for a snapshot
// where a layer.vhd will be extracted to it will have the string `extract-` in it.
// If this is changed this will also need to be changed.
//
// We save about 17MB per layer (if the default scratch vhd size of 20GB is used) and of
// course the time to copy the vhd per snapshot.
if !strings.Contains(key, snapshots.UnpackKeyPrefix) {
var sizeGB int
if sizeGBstr, ok := snapshotInfo.Labels[rootfsSizeLabel]; ok {
i32, err := strconv.ParseInt(sizeGBstr, 10, 32)
if err != nil {
return nil, errors.Wrapf(err, "failed to parse label %q=%q", rootfsSizeLabel, sizeGBstr)
}
sizeGB = int(i32)
}
scratchSource, err := s.openOrCreateScratch(ctx, sizeGB)
if err != nil {
return nil, err
}
defer scratchSource.Close()
// Create the sandbox.vhdx for this snapshot from the cache.
destPath := filepath.Join(snDir, "sandbox.vhdx")
dest, err := os.OpenFile(destPath, os.O_RDWR|os.O_CREATE, 0700)
if err != nil {
return nil, errors.Wrap(err, "failed to create sandbox.vhdx in snapshot")
}
defer dest.Close()
if _, err := io.Copy(dest, scratchSource); err != nil {
dest.Close()
os.Remove(destPath)
return nil, errors.Wrap(err, "failed to copy cached scratch.vhdx to sandbox.vhdx in snapshot")
}
}
}