thaloco/banger
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make-bundle: strip /.dockerenv so systemd doesn't misdetect virt

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`docker create` drops /.dockerenv into the container's writable layer,
and `docker export` includes it in the tar. When systemd later boots
that rootfs it finds /.dockerenv and flags virtualization=docker,
which disables a bunch of udev device-unit behaviour (device units
never become active, mount units waiting on them hang forever).
Strip /.dockerenv (and /run/.containerenv for podman symmetry) from
the staging tree after FlattenTar and before BuildExt4 so systemd
correctly detects virtualization=kvm.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
This commit is contained in:
Thales Maciel 2026-04-18 14:58:42 -03:00
parent ed4117d926
commit 66838bb135
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GPG key ID: 33112E6833C34679
1 changed files with 15 additions and 0 deletions
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15
internal/cli/banger.go
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@ -421,6 +421,21 @@ func runInternalMakeBundle(cmd *cobra.Command, opts internalMakeBundleOpts) erro
return fmt.Errorf("flatten rootfs: %w", err)
}
// docker create drops /.dockerenv (and containerd drops
// /run/.containerenv) into the container's writable layer, so
// `docker export` includes them in the tar. systemd-detect-virt
// reads those files and flags the boot as virtualization=docker,
// which disables udev device-unit activation (including the work-
// disk dev-vdb.device) and leaves systemd waiting forever. Strip
// them before building the ext4.
for _, marker := range []string{".dockerenv", "run/.containerenv"} {
path := filepath.Join(rootfsTree, marker)
if err := os.Remove(path); err != nil && !os.IsNotExist(err) {
return fmt.Errorf("strip %s: %w", marker, err)
}
delete(meta.Entries, marker)
}
if sizeBytes <= 0 {
treeSize, err := dirSize(rootfsTree)
if err != nil {