Missing initrd.img-core in os.snap

Metadata

Project: snapcraft (launchpad)
Number: #1740882
Type: issue
State: closed
Author: ~p-pisati
Labels: —
Created: 2018-01-02 03:21 PM UTC
Updated: 2021-08-25 09:58 PM UTC
Closed: 2018-02-09 03:59 PM UTC

Current evaluation

⚠️ This summary may be outdated — the issue content or evaluation prompts have changed since this evaluation was made.

Closed without resolution. The snapcraft kernel plugin failure caused by a missing initrd.img-core symlink appears abandoned or superseded by newer versions.

Suggested action: —

No scores available.

Issue body

I'm puzzled by this new "behaviour" of the kernel plugin in snapcraft - it's reproducible in every version i tried (2.35...2.38). $ cat snapcraft.yaml name: kernel version: 4.13.16+ summary: Linux kernel description: The upstream Linux kernel grade: stable confinement: strict type: kernel parts: kernel: plugin: kernel source: . source-type: git kernel-with-firmware: false $ cd linux-vanilla (any recent vanilla linux tree will work, i'm using stable/linux-4.13.y FWIW) $ make defconfig $ snapcraft ... Generating driver initrd for kernel release: 4.13.16+ Parallel unsquashfs: Using 4 processors 2 inodes (2 blocks) to write [===========================================================================================================================================|] 2/2 100% created 0 files created 4 directories created 2 symlinks created 0 devices created 0 fifos ... Traceback (most recent call last): [3252/9137] File "/home/flag/canonical/snapcraft/bin/snapcraft", line 36, in <module> obj=dict(project=snapcraft.ProjectOptions())) File "/usr/lib/python3/dist-packages/click/core.py", line 716, in __call__ return self.main(*args, **kwargs) File "/usr/lib/python3/dist-packages/click/core.py", line 696, in main rv = self.invoke(ctx) File "/usr/lib/python3/dist-packages/click/core.py", line 1037, in invoke return Command.invoke(self, ctx) File "/usr/lib/python3/dist-packages/click/core.py", line 889, in invoke return ctx.invoke(self.callback, **ctx.params) File "/usr/lib/python3/dist-packages/click/core.py", line 534, in invoke return callback(*args, **kwargs) File "/usr/lib/python3/dist-packages/click/decorators.py", line 17, in new_func return f(get_current_context(), *args, **kwargs) File "/home/flag/canonical/snapcraft/snapcraft/cli/__init__.py", line 124, in run ctx.forward(lifecyclecli.commands['snap']) File "/usr/lib/python3/dist-packages/click/core.py", line 552, in forward return self.invoke(cmd, **kwargs) File "/usr/lib/python3/dist-packages/click/core.py", line 534, in invoke return callback(*args, **kwargs) File "/home/flag/canonical/snapcraft/snapcraft/cli/lifecycle.py", line 140, in snap project_options, directory=directory, output=output) File "/home/flag/canonical/snapcraft/snapcraft/internal/lifecycle/_packer.py", line 45, in snap execute('prime', project_options) File "/home/flag/canonical/snapcraft/snapcraft/internal/lifecycle/_runner.py", line 80, in execute _Executor(config, project_options).run(step, part_names) File "/home/flag/canonical/snapcraft/snapcraft/internal/lifecycle/_runner.py", line 175, in run self._run_step(step, part, part_names) File "/home/flag/canonical/snapcraft/snapcraft/internal/lifecycle/_runner.py", line 212, in _run_step getattr(part, step)() File "/home/flag/canonical/snapcraft/snapcraft/internal/pluginhandler/__init__.py", line 330, in build self.plugin.build() File "/home/flag/canonical/snapcraft/snapcraft/plugins/kbuild.py", line 258, in build self.do_install() File "/home/flag/canonical/snapcraft/snapcraft/plugins/kernel.py", line 473, in do_install self._make_initrd() File "/home/flag/canonical/snapcraft/snapcraft/plugins/kernel.py", line 286, in _make_initrd initrd_unpacked_path = self._unpack_generic_initrd() File "/home/flag/canonical/snapcraft/snapcraft/plugins/kernel.py", line 255, in _unpack_generic_initrd mime_type = mime_detector.file(os.path.realpath(tmp_initrd_path)) File "/home/flag/.local/lib/python3.5/site-packages/magic.py", line 134, in file return str(r, 'utf-8') TypeError: coercing to str: need a bytes-like object, NoneType found so i added the following debug patch and snapped again: diff --git a/snapcraft/plugins/kernel.py b/snapcraft/plugins/kernel.py index c1e81e4..e388c2c 100644 --- a/snapcraft/plugins/kernel.py +++ b/snapcraft/plugins/kernel.py @@ -60,6 +60,7 @@ import glob import logging import magic import os +import pty import shutil import subprocess import tempfile @@ -248,6 +249,11 @@ class KernelPlugin(kbuild.KBuildPlugin): mime_detector.load() # Make sure we're getting the mime type of the actual initrd, not # a symbolic link. + logger.info('tmp_initrd_path: {}\n'.format(os.path.realpath(tmp_initrd_path))) + myfile = os.path.realpath(tmp_initrd_path) + if not os.path.exists(myfile): + logger.info('Missing initrd, spwaning a shell') + pty.spawn("/bin/dash") mime_type = mime_detector.file(os.path.realpath(tmp_initrd_path)) if not mime_type: raise RuntimeError( $ snapcraft ... created 0 files created 4 directories created 2 symlinks created 0 devices created 0 fifos tmp_initrd_path: /tmp/tmp27aod6nv/squashfs-root/boot/initrd.img-core Missing initrd, spwaning a shell $ find /tmp/tmp27aod6nv/squashfs-root/ /tmp/tmp27aod6nv/squashfs-root/ /tmp/tmp27aod6nv/squashfs-root/usr /tmp/tmp27aod6nv/squashfs-root/usr/lib /tmp/tmp27aod6nv/squashfs-root/usr/lib/ubuntu-core-generic-initrd /tmp/tmp27aod6nv/squashfs-root/usr/lib/ubuntu-core-generic-initrd/initrd.img-core-0.7.43+ppa23 /tmp/tmp27aod6nv/squashfs-root/usr/lib/ubuntu-core-generic-initrd/initrd.img-core $ ls -la /tmp/tmp27aod6nv/squashfs-root/usr/lib/ubuntu-core-generic-initrd total 8 drwxr-xr-x 2 flag flag 4096 nov 30 18:38 . drwxr-xr-x 3 flag flag 4096 nov 30 18:38 .. lrwxrwxrwx 1 flag flag 29 nov 30 18:37 initrd.img-core -> ../../../boot/initrd.img-core lrwxrwxrwx 1 flag flag 42 nov 30 18:37 initrd.img-core-0.7.43+ppa23 -> ../../../boot/initrd.img-core-0.7.43+ppa23 $ cat /tmp/tmp27aod6nv/squashfs-root/usr/lib/ubuntu-core-generic-initrd/initrd.img-core cat: /tmp/tmp27aod6nv/squashfs-root/usr/lib/ubuntu-core-generic-initrd/initrd.img-core: No such file or directory Manually unsquashing os.snap, there's this: $ unsquashfs -d foobar ./parts/kernel/src/os.snap $ find foobar -name \initrd\* foobar/boot/initrd.img-core-0.7.43+ppa23 foobar/boot/initrd.img-core foobar/lib/systemd/system/initrd-switch-root.service foobar/lib/systemd/system/initrd-parse-etc.service foobar/lib/systemd/system/initrd-fs.target foobar/lib/systemd/system/initrd-root-fs.target foobar/lib/systemd/system/initrd-cleanup.service foobar/lib/systemd/system/initrd-switch-root.target foobar/lib/systemd/system/initrd-udevadm-cleanup-db.service foobar/lib/systemd/system/initrd.target foobar/usr/lib/ubuntu-core-generic-initrd/initrd.img-core-0.7.43+ppa23 foobar/usr/lib/ubuntu-core-generic-initrd/initrd.img-core $ ls -la foobar/usr/lib/ubuntu-core-generic-initrd/initrd.img-core lrwxrwxrwx 1 flag flag 29 nov 30 18:37 foobar/usr/lib/ubuntu-core-generic-initrd/initrd.img-core -> ../../../boot/initrd.img-core $ md5sum foobar/usr/lib/ubuntu-core-generic-initrd/initrd.img-core e4b9d74334b4f40ec07e1ee20c48462b foobar/usr/lib/ubuntu-core-generic-initrd/initrd.img-core Was initrd.img-core moved from usr/lib/ubuntu-core-generic-initrd to boot without updating the kernel plugin?

Evaluation history

Date	Model	Scores	Action	Summary
2026-07-23 03:43 PM UTC	qwen/qwen3.6-35b-a3b	—	—	Closed without resolution. The snapcraft kernel plugin failure caused by a missing initrd.img-core symlink appears abandoned or superseded by newer versions.
2026-07-22 02:14 PM UTC	qwen/qwen3.6-35b-a3b	—	—	A kernel snap build failure caused by a missing initrd.img-core symlink was closed without comments or fixes, indicating abandonment. No resolution or merge details were provided.
2026-07-04 10:29 AM UTC	qwen3.6-35b-a3b-mtp-q6	—	—	Closed without resolution. The initrd.img-core symlink bug in the snapcraft kernel plugin was abandoned due to inactivity, with no fix implemented.

Update history

No update history recorded yet.

Related issues

Issue	Project	State	Summary	Similarity
#1567564 kernel plugin should use initrd from /boot in the os snap, not from /usr/lib	snapcraft (launchpad)	closed	Closed without resolution. The proposal to update the snapcraft kernel plugin to source initrd from /boot instead of /usr/lib was abandoned or superseded by later changes, leaving the legacy duplication in place.	77%
#1627923 kernel plugin initrd packaging fails when kernel modules have common dependencies	snapcraft (launchpad)	closed	Snapcraft kernel plugin initrd packaging failed when shared module dependencies triggered a file exists error. The report was closed without comments or resolution, indicating it was abandoned.	72%