anaconda-iso fails with quay.io/almalinuxorg/almalinux-bootc and librepo=True

[NiklasReisser]

Hi,

I am trying to build an installer image with almalinux.
Almalinux bootc support is officially experimental, and I am new to bootc, so this might be in the wrong place. If so, sorry. Please point out a better place to post the issue.

I build a image based on almalinux-bootc and this template: https://github.com/osbuild/bootc-image-builder#bootc-installer. The image to be installed is based on this example, only that its base is Almalinux: https://gitlab.com/fedora/bootc/examples/-/blob/main/kernel-rt-rpm-ostree/Containerfile?ref_type=heads

I am running Fedora Silverblue in a KVM machine.

The containers, both actual image and installer, build fine. If I base the images on Cent OS Stream 10, the image is created successfully. However this command fails for almalinux:

sudo podman run \
    --rm \
    -it \
    --privileged \
    -v ./config.toml:/config.toml:ro \
    --security-opt label=type:unconfined_t \
    -v ./output:/output -v ./config.toml:/config.toml:ro \
    -v /var/lib/containers/storage:/var/lib/containers/storage \
    quay.io/centos-bootc/bootc-image-builder:latest \
    --type anaconda-iso \
    --use-librepo=True \
    --installer-payload-ref localhost/rt-test \
    localhost/rt-test-installer -v --log-level debug

It gets a bit further with --use-librepo=False , but doesn't finish. I assume the mirror is just out of sync though, the packages really don't exist at time of writing, only up to 8.7p1-48:

source/org.osbuild.curl (org.osbuild.curl): WARNING: failed to download http://mirrors.nz.zappie.host/almalinux/9.7/BaseOS/x86_64/os/Packages/openssh-8.7p1-49.el9_7.alma.1.x86_64.rpm: The requested URL returned error: 404

To be honest, I don't understand why packages must be downloaded at all during the creation. Shouldn't they already be in container images? And the job of the bootc-image-builder is to convert the OCI image into an .iso?

How can I configure the mirror manually for testing?

Please let me know if more information is needed. Thanks for the any support!

Here is the output from the bootc-image-builder:

$ ./build.sh 
[sudo] password for niklas: 
Error: no Containerfile or Dockerfile specified or found in context directory, /var/home/niklas/Projects/bootc: no such file or directory
STEP 1/3: FROM quay.io/almalinuxorg/almalinux-bootc:latest
STEP 2/3: RUN dnf install -y      anaconda      anaconda-install-env-deps      anaconda-dracut      dracut-config-generic      dracut-network      net-tools      squashfs-tools      grub2-efi-x64-cdboot      python3-mako      lorax-templates-*      biosdevname      prefixdevname      && dnf clean all
--> Using cache 292f451c2d5e6a5b103c3bca5f987240e8c9c95d4d392684717e728feeaeb1e6
--> 292f451c2d5e
STEP 3/3: RUN mkdir /var/mnt
--> Using cache d566bf3351e8a6083461a8b3044d1421daec69e228121b5c4f78be46149dba42
COMMIT rt-test-installer
--> d566bf3351e8
Successfully tagged localhost/rt-test-installer:latest
d566bf3351e8a6083461a8b3044d1421daec69e228121b5c4f78be46149dba42
DEBU[0000] Validating environment                       
DEBU[0000] Ensuring environment setup                   
Generating manifest manifest-anaconda-iso.json
Manifest generation step
WARN[0001] Unknown distro almalinux, using default runner 
DEBU[0016] [graphdriver] trying provided driver "overlay" 
DEBU[0016] Cached value indicated that overlay is supported 
DEBU[0016] Cached value indicated that overlay is supported 
DEBU[0016] overlay: test mount indicated that metacopy is not being used 
DEBU[0016] backingFs=btrfs, projectQuotaSupported=false, useNativeDiff=true, usingMetacopy=false 
DEBU[0016] parsed reference into "[overlay@/var/lib/containers/storage+/run/containers/storage]localhost/rt-test-installer:latest" 
DEBU[0016] exporting opaque data as blob "sha256:d566bf3351e8a6083461a8b3044d1421daec69e228121b5c4f78be46149dba42" 
Done generating manifest
Disk image building step
Building manifest-anaconda-iso.json
starting -Pipeline source org.osbuild.containers-storage: e52dba7c092546c9487930f074710a85683bb315f1dc8b16bce4ce0c3f18961d
Build
  root: <host>
Pipeline source org.osbuild.inline: 2a74a4553a001fb79eb2ca1f31f16daae302d17da5878e7f848a2c31cd443119
Build
  root: <host>
Pipeline source org.osbuild.librepo: ea1c9c4092cfaab127cd01aa44047cae4a96139bea9987802a7d6a4086ba1857
Build
  root: <host>
source/org.osbuild.librepo (org.osbuild.librepo): Error downloading Packages/tigervnc-license-1.15.0-6.el9_7.1.noarch.rpm
source/org.osbuild.librepo (org.osbuild.librepo): Error downloading Packages/libwayland-egl-1.21.0-1.el9.x86_64.rpm
source/org.osbuild.librepo (org.osbuild.librepo): Error downloading Packages/plymouth-scripts-0.9.5-7.20210331git1ea1020.el9.x86_64.rpm
source/org.osbuild.librepo (org.osbuild.librepo): Error downloading Packages/fxload-2008_10_13-21.el9.x86_64.rpm
source/org.osbuild.librepo (org.osbuild.librepo): Error downloading Packages/libblockdev-fs-2.28-14.el9_6.x86_64.rpm
source/org.osbuild.librepo (org.osbuild.librepo): Error downloading Packages/harfbuzz-icu-2.7.4-10.el9.x86_64.rpm
...
<many packages>
...
source/org.osbuild.librepo (org.osbuild.librepo): 
source/org.osbuild.librepo (org.osbuild.librepo): (process:242): librepo-WARNING **: 02:00:18.376: Error while removing: No such file or directory
source/org.osbuild.librepo (org.osbuild.librepo): 
source/org.osbuild.librepo (org.osbuild.librepo): (process:242): librepo-WARNING **: 02:00:18.376: Error while removing: No such file or directory
source/org.osbuild.librepo (org.osbuild.librepo): 
source/org.osbuild.librepo (org.osbuild.librepo): (process:242): librepo-WARNING **: 02:00:18.376: Error while removing: No such file or directory
source/org.osbuild.librepo (org.osbuild.librepo): 
source/org.osbuild.librepo (org.osbuild.librepo): (process:242): librepo-WARNING **: 02:00:18.376: Error while removing: No such file or directory
source/org.osbuild.librepo (org.osbuild.librepo): 
source/org.osbuild.librepo (org.osbuild.librepo): (process:242): librepo-WARNING **: 02:00:18.376: Error while removing: No such file or directory
source/org.osbuild.librepo (org.osbuild.librepo): 
source/org.osbuild.librepo (org.osbuild.librepo): (process:242): librepo-WARNING **: 02:00:18.376: Error while removing: No such file or directory
...
<many failed removals, downloads and removals again>
...
Traceback (most recent call last):
  File "/usr/bin/osbuild", line 33, in <module>
    sys.exit(load_entry_point('osbuild==180', 'console_scripts', 'osbuild')())
             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^
  File "/usr/lib/python3.13/site-packages/osbuild/main_cli.py", line 189, in osbuild_cli
    manifest.download(object_store, monitor)
    ~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.13/site-packages/osbuild/pipeline.py", line 581, in download
    raise e
  File "/usr/lib/python3.13/site-packages/osbuild/pipeline.py", line 576, in download
    source.download(mgr, store)
    ~~~~~~~~~~~~~~~^^^^^^^^^^^^
  File "/usr/lib/python3.13/site-packages/osbuild/sources.py", line 41, in download
    reply = client.call("download", args)
  File "/usr/lib/python3.13/site-packages/osbuild/host.py", line 348, in call
    ret, _ = self.call_with_fds(method, args)
             ~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^
  File "/usr/lib/python3.13/site-packages/osbuild/host.py", line 384, in call_with_fds
    raise error
osbuild.host.RemoteError: RuntimeError: Packages/tigervnc-license-1.15.0-6.el9_7.1.noarch.rpm: No more mirrors to try - All mirrors were already tried without success, ... <many packages>
...
   File "/usr/lib/python3.13/site-packages/osbuild/host.py", line 268, in serve
    reply, reply_fds = self._handle_message(msg, fds)
                       ~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^
  File "/usr/lib/python3.13/site-packages/osbuild/host.py", line 301, in _handle_message
    ret, fds = self.dispatch(name, args, fds)
               ~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.13/site-packages/osbuild/sources.py", line 131, in dispatch
    self.fetch_all(args["items"])
    ~~~~~~~~~~~~~~^^^^^^^^^^^^^^^
  File "/usr/lib/osbuild/sources/org.osbuild.librepo", line 269, in fetch_all
    raise RuntimeError(",".join(self.errors))

2026/05/05 02:00:20 error: cannot run osbuild: error running osbuild: exit status 1

[supakeen]

Hey; you're in the right place. The anaconda-iso type is an image type that reads the container you give it and then builds the Anaconda root filesystem out of RPMs from the repositories it finds in the container. This was a historical approach and as such the image type is deprecated. We prefer you use the bootc-generic-iso image type which does as you expect (splat a container onto an ISO).

You can read how to build a container for the ISO (and the requirements it needs to satisfy) and how to embed a payload here: https://github.com/osbuild/image-builder-cli/blob/main/doc/20-advanced/20-bootc/10-isos.md

Let me know if that works for you or if you run into any issues with that approach.

---

As for the librepo things not working correctly when it does fetch packages. I guess it might be related to the dependency solver not handling x86 microarchitectures correctly. I'd prefer to sidestep the issue with the above approach but if we can't we might have to do some further debugging on that.

[NiklasReisser]

Thanks for the fast reply.

The container in this repo's README, quay.io/centos-bootc/bootc-image-builder:latest, does not (yet?) support the generic-iso:

2026/05/06 00:50:38 error: cannot build manifest: cannot detect build types [bootc-generic-iso]: unsupported image type "bootc-generic-iso", valid types are ami, anaconda-iso, bootc-installer, gce, iso, ova, pxe-tar-xz, qcow2, raw, vhd, vmdk

What is the relationship between osbuild/image-builder-cli and osbuild/bootc-image-builder (and where sits bootc-dev/bcvk to-disk, if you happen to know it)?
It appears I have picked the wrong (deprecated? https://github.com/osbuild/image-builder-cli/blob/main/doc/20-advanced/20-bootc/50-migration.md) one and should use image-builder-cli in the future?

[supakeen]

That's a good point, perhaps we should support the bootc-generic-iso image type in bootc-image-builder to ease transition, I'll discuss this with some people today.

We would indeed prefer if you start using image-builder, even if the deprecation timeline is quite long (RHEL-11), see: https://osbuild.org/docs/bootc/deprecation-notice/ for the timeline and reasoning and when we plan to have downstream containers.

I should also actually fill in the page you linked to link to the deprecation documentation and have actual content.

I'm not too familiar with bcvk but as I understand it it partially wraps bootc-image-builder in a vm for some image types.

[NiklasReisser]

That's a good point, perhaps we should support the bootc-generic-iso image type in bootc-image-builder to ease transition, I'll discuss this with some people today.

Well, I basically start fresh, so I can start with the new tool as well. A more visible deprecation notice, maybe in this repo's README.md, would have helped at least me, to be honest.

We would indeed prefer if you start using image-builder, even if the deprecation timeline is quite long (RHEL-11), see: https://osbuild.org/docs/bootc/deprecation-notice/ for the timeline and reasoning and when we plan to have downstream containers.

I know that bootc is quite fresh in general, but I would ideally start with a somewhat stable interface. bootc support in image-builder-cli is marked experimental. How stable do you think it is?

I should also actually fill in the page you linked to link to the deprecation documentation and have actual content.

That would be great, thanks. Even though, as said, luckily, I am not migrating, but starting out fresh.

I'm not too familiar with bcvk but as I understand it it partially wraps bootc-image-builder in a vm for some image types.

Thanks.

My next question, even though this is getting a bit OT, and I am happy to open another thread:
How do these images relate to the generic ISO? Is this also referring to the older tool landscape?
https://osbuild.org/docs/user-guide/introduction/
https://osbuild.org/docs/user-guide/image-descriptions/almalinux_kitten-10/image-installer/

[supakeen]

Well, I basically start fresh, so I can start with the new tool as well. A more visible deprecation notice, maybe in this repo's README.md, would have helped at least me, to be honest.

@jlsherrill this is probably a good idea? Shall I PR this?

I know that bootc is quite fresh in general, but I would ideally start with a somewhat stable interface. bootc support in image-builder-cli is marked experimental. How stable do you think it is?

It's not experimental and that message should've been gone, I guess we've all been reading over it. I PR'ed its removal: osbuild/image-builder-cli#510

My next question, even though this is getting a bit OT, and I am happy to open another thread: How do these images relate to the generic ISO? Is this also referring to the older tool landscape? https://osbuild.org/docs/user-guide/introduction/ https://osbuild.org/docs/user-guide/image-descriptions/almalinux_kitten-10/image-installer/

I'm fine answering. That page is not referring to the older tool landscape but it is referring to package-based systems. In the case of those images there (e.g. image-installer) there are pre-made definitions and repositories embedded in image-builder that can be customized by end-users within limits (or overridden entirely with less limits).

A small, probably irrelevant, note here is that we probably also intend to replace osbuild-composer with image-builder for on-premises users; unifying all of our command-line tooling into a single executable.

---

With bootc-based images this isn't the case and the user has to provide everything inside the container(s) and thus know everything such as regenerating the initramfs to include the appropriate modules, ensuring the bootloader is in the right place, writing the appropriate installer configuration, that sort of stuff.

We do as little as possible in the bootc-generic-iso image type which means we also don't put any guardrails in place. In the end we just take a bunch of files that are expected to exist in the container and mash them onto the ISO in an appropriate format.

[NiklasReisser]

Thanks for the explanation & the quick action regarding the experimental message! I was able to build an image that way, however I am still running into errors when trying to embed a local image to be installed through. I'll create an issue in the actual image-builder repo though, since the actual question here is answered.

With bootc-based images this isn't the case and the user has to provide everything inside the container(s) and thus know everything such as regenerating the initramfs to include the appropriate modules, ensuring the bootloader is in the right place, writing the appropriate installer configuration, that sort of stuff.

Are you referring to that Containerfile: https://github.com/osbuild/image-builder-cli/blob/main/doc/20-advanced/20-bootc/10-isos.md#example-containerfile ?
So, the idea is that e.g. a distro like CentOS uses image-builder in the end to create their own installer images? (As opposed to image-builder knowing how CentOS wants to build a boot.iso?)