rootdev: Only use stat.rdev instead of looking up /sys/block/DEV/dev #12
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
When /dev/mapper/usr is not a symlink to /dev/dm-0 but directly an equal device node, we can't find the /sys/block/DEV/dev entry for it because this is /sys/block/dm-0/dev and we can't device the "dm-0" name. However, we can directly use the device major and minor numbers of the device node through stat and continue with it in any case. Signed-off-by: Kai Lueke <[email protected]>
chewi
approved these changes
Sep 16, 2025
chewi
left a comment
chewi
left a comment
There was a problem hiding this comment.
Nice. I wonder if you can also drop the last remaining use of devt_from_file.
krnowak
approved these changes
Sep 16, 2025
2 tasks
pothos
added a commit
to flatcar/scripts
that referenced
this pull request
Sep 19, 2025
The growth of binaries over time and the inclusion of new features filled the available boot partition space, so that the kernel+initrd almost couldn't fit twice anymore as required for updates. We employed workarounds such as wrapper scripts for ignition, afterburn and other binaries so that they are loaded from /usr. However, this was still not enough and we would have to do the same for (network) kernel modules and firmware. To avoid making this ever more complex we can use a dedicated initrd focused on loading the full initrd from /usr and then this full initrd can use dracut as before and even drop all the workarounds we accumulated. Generate a minimal initrd to use instead of the full bootengine initrd. The bootengine initrd gets stored as squashfs on /usr. The minimal initrd still includes the early_cpio for amd64 microcode updates. We have a fixed list of modules or module directories to include, only focused on loading /usr and any emergency console interaction. This requires also checking for module dependencies to copy over. The busybox, veritysetup, and kmod binaries are needed and get their required libraries resolved and copied over. They are not static and use shared libraries which should be ok for now. The resulting vmlinuz file is 27 MB for amd64, down from ~60 MB, so we have enough room to include more kernel modules and so on for the next years while we also grow the boot partition and wait for users to redeploy until we can rely on a larger boot partition and eventually drop the minimal initrd again. Pulls in flatcar/bootengine#110 for the minimal initrd script and flatcar/seismograph#12 for making the device mapper discovery for the "rootdev" command more reliable. This also requied a backport of a kernel patch from 2017 that exposes the PARTUUID in the /sys uevent file. Co-authored-by: James Le Cuirot <[email protected]> Signed-off-by: Kai Lueke <[email protected]>
pothos
added a commit
to flatcar/scripts
that referenced
this pull request
Sep 19, 2025
The growth of binaries over time and the inclusion of new features filled the available boot partition space, so that the kernel+initrd almost couldn't fit twice anymore as required for updates. We employed workarounds such as wrapper scripts for ignition, afterburn and other binaries so that they are loaded from /usr. However, this was still not enough and we would have to do the same for (network) kernel modules and firmware. To avoid making this ever more complex we can use a dedicated initrd focused on loading the full initrd from /usr and then this full initrd can use dracut as before and even drop all the workarounds we accumulated. Generate a minimal initrd to use instead of the full bootengine initrd. The bootengine initrd gets stored as squashfs on /usr. The minimal initrd still includes the early_cpio for amd64 microcode updates. We have a fixed list of modules or module directories to include, only focused on loading /usr and any emergency console interaction. This requires also checking for module dependencies to copy over. The busybox, veritysetup, and kmod binaries are needed and get their required libraries resolved and copied over. They are not static and use shared libraries which should be ok for now. The resulting vmlinuz file is 27 MB for amd64, down from ~60 MB, so we have enough room to include more kernel modules and so on for the next years while we also grow the boot partition and wait for users to redeploy until we can rely on a larger boot partition and eventually drop the minimal initrd again. Pulls in flatcar/bootengine#110 for the minimal initrd script and flatcar/seismograph#12 for making the device mapper discovery for the "rootdev" command more reliable. This also requied a backport of a kernel patch from 2017 that exposes the PARTUUID in the /sys uevent file. Co-authored-by: James Le Cuirot <[email protected]> Signed-off-by: Kai Lueke <[email protected]>
pothos
added a commit
to flatcar/scripts
that referenced
this pull request
Sep 22, 2025
The growth of binaries over time and the inclusion of new features filled the available boot partition space, so that the kernel+initrd almost couldn't fit twice anymore as required for updates. We employed workarounds such as wrapper scripts for ignition, afterburn and other binaries so that they are loaded from /usr. However, this was still not enough and we would have to do the same for (network) kernel modules and firmware. To avoid making this ever more complex we can use a dedicated initrd focused on loading the full initrd from /usr and then this full initrd can use dracut as before and even drop all the workarounds we accumulated. Generate a minimal initrd to use instead of the full bootengine initrd. The bootengine initrd gets stored as squashfs on /usr. The minimal initrd still includes the early_cpio for amd64 microcode updates. We have a fixed list of modules or module directories to include, only focused on loading /usr and any emergency console interaction. This requires also checking for module dependencies to copy over. The busybox, veritysetup, and kmod binaries are needed and get their required libraries resolved and copied over. They are not static and use shared libraries which should be ok for now. The resulting vmlinuz file is 27 MB for amd64, down from ~60 MB, so we have enough room to include more kernel modules and so on for the next years while we also grow the boot partition and wait for users to redeploy until we can rely on a larger boot partition and eventually drop the minimal initrd again. Pulls in flatcar/bootengine#110 for the minimal initrd script and flatcar/seismograph#12 for making the device mapper discovery for the "rootdev" command more reliable. This also requied a backport of a kernel patch from 2017 that exposes the PARTUUID in the /sys uevent file. Co-authored-by: James Le Cuirot <[email protected]> Signed-off-by: Kai Lueke <[email protected]>
pothos
added a commit
to flatcar/scripts
that referenced
this pull request
Sep 22, 2025
The growth of binaries over time and the inclusion of new features filled the available boot partition space, so that the kernel+initrd almost couldn't fit twice anymore as required for updates. We employed workarounds such as wrapper scripts for ignition, afterburn and other binaries so that they are loaded from /usr. However, this was still not enough and we would have to do the same for (network) kernel modules and firmware. To avoid making this ever more complex we can use a dedicated initrd focused on loading the full initrd from /usr and then this full initrd can use dracut as before and even drop all the workarounds we accumulated. Generate a minimal initrd to use instead of the full bootengine initrd. The bootengine initrd gets stored as squashfs on /usr. The minimal initrd still includes the early_cpio for amd64 microcode updates. We have a fixed list of modules or module directories to include, only focused on loading /usr and any emergency console interaction. This requires also checking for module dependencies to copy over. The busybox, veritysetup, and kmod binaries are needed and get their required libraries resolved and copied over. They are not static and use shared libraries which should be ok for now. The resulting vmlinuz file is 27 MB for amd64, down from ~60 MB, so we have enough room to include more kernel modules and so on for the next years while we also grow the boot partition and wait for users to redeploy until we can rely on a larger boot partition and eventually drop the minimal initrd again. Pulls in flatcar/bootengine#110 for the minimal initrd script and flatcar/seismograph#12 for making the device mapper discovery for the "rootdev" command more reliable. This also requied a backport of a kernel patch from 2017 that exposes the PARTUUID in the /sys uevent file. Co-authored-by: James Le Cuirot <[email protected]> Signed-off-by: Kai Lueke <[email protected]>
pothos
added a commit
to flatcar/scripts
that referenced
this pull request
Sep 22, 2025
The growth of binaries over time and the inclusion of new features filled the available boot partition space, so that the kernel+initrd almost couldn't fit twice anymore as required for updates. We employed workarounds such as wrapper scripts for ignition, afterburn and other binaries so that they are loaded from /usr. However, this was still not enough and we would have to do the same for (network) kernel modules and firmware. To avoid making this ever more complex we can use a dedicated initrd focused on loading the full initrd from /usr and then this full initrd can use dracut as before and even drop all the workarounds we accumulated. Generate a minimal initrd to use instead of the full bootengine initrd. The bootengine initrd gets stored as squashfs on /usr. The minimal initrd still includes the early_cpio for amd64 microcode updates. We have a fixed list of modules or module directories to include, only focused on loading /usr and any emergency console interaction. This requires also checking for module dependencies to copy over. The busybox, veritysetup, and kmod binaries are needed and get their required libraries resolved and copied over. They are not static and use shared libraries which should be ok for now. The resulting vmlinuz file is 27 MB for amd64, down from ~60 MB, so we have enough room to include more kernel modules and so on for the next years while we also grow the boot partition and wait for users to redeploy until we can rely on a larger boot partition and eventually drop the minimal initrd again. Pulls in flatcar/bootengine#110 for the minimal initrd script and flatcar/seismograph#12 for making the device mapper discovery for the "rootdev" command more reliable. This also requied a backport of a kernel patch from 2017 that exposes the PARTUUID in the /sys uevent file. Co-authored-by: James Le Cuirot <[email protected]> Signed-off-by: Kai Lueke <[email protected]>
pothos
added a commit
to flatcar/scripts
that referenced
this pull request
Sep 23, 2025
The growth of binaries over time and the inclusion of new features filled the available boot partition space, so that the kernel+initrd almost couldn't fit twice anymore as required for updates. We employed workarounds such as wrapper scripts for ignition, afterburn and other binaries so that they are loaded from /usr. However, this was still not enough and we would have to do the same for (network) kernel modules and firmware. To avoid making this ever more complex we can use a dedicated initrd focused on loading the full initrd from /usr and then this full initrd can use dracut as before and even drop all the workarounds we accumulated. Generate a minimal initrd to use instead of the full bootengine initrd. The bootengine initrd gets stored as squashfs on /usr. The minimal initrd still includes the early_cpio for amd64 microcode updates. We have a fixed list of modules or module directories to include, only focused on loading /usr and any emergency console interaction. This requires also checking for module dependencies to copy over. The busybox, veritysetup, and kmod binaries are needed and get their required libraries resolved and copied over. They are not static and use shared libraries which should be ok for now. The resulting vmlinuz file is 27 MB for amd64, down from ~60 MB, so we have enough room to include more kernel modules and so on for the next years while we also grow the boot partition and wait for users to redeploy until we can rely on a larger boot partition and eventually drop the minimal initrd again. Pulls in flatcar/bootengine#110 for the minimal initrd script and flatcar/seismograph#12 for making the device mapper discovery for the "rootdev" command more reliable. This also requied a backport of a kernel patch from 2017 that exposes the PARTUUID in the /sys uevent file. Co-authored-by: James Le Cuirot <[email protected]> Signed-off-by: Kai Lueke <[email protected]>
pothos
added a commit
to flatcar/scripts
that referenced
this pull request
Sep 30, 2025
The growth of binaries over time and the inclusion of new features filled the available boot partition space, so that the kernel+initrd almost couldn't fit twice anymore as required for updates. We employed workarounds such as wrapper scripts for ignition, afterburn and other binaries so that they are loaded from /usr. However, this was still not enough and we would have to do the same for (network) kernel modules and firmware. To avoid making this ever more complex we can use a dedicated initrd focused on loading the full initrd from /usr and then this full initrd can use dracut as before and even drop all the workarounds we accumulated. Generate a minimal initrd to use instead of the full bootengine initrd. The bootengine initrd gets stored as squashfs on /usr. The minimal initrd still includes the early_cpio for amd64 microcode updates. We have a fixed list of modules or module directories to include, only focused on loading /usr and any emergency console interaction. This requires also checking for module dependencies to copy over. The busybox, veritysetup, and kmod binaries are needed and get their required libraries resolved and copied over. They are not static and use shared libraries which should be ok for now. The resulting vmlinuz file is 27 MB for amd64, down from ~60 MB, so we have enough room to include more kernel modules and so on for the next years while we also grow the boot partition and wait for users to redeploy until we can rely on a larger boot partition and eventually drop the minimal initrd again. Pulls in flatcar/bootengine#110 for the minimal initrd script and flatcar/seismograph#12 for making the device mapper discovery for the "rootdev" command more reliable. This also requied a backport of a kernel patch from 2017 that exposes the PARTUUID in the /sys uevent file. Co-authored-by: James Le Cuirot <[email protected]> Signed-off-by: Kai Lueke <[email protected]>
pothos
added a commit
to flatcar/scripts
that referenced
this pull request
Sep 30, 2025
The growth of binaries over time and the inclusion of new features filled the available boot partition space, so that the kernel+initrd almost couldn't fit twice anymore as required for updates. We employed workarounds such as wrapper scripts for ignition, afterburn and other binaries so that they are loaded from /usr. However, this was still not enough and we would have to do the same for (network) kernel modules and firmware. To avoid making this ever more complex we can use a dedicated initrd focused on loading the full initrd from /usr and then this full initrd can use dracut as before and even drop all the workarounds we accumulated. Generate a minimal initrd to use instead of the full bootengine initrd. The bootengine initrd gets stored as squashfs on /usr. The minimal initrd still includes the early_cpio for amd64 microcode updates. We have a fixed list of modules or module directories to include, only focused on loading /usr and any emergency console interaction. This requires also checking for module dependencies to copy over. The busybox, veritysetup, and kmod binaries are needed and get their required libraries resolved and copied over. They are not static and use shared libraries which should be ok for now. The resulting vmlinuz file is 27 MB for amd64, down from ~60 MB, so we have enough room to include more kernel modules and so on for the next years while we also grow the boot partition and wait for users to redeploy until we can rely on a larger boot partition and eventually drop the minimal initrd again. Pulls in flatcar/bootengine#110 for the minimal initrd script and flatcar/seismograph#12 for making the device mapper discovery for the "rootdev" command more reliable. This also requied a backport of a kernel patch from 2017 that exposes the PARTUUID in the /sys uevent file. Co-authored-by: James Le Cuirot <[email protected]> Signed-off-by: Kai Lueke <[email protected]>
pothos
added a commit
to flatcar/scripts
that referenced
this pull request
Sep 30, 2025
The growth of binaries over time and the inclusion of new features filled the available boot partition space, so that the kernel+initrd almost couldn't fit twice anymore as required for updates. We employed workarounds such as wrapper scripts for ignition, afterburn and other binaries so that they are loaded from /usr. However, this was still not enough and we would have to do the same for (network) kernel modules and firmware. To avoid making this ever more complex we can use a dedicated initrd focused on loading the full initrd from /usr and then this full initrd can use dracut as before and even drop all the workarounds we accumulated. Generate a minimal initrd to use instead of the full bootengine initrd. The bootengine initrd gets stored as squashfs on /usr. The minimal initrd still includes the early_cpio for amd64 microcode updates. We have a fixed list of modules or module directories to include, only focused on loading /usr and any emergency console interaction. This requires also checking for module dependencies to copy over. The busybox, veritysetup, and kmod binaries are needed and get their required libraries resolved and copied over. They are not static and use shared libraries which should be ok for now. The resulting vmlinuz file is 27 MB for amd64, down from ~60 MB, so we have enough room to include more kernel modules and so on for the next years while we also grow the boot partition and wait for users to redeploy until we can rely on a larger boot partition and eventually drop the minimal initrd again. Pulls in flatcar/bootengine#110 for the minimal initrd script and flatcar/seismograph#12 for making the device mapper discovery for the "rootdev" command more reliable. This also requied a backport of a kernel patch from 2017 that exposes the PARTUUID in the /sys uevent file. Co-authored-by: James Le Cuirot <[email protected]> Signed-off-by: Kai Lueke <[email protected]>
pothos
added a commit
to flatcar/scripts
that referenced
this pull request
Sep 30, 2025
The growth of binaries over time and the inclusion of new features filled the available boot partition space, so that the kernel+initrd almost couldn't fit twice anymore as required for updates. We employed workarounds such as wrapper scripts for ignition, afterburn and other binaries so that they are loaded from /usr. However, this was still not enough and we would have to do the same for (network) kernel modules and firmware. To avoid making this ever more complex we can use a dedicated initrd focused on loading the full initrd from /usr and then this full initrd can use dracut as before and even drop all the workarounds we accumulated. Generate a minimal initrd to use instead of the full bootengine initrd. The bootengine initrd gets stored as squashfs on /usr. The minimal initrd still includes the early_cpio for amd64 microcode updates. We have a fixed list of modules or module directories to include, only focused on loading /usr and any emergency console interaction. This requires also checking for module dependencies to copy over. The busybox, veritysetup, and kmod binaries are needed and get their required libraries resolved and copied over. They are not static and use shared libraries which should be ok for now. The resulting vmlinuz file is 27 MB for amd64, down from ~60 MB, so we have enough room to include more kernel modules and so on for the next years while we also grow the boot partition and wait for users to redeploy until we can rely on a larger boot partition and eventually drop the minimal initrd again. Pulls in flatcar/bootengine#110 for the minimal initrd script and flatcar/seismograph#12 for making the device mapper discovery for the "rootdev" command more reliable. This also requied a backport of a kernel patch from 2017 that exposes the PARTUUID in the /sys uevent file. Co-authored-by: James Le Cuirot <[email protected]> Signed-off-by: Kai Lueke <[email protected]>
pothos
added a commit
to flatcar/scripts
that referenced
this pull request
Oct 7, 2025
The growth of binaries over time and the inclusion of new features filled the available boot partition space, so that the kernel+initrd almost couldn't fit twice anymore as required for updates. We employed workarounds such as wrapper scripts for ignition, afterburn and other binaries so that they are loaded from /usr. However, this was still not enough and we would have to do the same for (network) kernel modules and firmware. To avoid making this ever more complex we can use a dedicated initrd focused on loading the full initrd from /usr and then this full initrd can use dracut as before and even drop all the workarounds we accumulated. Generate a minimal initrd to use instead of the full bootengine initrd. The bootengine initrd gets stored as squashfs on /usr. The minimal initrd still includes the early_cpio for amd64 microcode updates. We have a fixed list of modules or module directories to include, only focused on loading /usr and any emergency console interaction. This requires also checking for module dependencies to copy over. The busybox, veritysetup, and kmod binaries are needed and get their required libraries resolved and copied over. They are not static and use shared libraries which should be ok for now. The resulting vmlinuz file is 27 MB for amd64, down from ~60 MB, so we have enough room to include more kernel modules and so on for the next years while we also grow the boot partition and wait for users to redeploy until we can rely on a larger boot partition and eventually drop the minimal initrd again. Pulls in flatcar/bootengine#110 for the minimal initrd script and flatcar/seismograph#12 for making the device mapper discovery for the "rootdev" command more reliable. This also requied a backport of a kernel patch from 2017 that exposes the PARTUUID in the /sys uevent file. Co-authored-by: James Le Cuirot <[email protected]> Signed-off-by: Kai Lueke <[email protected]>
pothos
added a commit
to flatcar/scripts
that referenced
this pull request
Oct 7, 2025
The growth of binaries over time and the inclusion of new features filled the available boot partition space, so that the kernel+initrd almost couldn't fit twice anymore as required for updates. We employed workarounds such as wrapper scripts for ignition, afterburn and other binaries so that they are loaded from /usr. However, this was still not enough and we would have to do the same for (network) kernel modules and firmware. To avoid making this ever more complex we can use a dedicated initrd focused on loading the full initrd from /usr and then this full initrd can use dracut as before and even drop all the workarounds we accumulated. Generate a minimal initrd to use instead of the full bootengine initrd. The bootengine initrd gets stored as squashfs on /usr. The minimal initrd still includes the early_cpio for amd64 microcode updates. We have a fixed list of modules or module directories to include, only focused on loading /usr and any emergency console interaction. This requires also checking for module dependencies to copy over. The busybox, veritysetup, and kmod binaries are needed and get their required libraries resolved and copied over. They are not static and use shared libraries which should be ok for now. The resulting vmlinuz file is 27 MB for amd64, down from ~60 MB, so we have enough room to include more kernel modules and so on for the next years while we also grow the boot partition and wait for users to redeploy until we can rely on a larger boot partition and eventually drop the minimal initrd again. Pulls in flatcar/bootengine#110 for the minimal initrd script and flatcar/seismograph#12 for making the device mapper discovery for the "rootdev" command more reliable. This also requied a backport of a kernel patch from 2017 that exposes the PARTUUID in the /sys uevent file. Co-authored-by: James Le Cuirot <[email protected]> Signed-off-by: Kai Lueke <[email protected]>
pothos
added a commit
to flatcar/scripts
that referenced
this pull request
Oct 7, 2025
The growth of binaries over time and the inclusion of new features filled the available boot partition space, so that the kernel+initrd almost couldn't fit twice anymore as required for updates. We employed workarounds such as wrapper scripts for ignition, afterburn and other binaries so that they are loaded from /usr. However, this was still not enough and we would have to do the same for (network) kernel modules and firmware. To avoid making this ever more complex we can use a dedicated initrd focused on loading the full initrd from /usr and then this full initrd can use dracut as before and even drop all the workarounds we accumulated. Generate a minimal initrd to use instead of the full bootengine initrd. The bootengine initrd gets stored as squashfs on /usr. The minimal initrd still includes the early_cpio for amd64 microcode updates. We have a fixed list of modules or module directories to include, only focused on loading /usr and any emergency console interaction. This requires also checking for module dependencies to copy over. The busybox, veritysetup, and kmod binaries are needed and get their required libraries resolved and copied over. They are not static and use shared libraries which should be ok for now. The resulting vmlinuz file is 27 MB for amd64, down from ~60 MB, so we have enough room to include more kernel modules and so on for the next years while we also grow the boot partition and wait for users to redeploy until we can rely on a larger boot partition and eventually drop the minimal initrd again. Pulls in flatcar/bootengine#110 for the minimal initrd script and flatcar/seismograph#12 for making the device mapper discovery for the "rootdev" command more reliable. This also requied a backport of a kernel patch from 2017 that exposes the PARTUUID in the /sys uevent file. Co-authored-by: James Le Cuirot <[email protected]> Signed-off-by: Kai Lueke <[email protected]>
pothos
added a commit
to flatcar/scripts
that referenced
this pull request
Oct 7, 2025
The growth of binaries over time and the inclusion of new features filled the available boot partition space, so that the kernel+initrd almost couldn't fit twice anymore as required for updates. We employed workarounds such as wrapper scripts for ignition, afterburn and other binaries so that they are loaded from /usr. However, this was still not enough and we would have to do the same for (network) kernel modules and firmware. To avoid making this ever more complex we can use a dedicated initrd focused on loading the full initrd from /usr and then this full initrd can use dracut as before and even drop all the workarounds we accumulated. Generate a minimal initrd to use instead of the full bootengine initrd. The bootengine initrd gets stored as squashfs on /usr. The minimal initrd still includes the early_cpio for amd64 microcode updates. We have a fixed list of modules or module directories to include, only focused on loading /usr and any emergency console interaction. This requires also checking for module dependencies to copy over. The busybox, veritysetup, and kmod binaries are needed and get their required libraries resolved and copied over. They are not static and use shared libraries which should be ok for now. The resulting vmlinuz file is 27 MB for amd64, down from ~60 MB, so we have enough room to include more kernel modules and so on for the next years while we also grow the boot partition and wait for users to redeploy until we can rely on a larger boot partition and eventually drop the minimal initrd again. Pulls in flatcar/bootengine#110 for the minimal initrd script and flatcar/seismograph#12 for making the device mapper discovery for the "rootdev" command more reliable. This also requied a backport of a kernel patch from 2017 that exposes the PARTUUID in the /sys uevent file. Co-authored-by: James Le Cuirot <[email protected]> Signed-off-by: Kai Lueke <[email protected]>
pothos
added a commit
to flatcar/scripts
that referenced
this pull request
Oct 7, 2025
The growth of binaries over time and the inclusion of new features filled the available boot partition space, so that the kernel+initrd almost couldn't fit twice anymore as required for updates. We employed workarounds such as wrapper scripts for ignition, afterburn and other binaries so that they are loaded from /usr. However, this was still not enough and we would have to do the same for (network) kernel modules and firmware. To avoid making this ever more complex we can use a dedicated initrd focused on loading the full initrd from /usr and then this full initrd can use dracut as before and even drop all the workarounds we accumulated. Generate a minimal initrd to use instead of the full bootengine initrd. The bootengine initrd gets stored as squashfs on /usr. The minimal initrd still includes the early_cpio for amd64 microcode updates. We have a fixed list of modules or module directories to include, only focused on loading /usr and any emergency console interaction. This requires also checking for module dependencies to copy over. The busybox, veritysetup, and kmod binaries are needed and get their required libraries resolved and copied over. They are not static and use shared libraries which should be ok for now. The resulting vmlinuz file is 27 MB for amd64, down from ~60 MB, so we have enough room to include more kernel modules and so on for the next years while we also grow the boot partition and wait for users to redeploy until we can rely on a larger boot partition and eventually drop the minimal initrd again. Pulls in flatcar/bootengine#110 for the minimal initrd script and flatcar/seismograph#12 for making the device mapper discovery for the "rootdev" command more reliable. This also requied a backport of a kernel patch from 2017 that exposes the PARTUUID in the /sys uevent file. Co-authored-by: James Le Cuirot <[email protected]> Signed-off-by: Kai Lueke <[email protected]>
pothos
added a commit
to flatcar/scripts
that referenced
this pull request
Oct 7, 2025
The growth of binaries over time and the inclusion of new features filled the available boot partition space, so that the kernel+initrd almost couldn't fit twice anymore as required for updates. We employed workarounds such as wrapper scripts for ignition, afterburn and other binaries so that they are loaded from /usr. However, this was still not enough and we would have to do the same for (network) kernel modules and firmware. To avoid making this ever more complex we can use a dedicated initrd focused on loading the full initrd from /usr and then this full initrd can use dracut as before and even drop all the workarounds we accumulated. Generate a minimal initrd to use instead of the full bootengine initrd. The bootengine initrd gets stored as squashfs on /usr. The minimal initrd still includes the early_cpio for amd64 microcode updates. We have a fixed list of modules or module directories to include, only focused on loading /usr and any emergency console interaction. This requires also checking for module dependencies to copy over. The busybox, veritysetup, and kmod binaries are needed and get their required libraries resolved and copied over. They are not static and use shared libraries which should be ok for now. The resulting vmlinuz file is 27 MB for amd64, down from ~60 MB, so we have enough room to include more kernel modules and so on for the next years while we also grow the boot partition and wait for users to redeploy until we can rely on a larger boot partition and eventually drop the minimal initrd again. Pulls in flatcar/bootengine#110 for the minimal initrd script and flatcar/seismograph#12 for making the device mapper discovery for the "rootdev" command more reliable. This also requied a backport of a kernel patch from 2017 that exposes the PARTUUID in the /sys uevent file. Co-authored-by: James Le Cuirot <[email protected]> Signed-off-by: Kai Lueke <[email protected]>
pothos
added a commit
to flatcar/scripts
that referenced
this pull request
Oct 7, 2025
The growth of binaries over time and the inclusion of new features filled the available boot partition space, so that the kernel+initrd almost couldn't fit twice anymore as required for updates. We employed workarounds such as wrapper scripts for ignition, afterburn and other binaries so that they are loaded from /usr. However, this was still not enough and we would have to do the same for (network) kernel modules and firmware. To avoid making this ever more complex we can use a dedicated initrd focused on loading the full initrd from /usr and then this full initrd can use dracut as before and even drop all the workarounds we accumulated. Generate a minimal initrd to use instead of the full bootengine initrd. The bootengine initrd gets stored as squashfs on /usr. The minimal initrd still includes the early_cpio for amd64 microcode updates. We have a fixed list of modules or module directories to include, only focused on loading /usr and any emergency console interaction. This requires also checking for module dependencies to copy over. The busybox, veritysetup, and kmod binaries are needed and get their required libraries resolved and copied over. They are not static and use shared libraries which should be ok for now. The resulting vmlinuz file is 27 MB for amd64, down from ~60 MB, so we have enough room to include more kernel modules and so on for the next years while we also grow the boot partition and wait for users to redeploy until we can rely on a larger boot partition and eventually drop the minimal initrd again. Pulls in flatcar/bootengine#110 for the minimal initrd script and flatcar/seismograph#12 for making the device mapper discovery for the "rootdev" command more reliable. This also requied a backport of a kernel patch from 2017 that exposes the PARTUUID in the /sys uevent file. Co-authored-by: James Le Cuirot <[email protected]> Signed-off-by: Kai Lueke <[email protected]>
pothos
added a commit
to flatcar/scripts
that referenced
this pull request
Oct 7, 2025
The growth of binaries over time and the inclusion of new features filled the available boot partition space, so that the kernel+initrd almost couldn't fit twice anymore as required for updates. We employed workarounds such as wrapper scripts for ignition, afterburn and other binaries so that they are loaded from /usr. However, this was still not enough and we would have to do the same for (network) kernel modules and firmware. To avoid making this ever more complex we can use a dedicated initrd focused on loading the full initrd from /usr and then this full initrd can use dracut as before and even drop all the workarounds we accumulated. Generate a minimal initrd to use instead of the full bootengine initrd. The bootengine initrd gets stored as squashfs on /usr. The minimal initrd still includes the early_cpio for amd64 microcode updates. We have a fixed list of modules or module directories to include, only focused on loading /usr and any emergency console interaction. This requires also checking for module dependencies to copy over. The busybox, veritysetup, and kmod binaries are needed and get their required libraries resolved and copied over. They are not static and use shared libraries which should be ok for now. The resulting vmlinuz file is 27 MB for amd64, down from ~60 MB, so we have enough room to include more kernel modules and so on for the next years while we also grow the boot partition and wait for users to redeploy until we can rely on a larger boot partition and eventually drop the minimal initrd again. Pulls in flatcar/bootengine#110 for the minimal initrd script and flatcar/seismograph#12 for making the device mapper discovery for the "rootdev" command more reliable. This also requied a backport of a kernel patch from 2017 that exposes the PARTUUID in the /sys uevent file. Co-authored-by: James Le Cuirot <[email protected]> Signed-off-by: Kai Lueke <[email protected]>
pothos
added a commit
to flatcar/scripts
that referenced
this pull request
Oct 7, 2025
The growth of binaries over time and the inclusion of new features filled the available boot partition space, so that the kernel+initrd almost couldn't fit twice anymore as required for updates. We employed workarounds such as wrapper scripts for ignition, afterburn and other binaries so that they are loaded from /usr. However, this was still not enough and we would have to do the same for (network) kernel modules and firmware. To avoid making this ever more complex we can use a dedicated initrd focused on loading the full initrd from /usr and then this full initrd can use dracut as before and even drop all the workarounds we accumulated. Generate a minimal initrd to use instead of the full bootengine initrd. The bootengine initrd gets stored as squashfs on /usr. The minimal initrd still includes the early_cpio for amd64 microcode updates. We have a fixed list of modules or module directories to include, only focused on loading /usr and any emergency console interaction. This requires also checking for module dependencies to copy over. The busybox, veritysetup, and kmod binaries are needed and get their required libraries resolved and copied over. They are not static and use shared libraries which should be ok for now. The resulting vmlinuz file is 27 MB for amd64, down from ~60 MB, so we have enough room to include more kernel modules and so on for the next years while we also grow the boot partition and wait for users to redeploy until we can rely on a larger boot partition and eventually drop the minimal initrd again. Pulls in flatcar/bootengine#110 for the minimal initrd script and flatcar/seismograph#12 for making the device mapper discovery for the "rootdev" command more reliable. This also requied a backport of a kernel patch from 2017 that exposes the PARTUUID in the /sys uevent file. Co-authored-by: James Le Cuirot <[email protected]> Signed-off-by: Kai Lueke <[email protected]>
pothos
added a commit
to flatcar/scripts
that referenced
this pull request
Oct 7, 2025
The growth of binaries over time and the inclusion of new features filled the available boot partition space, so that the kernel+initrd almost couldn't fit twice anymore as required for updates. We employed workarounds such as wrapper scripts for ignition, afterburn and other binaries so that they are loaded from /usr. However, this was still not enough and we would have to do the same for (network) kernel modules and firmware. To avoid making this ever more complex we can use a dedicated initrd focused on loading the full initrd from /usr and then this full initrd can use dracut as before and even drop all the workarounds we accumulated. Generate a minimal initrd to use instead of the full bootengine initrd. The bootengine initrd gets stored as squashfs on /usr. The minimal initrd still includes the early_cpio for amd64 microcode updates. We have a fixed list of modules or module directories to include, only focused on loading /usr and any emergency console interaction. This requires also checking for module dependencies to copy over. The busybox, veritysetup, and kmod binaries are needed and get their required libraries resolved and copied over. They are not static and use shared libraries which should be ok for now. The resulting vmlinuz file is 27 MB for amd64, down from ~60 MB, so we have enough room to include more kernel modules and so on for the next years while we also grow the boot partition and wait for users to redeploy until we can rely on a larger boot partition and eventually drop the minimal initrd again. Pulls in flatcar/bootengine#110 for the minimal initrd script and flatcar/seismograph#12 for making the device mapper discovery for the "rootdev" command more reliable. This also requied a backport of a kernel patch from 2017 that exposes the PARTUUID in the /sys uevent file. Co-authored-by: James Le Cuirot <[email protected]> Signed-off-by: Kai Lueke <[email protected]>
pothos
added a commit
to flatcar/scripts
that referenced
this pull request
Oct 7, 2025
The growth of binaries over time and the inclusion of new features filled the available boot partition space, so that the kernel+initrd almost couldn't fit twice anymore as required for updates. We employed workarounds such as wrapper scripts for ignition, afterburn and other binaries so that they are loaded from /usr. However, this was still not enough and we would have to do the same for (network) kernel modules and firmware. To avoid making this ever more complex we can use a dedicated initrd focused on loading the full initrd from /usr and then this full initrd can use dracut as before and even drop all the workarounds we accumulated. Generate a minimal initrd to use instead of the full bootengine initrd. The bootengine initrd gets stored as squashfs on /usr. The minimal initrd still includes the early_cpio for amd64 microcode updates. We have a fixed list of modules or module directories to include, only focused on loading /usr and any emergency console interaction. This requires also checking for module dependencies to copy over. The busybox, veritysetup, and kmod binaries are needed and get their required libraries resolved and copied over. They are not static and use shared libraries which should be ok for now. The resulting vmlinuz file is 27 MB for amd64, down from ~60 MB, so we have enough room to include more kernel modules and so on for the next years while we also grow the boot partition and wait for users to redeploy until we can rely on a larger boot partition and eventually drop the minimal initrd again. Pulls in flatcar/bootengine#110 for the minimal initrd script and flatcar/seismograph#12 for making the device mapper discovery for the "rootdev" command more reliable. This also requied a backport of a kernel patch from 2017 that exposes the PARTUUID in the /sys uevent file. Co-authored-by: James Le Cuirot <[email protected]> Signed-off-by: Kai Lueke <[email protected]>
pothos
added a commit
to flatcar/scripts
that referenced
this pull request
Oct 8, 2025
The growth of binaries over time and the inclusion of new features filled the available boot partition space, so that the kernel+initrd almost couldn't fit twice anymore as required for updates. We employed workarounds such as wrapper scripts for ignition, afterburn and other binaries so that they are loaded from /usr. However, this was still not enough and we would have to do the same for (network) kernel modules and firmware. To avoid making this ever more complex we can use a dedicated initrd focused on loading the full initrd from /usr and then this full initrd can use dracut as before and even drop all the workarounds we accumulated. Generate a minimal initrd to use instead of the full bootengine initrd. The bootengine initrd gets stored as squashfs on /usr. The minimal initrd still includes the early_cpio for amd64 microcode updates. We have a fixed list of modules or module directories to include, only focused on loading /usr and any emergency console interaction. This requires also checking for module dependencies to copy over. The busybox, veritysetup, and kmod binaries are needed and get their required libraries resolved and copied over. They are not static and use shared libraries which should be ok for now. The resulting vmlinuz file is 27 MB for amd64, down from ~60 MB, so we have enough room to include more kernel modules and so on for the next years while we also grow the boot partition and wait for users to redeploy until we can rely on a larger boot partition and eventually drop the minimal initrd again. Pulls in flatcar/bootengine#110 for the minimal initrd script and flatcar/seismograph#12 for making the device mapper discovery for the "rootdev" command more reliable. This also requied a backport of a kernel patch from 2017 that exposes the PARTUUID in the /sys uevent file. Co-authored-by: James Le Cuirot <[email protected]> Signed-off-by: Kai Lueke <[email protected]>
pothos
added a commit
to flatcar/scripts
that referenced
this pull request
Oct 8, 2025
The growth of binaries over time and the inclusion of new features filled the available boot partition space, so that the kernel+initrd almost couldn't fit twice anymore as required for updates. We employed workarounds such as wrapper scripts for ignition, afterburn and other binaries so that they are loaded from /usr. However, this was still not enough and we would have to do the same for (network) kernel modules and firmware. To avoid making this ever more complex we can use a dedicated initrd focused on loading the full initrd from /usr and then this full initrd can use dracut as before and even drop all the workarounds we accumulated. Generate a minimal initrd to use instead of the full bootengine initrd. The bootengine initrd gets stored as squashfs on /usr. The minimal initrd still includes the early_cpio for amd64 microcode updates. We have a fixed list of modules or module directories to include, only focused on loading /usr and any emergency console interaction. This requires also checking for module dependencies to copy over. The busybox, veritysetup, and kmod binaries are needed and get their required libraries resolved and copied over. They are not static and use shared libraries which should be ok for now. The resulting vmlinuz file is 27 MB for amd64, down from ~60 MB, so we have enough room to include more kernel modules and so on for the next years while we also grow the boot partition and wait for users to redeploy until we can rely on a larger boot partition and eventually drop the minimal initrd again. Pulls in flatcar/bootengine#110 for the minimal initrd script and flatcar/seismograph#12 for making the device mapper discovery for the "rootdev" command more reliable. This also requied a backport of a kernel patch from 2017 that exposes the PARTUUID in the /sys uevent file. Co-authored-by: James Le Cuirot <[email protected]> Signed-off-by: Kai Lueke <[email protected]>
pothos
added a commit
to flatcar/scripts
that referenced
this pull request
Oct 9, 2025
The growth of binaries over time and the inclusion of new features filled the available boot partition space, so that the kernel+initrd almost couldn't fit twice anymore as required for updates. We employed workarounds such as wrapper scripts for ignition, afterburn and other binaries so that they are loaded from /usr. However, this was still not enough and we would have to do the same for (network) kernel modules and firmware. To avoid making this ever more complex we can use a dedicated initrd focused on loading the full initrd from /usr and then this full initrd can use dracut as before and even drop all the workarounds we accumulated. Generate a minimal initrd to use instead of the full bootengine initrd. The bootengine initrd gets stored as squashfs on /usr. The minimal initrd still includes the early_cpio for amd64 microcode updates. We have a fixed list of modules or module directories to include, only focused on loading /usr and any emergency console interaction. This requires also checking for module dependencies to copy over. The busybox, veritysetup, and kmod binaries are needed and get their required libraries resolved and copied over. They are not static and use shared libraries which should be ok for now. The resulting vmlinuz file is 27 MB for amd64, down from ~60 MB, so we have enough room to include more kernel modules and so on for the next years while we also grow the boot partition and wait for users to redeploy until we can rely on a larger boot partition and eventually drop the minimal initrd again. Pulls in flatcar/bootengine#110 for the minimal initrd script and flatcar/seismograph#12 for making the device mapper discovery for the "rootdev" command more reliable. This also requied a backport of a kernel patch from 2017 that exposes the PARTUUID in the /sys uevent file. Co-authored-by: James Le Cuirot <[email protected]> Signed-off-by: Kai Lueke <[email protected]>
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
When /dev/mapper/usr is not a symlink to /dev/dm-0 but directly an equal device node, we can't find the /sys/block/DEV/dev entry for it because this is /sys/block/dm-0/dev and we can't device the "dm-0" name. However, we can directly use the device major and minor numbers of the device node through stat and continue with it in any case.
How to use
Testing done
Tested by copying the new binary to an Alpha release and tested with the new
/usrsetup from the minimal initrd.