flatcar-postinst: Use lazy unmount for /etc in temporary namespace #52
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There is a post-install action to prevent opaque directories (meaning any existing underlay directory is ignored) for those directories under /etc that the user might have created but we ship them later also in our /etc underlay. This action was not working when files were kept open under /etc because the unmount in the temporary namespace was not lazy. Use the lazy unmount option to address this. Signed-off-by: Kai Lueke <kailuke@microsoft.com>
chewi
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Oct 13, 2025
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Lazy unmount usually makes me feel uneasy, but it makes sense in this tiny context. The alternative would be to bind mount /etc somewhere else.
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When /etc way kept busy through, e.g., a process using it as CWD, then even in the temporary namespace unmounting failed unless it was done with the lazy option. This pulls in flatcar/update_engine#52 to address this. Signed-off-by: Kai Lueke <kailuke@microsoft.com>
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pothos
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When /etc way kept busy through, e.g., a process using it as CWD, then even in the temporary namespace unmounting failed unless it was done with the lazy option. This pulls in flatcar/update_engine#52 to address this. Signed-off-by: Kai Lueke <kailuke@microsoft.com>
pothos
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that referenced
this pull request
Oct 14, 2025
When /etc way kept busy through, e.g., a process using it as CWD, then even in the temporary namespace unmounting failed unless it was done with the lazy option. This pulls in flatcar/update_engine#52 to address this. Signed-off-by: Kai Lueke <kailuke@microsoft.com>
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There is a post-install action to prevent opaque directories (meaning any existing underlay directory is ignored) for those directories under /etc that the user might have created but we ship them later also in our /etc underlay. This action was not working when files were kept open under /etc because the unmount in the temporary namespace was not lazy. Use the lazy unmount option to address this.
How to use
That's something I would like to backport.
Testing done
Works, it runs again:
Could not remove "overlay.opaque" for /etc/extensionsis printedchangelog/directory (user-facing change, bug fix, security fix, update)/bootand/usrsize, packages, list files for any missing binaries, kernel modules, config files, kernel modules, etc.