Enable image builds that use systemd mount units and kargs instead of writing /etc/fstab #1270
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Move the static TestPartitionTables into a function. Having them in a mutable, package-global, public map makes any modification in one test affect subsequent ones.
Add a Swap section and support for .swap systemd units. This commit also adds a separate filename regex for unit files that differs from the one we have for general files. Specifically, it allows for backslashes, which we will need to create .swap unit files. The filenames for these units must be the escaped path to the device or file they control, which can contain escape characters (e.g. \x2d for escaping a dash). The Service and Install sections are now marked 'omitempty' since they can be omitted (depending on the type of the unit). See also systemd.swap(5)
GenSystemdMountStages() generates systemd .mount and .swap stages based on a partition table. This is an alternative to generating an fstab stage for the mountpoints. The generator creates one systemd.unit.create stage for each mountpoint (and swap) and an extra stage that enables all the new units after they are written.
Test GenSystemdMountStages() using test partition tables from testdisk.
Add a boolean to each pipeline that generates a filesystem description (i.e. creates an org.osbuild.fstab stage), which when enabled will create systemd mount units instead of writing the static filesystem description to /etc/fstab.
Test all pipelines that support filesystem configuration switching between /etc/fstab and systemd .mount units. These are: - OS - OSTreeDeployment - RawBootcImage This commit also includes some test restructuring. - The OS pipeline tests have been moved to manifest_test, external to the manifest package. - Functions that are needed for both internal and external tests are defined and exported from the export_test.go file in the manifest package. We should move all tests to the external manifest_test package eventually. The testing is a little inconsistent now between different kinds of pipelines. Some run serializeStart() and serialize() in the same exported function, and others (bootc) export both. These should be made consistent, but for now it's okay.
Add a flag for enabling mount units on ImageConfig and copy the value to the OSCustomizations (for rpm-based disk images) and the OSTreeDploymentCustomizations.
Add repos for branched (42) and rawhide (43) to start testing. Generate the new gitlab config.
Make KernelOptions a string slice where each element is a separate option. This makes it easier to manipulate each option individually, which we will need later to modify default options when using mount units.
When /usr is on a separate mountpoint and we're not writing an /etc/fstab, the filesystem information should be included in the kernel cmdline arguments for autodiscovery to work.
The systemd-remount-fs service reads mount options from /etc/fstab for the root partition (and /usr, if separate). If there is no /etc/fstab, the fs is not remounted, so a read-only mount will stay read-only on boot. Switch the "ro" command line argument to "rw" if we're not writing an /etc/fstab file. Also, add the root mount options as rootflags.
Starting from Fedora 43, use mount units instead of writing /etc/fstab for the minimal-raw image type. Convert the image type declaration to a function of the distribution version so we can apply the configuration accordingly.
cgwalters
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Feb 27, 2025
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| if kernelOptions[idx] == "ro" { | ||
| kernelOptions[idx] = "rw" | ||
| break | ||
| } |
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It seems like it'd be cleaner to ensure that rw is injected from the start if mount units are in use.
| if err != nil { | ||
| panic(fmt.Sprintf("error getting filesystem options for / mountpoint: %s", err)) | ||
| } | ||
| kernelOptions = append(kernelOptions, fmt.Sprintf("rootflags=%s", fsOptions.MntOps)) |
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Cosmetic: Since most use cases don't use rootflags it'd be nice to not end up with rootflags=default, so we could special case that and not emit rootflags at all.
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I'll do a comment before I take a look at the code and say this is super nice and exciting to have. With a Fedora Minimal hat on: while we do plan to eventually have no- Can this PR include |
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This PR enables the use of systemd .mount (and .swap) units to replace writing an
/etc/fstabfile for the filesystem configuration. This is enabled for the Fedoraminimal-rawimage and its derivatives for Fedora 43 (rawhide) and above.The feature will be useful for bootc-image-builder, where filesystem configurations can be written at different stages (base container image build or disk build) and creating a systemd unit for each mount is more straightforward than merging different entries in an
/etc/fstabfile.The lack of an
/etc/fstabrequires a few changes to kernel commandline arguments and the partition table. Each change is described in its respective commit message, but I also summarise here:/usrpartition, if separate from/, must be defined in the kernel command line arguments.rwduring initial boot, because the lack of/etc/fstabmeans that the systemd-remount-fs service will not discover the mount options for/(and/usr) to remount them./mount options (rootflags) need to be defined in the kernel command line arguments.This PR requires osbuild/osbuild#2001.