BOOTC-INSTALL-CONFIG(5)

💖 BOOTC-INSTALL-CONFIG(5) 💖

okay bestie, so this is the manual page for bootc-install-config.toml — it lives in section 5 of the File Formats Manual, and it's literally the cheat sheet for how you customize your bootc install. grab a strawberry 🍓 and let's get into it.

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✨ NAME ✨

bootc-install-config.toml — no cap, that's the whole vibe of the name.

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🌸 DESCRIPTION 🌸

So like. The bootc install process supports customization through TOML drop-in files, and they hang out in these directories:

• /usr/lib/bootc/install
• /usr/local/lib/bootc/install
• /etc/bootc/install
• /run/bootc/install

If the same filename shows up in multiple of these directories, the file in the later directory in that list wins — it takes precedence, periodt. Then the selected files get processed in alphanumerical filename order.

Fragments whose match_architectures includes the current architecture — or which just don't have that field at all — are merged. And values like the root filesystem type get overridden when a later fragment specifies them. But kargs and karg-deletes lists? Those get appended, not replaced. 💅

The individual files all merge into one single final installation config. That's the whole point: it's supported for, like, a container base image to provide a default root filesystem type, and then that can be overridden in a derived container image. iconic behavior honestly.

install

This is the only defined toplevel table. 👑

The install section supports these subfields:

• block — An array of supported to-disk backends enabled by this base container image. If you don't specify it, this will just be direct. The only other supported value is tpm2-luks. The first value specified will be the default. To enable both, use block = ["direct", "tpm2-luks"].
• filesystem — See below. 👀
• kargs — An array of strings; this will be appended to the set of kernel arguments.
• match_architectures — An array of strings; this filters the install config.
• ostree — See below. 👀
• stateroot — The stateroot name to use. Defaults to default.
• root-mount-spec — A string specifying the root filesystem mount specification. For example, UUID=2e9f4241-229b-4202-8429-62d2302382e1 or LABEL=rootfs. If not provided, the UUID of the target filesystem will be used. An empty string signals to omit boot mount kargs entirely.
• boot-mount-spec — A string specifying the /boot filesystem mount specification. If not provided and /boot is a separate mount, its UUID will be used. An empty string signals to omit boot mount kargs entirely.
• discoverable-partitions — Boolean. When true, root discovery uses the Discoverable Partitions Specification via systemd-gpt-auto-generator and the root= kernel argument is omitted. This requires the bootloader to implement the Boot Loader Interface (BLI); systemd-boot always does, GRUB needs the bli module (available in newer builds). Defaults to true when using systemd-boot, false otherwise.
• enforce-container-sigpolicy — A boolean that controls whether to enforce that containers-policy.json (see man containers-policy.json for the full search path) includes a default policy which requires signatures. When true, image pulls will be rejected if the policy file specifies insecureAcceptAnything as the default. Defaults to false. This is equivalent to the --enforce-container-sigpolicy CLI flag.

filesystem

There is one valid field:

• root — An instance of "filesystem-root"; see below.

filesystem-root

There is one valid field:

• type — This can be any basic Linux filesystem with a mkfs.$fstype. For example, ext4, xfs, etc.

ostree

Configuration options for the ostree repository. There is one valid field:

• bls-append-except-default — A string of kernel arguments that will be appended to Boot Loader Spec entries, except for the default entry. This is useful for configuring arguments that should only apply to non-default deployments.

bootupd

Configuration options for bootupd, responsible of setting up the bootloader. There is only one valid field:

• skip-boot-uuid — A boolean that controls whether to skip writing partition UUIDs to the bootloader configuration. When true, bootupd is invoked with --with-static-configs instead of --write-uuid. Defaults to false (UUIDs are written by default).

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🦋 Examples 🦋

[install.filesystem.root]
type = "xfs"

[install]
kargs = ["nosmt", "console=tty0"]
stateroot = "myos"
root-mount-spec = "LABEL=rootfs"
boot-mount-spec = "UUID=abcd-1234"
enforce-container-sigpolicy = true

[install.ostree]
bls-append-except-default = 'grub_users=""'

Enable DPS auto-discovery for root (requires a BLI-capable bootloader):

[install]
discoverable-partitions = true

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👀 SEE ALSO 👀

• bootc(1)

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🌈 VERSION 🌈

v1.17.1

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and that's the whole page bestie 🫶 this was File Formats Manual energy, version v1.17.1, brought to you by the BOOTC-INSTALL-CONFIG(5) girlies. go forth and merge your fragments in alphanumerical order, you absolute icon. 💅✨🎀