Documentation
¶
Overview ¶
Package initbuild produces the initramfs cpio.gz consumed by the LinuxBootLoader path.
The artefact is a "newc"-format cpio archive (the format the Linux kernel's initrd loader expects), gzipped. The kernel unpacks it into the initial rootfs (tmpfs) and runs /init as PID 1. For mono-container that init is `weft-microvm-init`; for pod mode it's `weft-init`, and the same archive also carries the helper binaries the guest execs (crun, cfs-client, the in-VM agent) at their own paths — no go:embed, no extraction copy, the kernel places them directly.
Cross-compilation is deliberately NOT done here: the operator produces the Linux binaries (`GOOS=linux GOARCH=<arch> go build …`) and passes their paths. Keeps this package small and reusable.
Index ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func Pack ¶
Pack writes a single-entry initramfs (/init = initBinary). Thin back-compat wrapper over PackFiles for the mono-binary case.
func PackFiles ¶
PackFiles writes a gzipped newc cpio archive to out containing each File at its Path (with parent directory entries emitted first), all owned by root:root. This is how a pod-mode initramfs carries /init plus the helper binaries (bin/crun, bin/cfs-client, bin/weft-microvm-agent) the guest execs from $PATH.
Both the cpio trailer and the gzip footer are flushed explicitly; a close failure surfaces as the function's error rather than silently producing a truncated archive a kernel cannot unpack.
func PackFilesToFile ¶
PackFilesToFile is the convenience wrapper that opens dst (0644) and hands it to PackFiles. Close errors surface as the return value, so a short write at flush time (disk full, quota) doesn't leave a truncated initramfs on disk under the guise of success.
func PackToFile ¶
PackToFile is the convenience wrapper that opens dst (0644) and hands it to Pack. Close errors surface as the return value so a short write at flush time doesn't leave a truncated initramfs.
func PodInitrd ¶
PodInitrd packs a pod-mode initramfs at dst: /init (weft-init) plus the guest helper binaries at bin/<name> (crun, cfs-client, the in-VM agent). Empty helper paths are skipped, so a build can ship only what it needs. The guest resolves them from $PATH (/bin) — no go:embed, no extraction.
Types ¶
type File ¶
type File struct {
// Path is the in-initramfs path with no leading slash, e.g. "init"
// or "bin/crun". Parent directories are created automatically.
Path string
// Source is the host path to read the bytes from.
Source string
// Mode is the unix permission bits; 0 defaults to 0755.
Mode uint32
}
File is one regular-file entry to place in the initramfs.
Source Files