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…ader These are the on-disk VM images for mantsana, a macOS CI VM backend replacing Tart (see the DESIGN.md that follows), and a way to get them for now. An image is a directory of plain files: a manifest (hardware model, machine identifier, CPUs, memory, display, MTU), a raw sparse disk, and the macOS auxiliary storage (NVRAM). A warm subdirectory holds a saved VM memory snapshot and the disk and NVRAM it goes with, for restoring in seconds instead of cold booting. Snapshots are only usable on the host OS build and at the VM size they were saved with, so WarmUsable checks, and a failed restore can mark one stale. cmd/oci-img-dl (package ocidl) downloads the macOS VM images corp CI uses today, published to OCI registries such as ghcr.io/cirruslabs/macos-tahoe-xcode, straight into such an image. Their disks are 512 MiB chunks in Apple's LZ4 stream framing, each annotated with its uncompressed SHA-256, which is verified. Chunks download in parallel, all-zero pages are left as holes, and interrupted downloads resume. It's for development and the transition; mantsana's own image distribution will be different. Updates tailscale/corp#39994 Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com> Change-Id: I54ff615054bbe0ff0e1fecfa920ffa2c947bd6e7
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These are the on-disk VM images for mantsana, a macOS CI VM backend
replacing Tart (see the DESIGN.md that follows), and a way to get them
for now.
An image is a directory of plain files: a manifest (hardware model,
machine identifier, CPUs, memory, display, MTU), a raw sparse disk, and
the macOS auxiliary storage (NVRAM). A warm subdirectory holds a saved
VM memory snapshot and the disk and NVRAM it goes with, for restoring in
seconds instead of cold booting. Snapshots are only usable on the host
OS build and at the VM size they were saved with, so WarmUsable checks,
and a failed restore can mark one stale.
cmd/oci-img-dl (package ocidl) downloads the macOS VM images corp CI uses
today, published to OCI registries such as
ghcr.io/cirruslabs/macos-tahoe-xcode, straight into such an image. Their
disks are 512 MiB chunks in Apple's LZ4 stream framing, each annotated
with its uncompressed SHA-256, which is verified. Chunks download in
parallel, all-zero pages are left as holes, and interrupted downloads
resume. It's for development and the transition; mantsana's own image
distribution will be different.
Updates tailscale/corp#39994