source_remote imageboot.sh is the last thing the diskless cmdline hook
runs, so returning early on a failed extraction ended the hook and left
dracut to time out. Falling through instead reaches the existing
/sysroot/sbin/init guard, which reports the failure and holds the node so
it stays reachable over ssh, as it did before extraction was checked.
`unsquashfs` can use multiple CPU cores during image extraction, significantly reducing boot time.
For example the whole boot time from PXE to shell on a 8-core VM, from approximately 45 seconds to 20 seconds.
This PR adds `squashfs-tools` as a dependency. Since the package is smaller than 1 MB, the additional image size is justified by the performance improvement.
For backward compatibility, the existing `cp`-based extraction method is used when `unsquashfs` is unavailable, such as with images built before this change.
The extraction logic has also been moved into the common functions and is now shared between EL9, EL10, and Ubuntu.
Both untethered `squashfs` images and `confluent_multisquash` images are supported.
Images must be rebuilt to include `unsquashfs` and benefit from the faster extraction path.
Centralize the SELinux chcon helper and use it for downloaded
systemd units, onboot hooks, and apiclient files across EL7 through EL10.
Include chcon in captured EL initramfs images.
Without this fix the onboot services failed to start on SELinux enabled
captured image.
This allows the FS to just live, uncompressed, in cache.
This is generally a bad idea, however:
- In a hypothetically super-tuned diskless image, the lack of double-cache can offset the lack of compression
- The image will have supreme read performance
- It will have the most deterministic memory behavior
By default, the squashfs file was being cached as well as the contents after extraction.
This is superfluous pressure on the cache of the OS.
However, it does help keep the image afloat through 'confignet', so
leave it on until onboot completes, then reclaim cache and disable further caching.
Rather than treat both as the same, since untethered has everything up front anyway, go ahead and extract the filesystem.
This makes the mount look more straightforward and makes it so deletion of files from
the image also frees ram.
If debugssh is not requsted, the initramfs is not needed.
Do not unshare the mount namespace, leave the kernel relevant namespace 'normal'
Remove some initramfs content to free up some memory.
Jarrod Johnson
Markus Hilger
Jarrod Johnson