Rewrite coreos-install

[marineam]

Longer term we will want a more complete OS installer that can do tasks like setup RAID/LVM, user accounts, etc. that people typically expect from a Linux distro. Sorter term all we've got is what coreos-cloudinit can do but just writing a image to disk and injecting the config is overly painful because the coreos-install script is so flaky. Issues include:

• Failures not clearly reported, if at all.
• Race condition between script and udev can prevent the partition scan from working correctly.
• No sane way to evolve coreos-install into the installer we want some day.

So we need a new tool, written in a real language, with some special care to report errors clearly and recover from transient issues.

[mark-kubacki]

Are there any constraints to programming language and file size? For example, would a 8 MB installer in Golang do?

[crawford]

I don't think this is a priority anymore. coreos-install has been largely stabilized and with the introduction of Ignition, we have the ability to do all of the things mentioned above.

[bgilbert]

I think this is still worth considering. Things it would let us do:

• Validate Ignition configs
• Validate cloud-configs on platforms other than Container Linux
• Support CLCs, if we want
• Refuse to install to disks with mounted partitions (by using ioctls to check for exclusive access)
• Support 4 KB sector disks (Allow installing Container Linux on a disk with 4 KB sectors #2109)