Since the `--once` option of `extlinux` seems to only work with BIOS, we
needed to change to remove any reliance on this option. Instead of
booting the upgraded version once, and then making it the default after
a successful boot, we now make it the default, and then revert on any
boot error.
Signed-off-by: Andrew Rynhard <andrew@andrewrynhard.com>
This PR introduces a new strategy for upgrades. Instead of attempting to
zap the partition table, create a new one, and then format the
partitions, this change will only update the `vmlinuz`, and
`initramfs.xz` being used to boot. It introduces an A/B style upgrade
process, which will allow for easy rollbacks. One deviation from our
original intention with upgrades is that this change does not completely
reset a node. It falls just short of that and does not reset the
partition table. This forces us to keep the current partition scheme in
mind as we make changes in the future, because an upgrade assumes a
specific partition scheme. We can improve upgrades further in the
future, but this will at least make them more dependable. Finally, one
more feature in this PR is the ability to keep state. This enables
single node clusters to upgrade since we keep the etcd data around.
Signed-off-by: Andrew Rynhard <andrew@andrewrynhard.com>
Firecracker launches tries to open VM disk image before every boot,
parses partition table, finds boot partition, tries to read it as FAT32
filesystem, extracts uncompressed kernel from `bzImage` (firecracker
doesn't support `bzImage` yet), extracts initramfs and passes it to
firecracker binary.
This flow allows for extended tests, e.g. testing installer, upgrade and
downgrade tests, etc.
Bootloader emulation is disabled by default for now, can be enabled via
`--with-bootloader-emulation` flag to `osctl cluster create`.
Signed-off-by: Andrey Smirnov <smirnov.andrey@gmail.com>
