Checking the root filesystem before mounting it is always a good idea.
But after changing the root filesystem, it is especially important to
(re-)check it to ensure everything went fine. So add that check.
The 'ROOTFLAGS' parameter should NOT be quoted as it then introduces an
(empty) extra argument to 'mount', causing a boot failure.
Thanks to 'mjt' for the help and identifying the issue.
Lessons learned:
1) Don't blindly follow the *suggestions* that shellcheck makes
2) Test your changes (properly) before submitting/merging them
ad 1) I find shellcheck a very useful tool, but it doesn't (and likely
can't) understand the full context. The developer does (or should) and
should evaluate each suggestion whether it's applicable in this case.
ad 2) This should've been obvious and certainly for me.
I'm normally very dilligent and test all my changes, but I got sloppy
this time and did not. With logical consequences.
SC2154: var is referenced but not assigned.
The 'rootmnt' variable is set in /usr/share/initramfs-tools/init and if
it's not available, that would be bad.
According to SC2154 you can fix that issue by using '${var:?}' so it
would fail if unset or empty.
So apply that and reference that SC item in the comments.
Also remove it from the exclude list in the CI config file.
sfdisk is a bit crusty - it doesn't understand gpt partition tables very well,
for example. By switching to parted, we can handle gpt issues (which may be
useful in the future, and is definitely useful for other boards), and we no
longer have to hardcode that 4M alignment workaround. Parted will tell us
the free space at the end of the disk.
Because we're already using partprobe, there's no additional dependencies
needed.
Switch away from using a systemd service for the initial root resize.
Instead, we resize the root partition and filesystem in the initrd.
To simplify things, the initrd script will check whether it should resize
the partition on every boot. It does this by checking if the entire disk
(ignoring an empty 4MB) is in use. However, the scripts themselves are
deleted from the system after the initrd is generated. After the image
is installed, the resize script should exist only in the initrd. When the
kernel gets upgraded (eg, for a security update) or a new initrd is generated
due to a package install, the new initrd will not contain the resize script.
At that point, nothing will remain from the image's initial resize
bootstrapping process.
This process (but not the scripts) is similar to what cloud-initramfs-growroot
does. However, that particular package has an indirect dependency on Python,
and we don't necessarily want that overhead in our images just for resizing.
Diederik de Haas