Because this script enables `set -u` when no arguments are provided bash
exits with the error:
$1: unbound variable
instead of the helpful usage message.
NixOS 20.03 is built on kernel 5.4 and 19.09 is on 4.19, so we should update
this option to the highest value possible, per linked upstream instructions from
Amazon.
For the case of blkfront drives, there appears to be no difference
between /dev/sda1 and /dev/xvda: the drive always appears as the
kernel device /dev/xvda.
For the case of nvme drives, the root device typically appears as
/dev/nvme0n1. Amazon provides the 'ec2-utils' package for their first
party linux ("Amazon Linux"), which configures udev to create symlinks
from the provided name to the nvme device name. This name is
communicated through nvme "Identify Controller" response, which can be
inspected with:
nvme id-ctrl --raw-binary /dev/nvme0n1 | cut -c3073-3104 | hexdump -C
On Amazon Linux, where the device is attached as "/dev/xvda", this
creates:
- /dev/xvda -> nvme0n1
- /dev/xvda1 -> nvme0n1p1
On NixOS where the device is attach as "/dev/sda1", this creates:
- /dev/sda1 -> nvme0n1
- /dev/sda11 -> nvme0n1p1
This is odd, but not inherently a problem.
NixOS unconditionally configures grub to install to `/dev/xvda`, which
fails on an instance using nvme storage. With the root device name set
to xvda, both blkfront and nvme drives are accessible as /dev/xvda,
either directly or by symlink.
Since 34234dcb51, for resize2fs to be automatically included in
initrd, a filesystem needed for boot must be explicitly defined as an
ext* type filesystem.
Cloudstack images are simply using cloud-init. They are not headless
as a user usually have access to a console. Otherwise, the difference
with Openstack are mostly handled by cloud-init.
This is still some minor issues. Notably, there is no non-root user.
Other cloud images usually come with a user named after the
distribution and with sudo. Would it make sense for NixOS?
Cloudstack gives the user the ability to change the password.
Cloud-init support for this is imperfect and the set-passwords module
should be declared as `- [set-passwords, always]` for this to work. I
don't know if there is an easy way to "patch" default cloud-init
configuration. However, without a non-root user, this is of no use.
Similarly, hostname is usually set through cloud-init using
`set_hostname` and `update_hostname` modules. While the patch to
declare nixos to cloud-init contains some code to set hostname, the
previously mentioned modules are not enabled.
As suggested in https://github.com/NixOS/nixpkgs/pull/39416#discussion_r183845745
the versioning attributes in `lib` should be consistent to
`nixos/version` which implicates the following changes:
* `lib.trivial.version` -> `lib.trivial.release`
* `lib.trivial.suffix` -> `lib.trivial.versionSuffix`
* `lib.nixpkgsVersion` -> `lib.version`
As `lib.nixpkgsVersion` is referenced several times in `NixOS/nixpkgs`,
`NixOS/nix` and probably several user's setups. As the rename will cause
a notable impact it's better to keep `lib.nixpkgsVersion` as alias with
a warning yielded by `builtins.trace`.
- Add a new parameter `imageType` that can specify either "efi" or
"legacy" (the default which should see no change in behaviour by
this patch).
- EFI images get a GPT partition table (instead of msdos) with a
mandatory ESP partition (so we add an assert that `partitioned`
is true).
- Use the partx tool from util-linux to determine exact start + size
of the root partition. This is required because GPT stores a secondary
partition table at the end of the disk, so we can't just have
mkfs.ext4 create the filesystem until the end of the disk.
- (Unrelated to any EFI changes) Since we're depending on the
`-E offset=X` option to mkfs which is only supported by e2fsprogs,
disallow any attempts of creating partitioned disk images where
the root filesystem is not ext4.
