> > $dracut --regenerate-all --force
>
> This is not "leverage the scripts in CentOS to pull in
> appropriate drivers";

None of the dracut versions I've found on Centos8 include the
--regenerate-all flag ... what version of dracut is this?

[root@c8-vm ~]# dracut --regenrate-all /tmp/initrd2.img `uname -r`
getopt: unrecognized option '--regenrate-all'
Usage: /usr/bin/dracut [OPTION]... [<initramfs> [<kernel-version>]]

Version: 049-70.git20200228.el8

Creates initial ramdisk images for preloading modules

  -h, --help  Display all options

If a [LIST] has multiple arguments, then you have to put these in quotes.

For example:

    # dracut --add-drivers "module1 module2"  ...



> this is pull everything in.

I'm not sure about this, I could be wrong.  There *is* an option which does
pull in most/all modules:

  -H, --hostonly        Host-Only mode: Install only what is needed for
                        booting the local host instead of a generic host.
  -N, --no-hostonly     Disables Host-Only mode
  --hostonly-mode <mode>
                        Specify the hostonly mode to use. <mode> could be
                        one of "sloppy" or "strict". "sloppy" mode is used
                        by default.
                        In "sloppy" hostonly mode, extra drivers and modules
                        will be installed, so minor hardware change won't make
                        the image unbootable (eg. changed keyboard), and the
                        image is still portable among similar hosts.
                        With "strict" mode enabled, anything not necessary
                        for booting the local host in its current state will
                        not be included, and modules may do some extra job
                        to save more space. Minor change of hardware or
                        environment could make the image unbootable.
                        DO NOT use "strict" mode unless you know what you
                        are doing.

Depending on the discussion I've raised on whether the MAAS
produced Centos8 initramfs should closer match what the Ubuntu
initrd has (it's built for booting on hardware) the use
--no-hostonly should produce a larger, more complete initramfs
which would likely include storage modules like NVME.)

On a centos8 vm with virtio disks (no nvme), I created initramfs
3 ways:

  --hostonly --hostonly-mode=strict
  --hostonly --hostonly-mode=sloppy
  --no-hostonly

[root@c8-vm ~]# ls -ahl /tmp/initrd*
-rw------- 1 root root 17M Feb 17 19:24 /tmp/initrd-host-sloppy.img
-rw------- 1 root root 17M Feb 17 19:23 /tmp/initrd-host-strict.img
-rw------- 1 root root 28M Feb 17 19:22 /tmp/initrd-nohost.img

On this setup, there's no practical difference between
strict/sloppy; and neither pull in the NVME module as it's not in
use.  But the nohots only does


root@c8-vm ~]# lsinitrd /tmp/initrd-nohost.img | grep nvme | awk '{print $9}'
usr/lib/modules/4.18.0-193.19.1.el8_2.centos.plus.x86_64/kernel/drivers/nvme
usr/lib/modules/4.18.0-193.19.1.el8_2.centos.plus.x86_64/kernel/drivers/nvme/host
usr/lib/modules/4.18.0-193.19.1.el8_2.centos.plus.x86_64/kernel/drivers/nvme/host/nvme-core.ko.xz
usr/lib/modules/4.18.0-193.19.1.el8_2.centos.plus.x86_64/kernel/drivers/nvme/host/nvme-fabrics.ko.xz
usr/lib/modules/4.18.0-193.19.1.el8_2.centos.plus.x86_64/kernel/drivers/nvme/host/nvme-fc.ko.xz
usr/lib/modules/4.18.0-193.19.1.el8_2.centos.plus.x86_64/kernel/drivers/nvme/host/nvme-rdma.ko.xz
usr/lib/modules/4.18.0-193.19.1.el8_2.centos.plus.x86_64/kernel/drivers/nvme/host/nvme-tcp.ko.xz
usr/lib/modules/4.18.0-193.19.1.el8_2.centos.plus.x86_64/kernel/drivers/nvme/host/nvme.ko.xz
usr/lib/modules/4.18.0-193.19.1.el8_2.centos.plus.x86_64/kernel/drivers/nvme/target
usr/lib/modules/4.18.0-193.19.1.el8_2.centos.plus.x86_64/kernel/drivers/nvme/target/nvme-loop.ko.xz
usr/lib/modules/4.18.0-193.19.1.el8_2.centos.plus.x86_64/kernel/drivers/nvme/target/nvmet-fc.ko.xz
usr/lib/modules/4.18.0-193.19.1.el8_2.centos.plus.x86_64/kernel/drivers/nvme/target/nvmet.ko.xz


The last test that'd be interesting is running dracut --hostonly
mode while booted into Ubuntu but chrooted into centos8
filesystem (which recreates what
curtin does/could do).