[PATCH 0/2] initramfs-tools: add support to boot from Ceph RBD images

[Paul Emmerich <p.emmerich@first-colo.net>]

Hi,

the following patches add a new command line option "rbdboot" that contains
all necessary information to connect to a Ceph cluster, mount a RBD image
and boot from it.

The RBD image is mounted via the kernel RBD client (rbd.ko) which does not
require any special user-space binary. The typical initramfs in Debian with
the "most modules" configuration already contains all necessary kernel
modules: rbd, aes, and cbc
scripts/rbd uses /sys/bus/rbd/add [1] instead of the user-space binary "rbd"
to communicate with the kernel.


One difference from the NFS boot feature is that NFS allows configuration
via initramfs.conf which we did not implement. The reason for this is that
we cannot think of any scenario were it would make sense to configure the
Ceph connection statically in the initramfs. You need a network connection
anyways, so you can pass this information via the command line or dhcp...

Paul Emmerich
First Colo GmbH

[1] https://www.kernel.org/doc/Documentation/ABI/testing/sysfs-bus-rbd

Paul Emmerich (2):
  add support to boot directly from Ceph RBD images
  man pages: document rbdroot option

 hook-functions    |   4 +-
 init              |   3 +
 initramfs-tools.8 |   9 +++
 scripts/rbd       | 178 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 193 insertions(+), 1 deletion(-)
 create mode 100644 scripts/rbd

-- 
2.2.1