[RFC] Making D-Bus suitable for being run early during boot

[Lennart Poettering]

On Fri, 09.07.10 11:17, Havoc Pennington (hp at pobox.com) wrote:

> 
> I guess we need some FHS lawyers to come tell us what to do when there
> are conflicting rules :-P
> 
> To me it seems like /var/lib should just be available in early boot.
> Why isn't it, is this so early it's mounted read-only?

Well, in theory / can be read-only the entire time the machine is
up. Some distributions support this out-of-the-box. Fedora currently
doesn't, but I actually believe it would be worthy goal to make Fedora
use a read-only / by default too, which would only be remounted writable
during package installation and when the user changes
configuration.

OTOH /var is writable and has to be writable from the time on it is
first mounted.

> iirc machine-id would normally be created on demand the first time you
> boot with a new install, so it will fail if there's no way to write

Well, that would even be fixable: generate an id, but don't fial if it
cannot be writtten to disk, and then write it to disk later on, when the
fs is writable.

Something similar is done with various other records that are written on
boot. For example, the utmp boot record is usually delayed the same way.

Lennart

-- 
Lennart Poettering - Red Hat, Inc.