2008-09-28
Why I hate Solaris 10's service facility right now
I have a production Solaris 10 x86 server with an onboard serial port. I
want to make the Solaris 10 equivalent of a getty process listen on
it, so that I can still log in when the system's network falls off a
cliff. Ideally it would do so with a (fixed) baud rate of my choice.
This is all that I want to do; in particular, I do not want to make
the serial port into the system console (especially as this would
require a reboot and, as mentioned, this is a production server).
And I need to do this without running a GUI, because my connection
to this server is very limited right now.
(Those of you with Solaris 10 experience may be laughing helplessly right now.)
You might think that this would be reasonably simple. You would be
sorely disappointed. Solaris 10 handles all of this with a new system,
the 'Service Access Controller' (sac, ttymon, and several other
bits), which is absurdly complex and cryptic, not to mention rather
under-documented (with beautiful touches like the ttyadm program not
being how you administer tty ports).
The problem with all this being absurdly complex and cryptic is not
just that it is all but impossible to do things if you are not deeply
steeped in their arcana, but also that trying to solve the problem by
reading manpages and just trying things is not an option. Usually on an
unfamiliar Unix, I can fumble my way around to solve problems because
I understand enough of the basic logic of the system to let me avoid
making terrible, damaging mistakes (at the most I will make localized
messes that I can clean up). Not so with Solaris 10's ttymon system;
absurdly complex things that I do not completely understand and am doing
for the first time are not things that I can touch on a production
machine. Especially in a crisis, which is exactly why I want to set
this up in the first place.
(What makes this all the more frustrating is that I think I may know how to solve the problem, but I dare not try it out on a production system.)