Each node that MAAS prepares for you has your ssh key on it, so you
can automate these tasks using any method that can use ssh as
transport, so that certainly includes Juju.
That pushes you into the realm of customising your charms to do these
set-up tasks, which might fit your expectations, but is going to be
awkward if you're using off-the-shelf charms. However, I'm not the
best person to talk about the Juju side of things, but I can address
the other tasks.
Below I'm talking about MAAS in Quantal (i.e. 12.10, out soon) which
is fairly different from MAAS in 12.04, though there is an upgrade
path. I suspect that none of the following applies to MAAS as shipped
in 12.04.
Configure ntp on the nodes.
By default they'll be set-up to run ntp, using ntp.ubuntu.com. If
that's not suitable, and you'd rather not add a post-allocation step
to do it (i.e. configure via ssh as above, once the machine is up
and running), you may want to change the preseed that MAAS uses.
Search for the file preseed_master; that and the generic file in
the same directory are templates used to generate the final preseed
sent to booting machines.
The Debian
Installer page links
to the manuals. Choose one of those
and see Appendix B, Automating the installation using preseeding
for an introduction to preseeding.
Bear in mind that any changes to preseed_master or its siblings
will be overwritten during upgrades, so keep a record of your
changes around. We will almost certainly be making this whole
process easier for 13.04.
Set the video mode on the nodes.
Nothing is set in the preseed right now, so you'll have to do this
in a post-allocation step, or by editing the preseed templates.
Set the timezone on the nodes.
It's set to UTC by default. Do you really want to change this? For
servers, at least, it's very normal to run with UTC. Your mention of
video mode setting makes me thing you're using this for desktops
though, in which case the answer is the same as for #2.