using cfrun to only take action on hosts in defined group

[Steve Wray]

Hi there,

We run xen servers and lots of xen virtual machines are now under 
cfengine control, lovely :)

I'd like to be able to send a 'halt' to every xen instance on a 
particular xen host.

It seems as if I should be able to do something like:
------------
control:
   any::
      actionsequence = ( shellcommands )

groups:
   any::
      # where these two hosts are instances on a xen server:
      xeninstances = ( xeninstance1 xeninstance2 )

shellcommands:
   xen3instances.Shutdown.Now::
      "/bin/echo would halt this host"

alerts:
   xen3instances::
      "xen3 instance hit"

   xen3instances.Shutdown.Now::
      "xen3 instance shutting down"

-----------

and that I should be able to shut down only the hosts listed in 
xen3instances by running:

cfrun -- -Dxen3instances.Shutdown.Now

what actually happens is that I get the alert:

"xen3 instance shutting down"

for every single host listed in cfrun.hosts

this would be bad...

If I use:
cfrun -- -DShutdown.Now

it works as expected, but seems unnatural... I'm looking for a way to 
run any actions which are already defined, from cfrun against a group of 
hosts specified on the cfrun commandline.

Eg, I already have a cfengine script to update debian packages, I want 
to define a class of 'staging servers' and be able to run this existing 
cfengine action against that group and no others.

Since I've already defined an action and I can add a group easily 
enough, this would seem natural.

any ideas? I am guessing that I am missing something in the way that 
cfrun operates? Should the group definitions go into cfservd.conf on the 
cfserver or clients? cfagent.conf on the server or clients? Lots of 
possibilities :)

Thanks!


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