[Planetlab-users] Slices on a node

[Steve Muir]

On Mon, 9 May 2005, Lluis wrote:

> Hi all,
>
> I want to put a little program on a node that should tell me whenever a new
> slice is started or stopped on that node.

right now there isn't really a notion of a slice being 'started or 
stopped' on a node, just 'created or not'.

> Putting that program on several nodes, I want to be aware of what's on each
> node and do some "callbacks" whenever something changes (inform some other
> nodes), without having to ask PlanetLab Central every time (I should ask PLC
> only for those new nodes that my program is not on).
>
> Do you know if there's any way to do that? Somewhere to look at?

there are ways of asking the Node Manager for the list of slices currently 
created on the node, but they have mostly been used for internal 
monitoring and thus aren't documented anywhere (this will be fixed in the 
near future as the NM interface solidifies).  for example, you can read
from the URL

http://localhost:813/live_slices

to get a CSV-format list of slices and the agent that created each slice 
(pl_conf in almost every case).



> I would also like to have access to the ssh key of a slice (to do some sort
> of encrypted multicast communication), but I think it's not available from
> inside de PlanetLab nodes.

the keys are available on the nodes, but only the keys associated with 
your slice are accessible by default.  i'm not sure that ssh public keys 
can be easily used outside the ssh applications though, they're not quite 
in the same format as, say, openssl uses (PEM).