Node Manager API Documentation


Introduction

The PlanetLab Node Manager API (NMAPI) is the interface through which the slices access the Node API.


Authentication

Authentication for NM operations is based on the identity of the connecting slice. For slices whose roles are defined as 'nm-controller', the target slice must be listed delegated and as controlled by the calling slice.


Connection

The NM XMLRPC server listens locally on every PlanetLab node at http://localhost:812.

The NM XMLRPC server can be accessed remotely using an SSH connection through the nm-controller account. Rather than a standard shell, a special command is run that forwards all standard input to the local XMLRPC server, essentially XML-RPC over ssh.


An Example using the PLC and NM API

The nm-controller slice is given a stub account such that it can be accessed over ssh. So rather than logging into NM server listens locally on every PlanetLab node at http://localhost:812.


controller_slice_fields = {'name'      : 'princeton_mycontroller',
                           'instantiation' : 'nm-controller',
                           'url'           : 'http://www.yourhost.com', 
                           'description'   : 'a brief description of this slice.', }
controller_slice_id = api.AddSlices(plauth, controller_slice_fields)
      

After this, the controller owner, should both add users and nodes to this slice. As well, becasue this account is created using the standard NM mechanism, you should wait at least 15 minutes for the controller slice to be instantiated on all the nodes you'd like to access it.

Subsequently, slices that will be delegated to this controller will be registered at PLC. An example follows.


delegated_slice_fields = {'name'        : 'anothersite_mydelegated',
                        'instantiation' : 'delegated',
                        'url'           : 'http://www.yourhost.com', 
                        'description'   : 'a brief description of this slice.', }
delegated_slice_id = api.AddSlices(plauth, delegated_slice_fields)

# Get ticket for this slice.
ticket = api.GetSliceTicket(plauth, "princetondsl_solteszdelegated")
	

After the slice is registered with PLC, and your application has the Ticket, the last step is to redeem the ticket by presenting it to the NM through the nm-controller account. THe following code formats the message correctly.


# generate an XMLRPC request.
print xmlrpclib.dumps((ticket,), 'Ticket')
	

Finally, this message must be sent to the NM using the controller account. It should be possible to create a program that creates the ssh connection or to use a library that does this automatically such as: pyXMLRPCssh

Or, you could use something much simpler. Assuming the output from dumps() above, is saved to a file called ticket.txt, you could run a command like:


cat ticket.txt | ssh princeton_mycontroller@mynode.someuniversity.edu
	

Alternately,


p = subprocess.Popen(['/usr/bin/ssh', 'princeton_mycontroller@mynode.someuniversity.edu'], 
					stdin=subprocess.PIPE, stdout=subprocess.PIPE)
print >>p.stdin, xmlrpclib.dumps((ticket,), 'Ticket')
p.stdin.close()
print xmlrpclib.loads(p.stdout.read())
p.wait() 
	

The following is a stub to use as you would use the current xmlrpclib.Server() object, but redirects the connection of SSH.


"""XML-RPC over SSH.

	To use, create an XmlRpcOverSsh object like so:
		>>> api = XmlRpcOverSsh('princeton_deisenst@planetlab-1.cs.princeton.edu')
	and call methods as with the normal xmlrpclib.ServerProxy interface.
"""

from subprocess import PIPE, Popen
from xmlrpclib import Fault, dumps, loads

__all__ = ['XmlRpcOverSsh']


class XmlRpcOverSsh:
    def __init__(self, userAtHost):
        self.userAtHost = userAtHost

    def __getattr__(self, method):
        return _Method(self.userAtHost, method)


class _Method:
    def __init__(self, userAtHost, method):
        self.userAtHost = userAtHost
        self.method = method

    def __call__(self, *args):
        p = Popen(['ssh', self.userAtHost], stdin=PIPE, stdout=PIPE)
        stdout, stderr = p.communicate(dumps(args, self.method))
        if stderr:
            raise Fault(1, stderr)
        else:
            return loads(stdout)
	

PlanetLab API Methods


Create

Prototype:

Create (sliver_name)

Description:

Create a non-PLC-instantiated sliver

Allowed Roles:

nm-controller, self

Parameters:

  • sliver_name : string, A sliver/slice name.

Returns:

  • int, 1 if successful


Destroy

Prototype:

Destroy (sliver_name)

Description:

Destroy a non-PLC-instantiated sliver

Allowed Roles:

nm-controller, self

Parameters:

  • sliver_name : string, A sliver/slice name.

Returns:

  • int, 1 if successful


GetEffectiveRSpec

Prototype:

GetEffectiveRSpec (sliver_name)

Description:

Return the RSpec allocated to the specified sliver, including loans

Allowed Roles:

nm-controller, self

Parameters:

  • sliver_name : string, A sliver/slice name.

Returns:

  • struct, A resource specification


GetLoans

Prototype:

GetLoans (sliver_name)

Description:

Return the list of loans made by the specified sliver

Allowed Roles:

nm-controller, self

Parameters:

  • sliver_name : string, A sliver/slice name.

Returns:

  • array of string or string or int

    • string, recipient slice name

    • string, resource name

    • int, resource amount


GetRSpec

Prototype:

GetRSpec (sliver_name)

Description:

Return the RSpec allocated to the specified sliver, excluding loans

Allowed Roles:

nm-controller, self

Parameters:

  • sliver_name : string, A sliver/slice name.

Returns:

  • struct

    • resource name : int, amount


GetSSHKeys

Prototype:

GetSSHKeys ()

Description:

Return an dictionary mapping slice names to SSH keys

Allowed Roles:

self

Parameters:

  • None

Returns:

  • struct

    • sliver_name : string, the associated SSHKey


GetXIDs

Prototype:

GetXIDs ()

Description:

Return an dictionary mapping Slice names to XIDs

Allowed Roles:

self

Parameters:

  • None

Returns:

  • struct

    • sliver_name : int, the associated xid


Help

Prototype:

Help ()

Description:

Get a list of functions currently supported by the Node Manager API

Allowed Roles:

self

Parameters:

  • None

Returns:

  • array, A list of supported functions


SetLoans

Prototype:

SetLoans (sliver_name, loans)

Description:

Overwrite the list of loans made by the specified sliver.

Also, note that SetLoans will not throw an error if more capacity than the RSpec is handed out, but it will silently discard those loans that would put it over capacity. This behavior may be replaced with error semantics in the future. As well, there is currently no asynchronous notification of loss of resources.

Allowed Roles:

nm-controller, self

Parameters:

  • sliver_name : string, A sliver/slice name.

  • loans : array of string or string or int

    • string, recipient slice name

    • string, resource name

    • int, resource amount

Returns:

  • int, 1 if successful


Start

Prototype:

Start (sliver_name)

Description:

Run start scripts belonging to the specified sliver

Allowed Roles:

nm-controller, self

Parameters:

  • sliver_name : string, A sliver/slice name.

Returns:

  • int, 1 if successful


Stop

Prototype:

Stop (sliver_name)

Description:

Kill all processes belonging to the specified sliver

Allowed Roles:

nm-controller, self

Parameters:

  • sliver_name : string, A sliver/slice name.

Returns:

  • int, 1 if successful


Ticket

Prototype:

Ticket (ticket)

Description:

The Node Manager periodically polls the PLC API for a list of all slices that are allowed to exist on the given node. Before actions are performed on a delegated slice (such as creation), a controller slice must deliver a valid slice ticket to NM.

This ticket is the value retured by PLC's GetSliceTicket() API call,

Allowed Roles:

self

Parameters:

  • ticket : string, A ticket returned from GetSliceTicket()

Returns:

  • int, 1 if successful