emuvim/dcemulator/node.py

   1 """
   2 Distributed Cloud Emulator (dcemulator)
   3 (c) 2015 by Manuel Peuster <manuel.peuster@upb.de>
   4 """
   5 import logging
   6
   7
   8 DCDPID_BASE = 1000  # start of switch dpid's used for data center switches
   9
  10
  11 class Datacenter(object):
  12     """
  13     Represents a logical data center to which compute resources
  14     (Docker containers) can be added at runtime.
  15
  16     Will also implement resource bookkeeping in later versions.
  17     """
  18
  19     def __init__(self, name):
  20         self.net = None  # DCNetwork to which we belong
  21         self.name = name
  22         self.switch = None  # first prototype assumes one "bigswitch" per DC
  23         self.containers = {}  # keep track of running containers
  24
  25     def _get_next_dc_dpid(self):
  26         global DCDPID_BASE
  27         DCDPID_BASE += 1
  28         return DCDPID_BASE
  29
  30     def create(self):
  31         """
  32         Each data center is represented by a single switch to which
  33         compute resources can be connected at run time.
  34
  35         TODO: This will be changed in the future to support multiple networks
  36         per data center
  37         """
  38         self.switch = self.net.mnet.addSwitch(
  39             "%s.s1" % self.name, dpid=hex(self._get_next_dc_dpid())[2:])
  40         logging.debug("created data center switch: %s" % str(self.switch))
  41
  42     def start(self):
  43         pass
  44
  45     def addCompute(self, name, image=None, network=None):
  46         """
  47         Create a new container as compute resource and connect it to this
  48         data center.
  49
  50         TODO: This interface will change to support multiple networks to which
  51         a single container can be connected.
  52         """
  53         assert name is not None
  54         # set default parameter
  55         if image is None:
  56             image = "ubuntu"
  57         if network is None:
  58             network = {}  # {"ip": "10.0.0.254/8"}
  59         # create the container and connect it to the given network
  60         d = self.net.addDocker("%s" % (name), dimage=image)
  61         self.net.addLink(d, self.switch, params1=network)
  62         self.containers[name] = d
  63         return name  # we might use UUIDs for naming later on
  64
  65     def removeCompute(self, name):
  66         """
  67         Stop and remove a container from this data center.
  68         """
  69         assert name in self.containers
  70         self.net.removeLink(
  71             link=None, node1=self.containers[name], node2=self.switch)
  72         self.net.removeDocker("%s" % (name))
  73         del self.containers[name]
  74         return True
  75
  76     def listCompute(self):
  77         """
  78         Return a list of all running containers assigned to this
  79         data center.
  80         """
  81         return self.containers.itervalues()