2 """The database houses information on slivers. This information
3 reaches the sliver manager in two different ways: one, through the
4 GetSlivers() call made periodically; two, by users delivering tickets.
5 The sync() method of the Database class turns this data into reality.
7 The database format is a dictionary that maps account names to records
8 (also known as dictionaries). Inside each record, data supplied or
9 computed locally is stored under keys that begin with an underscore,
10 and data from PLC is stored under keys that don't.
12 In order to maintain service when the node reboots during a network
13 partition, the database is constantly being dumped to disk.
26 # is there a good reason to have this done here and not in a plugin ?
27 try: from coresched_lxc import CoreSched
28 except: from coresched_vs import CoreSched
30 # We enforce minimum allocations to keep the clueless from hosing their slivers.
31 # Disallow disk loans because there's currently no way to punish slivers over quota.
32 MINIMUM_ALLOCATION = {'cpu_pct': 0,
40 LOANABLE_RESOURCES = MINIMUM_ALLOCATION.keys()
42 DB_FILE = '/var/lib/nodemanager/database.pickle'
45 # database object and associated lock
46 db_lock = threading.RLock()
49 # these are used in tandem to request a database dump from the dumper daemon
50 db_cond = threading.Condition(db_lock)
51 dump_requested = False
53 # decorator that acquires and releases the database lock before and after the decorated operation
54 # XXX - replace with "with" statements once we switch to 2.5
56 def sync_fn(*args, **kw_args):
58 try: return fn(*args, **kw_args)
59 finally: db_lock.release()
60 sync_fn.__doc__ = fn.__doc__
61 sync_fn.__name__ = fn.__name__
67 self._min_timestamp = 0
69 def _compute_effective_rspecs(self):
70 """Calculate the effects of loans and store the result in field _rspec.
71 At the moment, we allow slivers to loan only those resources that they have received directly from PLC.
72 In order to do the accounting, we store three different rspecs:
73 * field 'rspec', which is the resources given by PLC;
74 * field '_rspec', which is the actual amount of resources the sliver has after all loans;
75 * and variable resid_rspec, which is the amount of resources the sliver
76 has after giving out loans but not receiving any."""
78 for name, rec in self.iteritems():
80 rec['_rspec'] = rec['rspec'].copy()
82 for rec in slivers.itervalues():
83 eff_rspec = rec['_rspec']
84 resid_rspec = rec['rspec'].copy()
85 for target, resource_name, amount in rec.get('_loans', []):
86 if target in slivers and amount <= resid_rspec[resource_name] - MINIMUM_ALLOCATION[resource_name]:
87 eff_rspec[resource_name] -= amount
88 resid_rspec[resource_name] -= amount
89 slivers[target]['_rspec'][resource_name] += amount
91 def deliver_record(self, rec):
92 """A record is simply a dictionary with 'name' and 'timestamp'
93 keys. We keep some persistent private data in the records under keys
94 that start with '_'; thus record updates should not displace such
96 if rec['timestamp'] < self._min_timestamp: return
98 old_rec = self.get(name)
99 if old_rec == None: self[name] = rec
100 elif rec['timestamp'] > old_rec['timestamp']:
101 for key in old_rec.keys():
102 if not key.startswith('_'): del old_rec[key]
105 def set_min_timestamp(self, ts):
106 """The ._min_timestamp member is the timestamp on the last comprehensive update.
107 We use it to determine if a record is stale.
108 This method should be called whenever new GetSlivers() data comes in."""
109 self._min_timestamp = ts
110 for name, rec in self.items():
111 if rec['timestamp'] < ts: del self[name]
114 """Synchronize reality with the database contents. This
115 method does a lot of things, and it's currently called after every
116 single batch of database changes (a GetSlivers(), a loan, a record).
117 It may be necessary in the future to do something smarter."""
119 # delete expired records
121 for name, rec in self.items():
122 if rec.get('expires', now) < now: del self[name]
124 self._compute_effective_rspecs()
127 coresched = CoreSched()
128 coresched.adjustCores(self)
130 logger.log_exc("database: exception while doing core sched")
132 # create and destroy accounts as needed
133 logger.verbose("database: sync : fetching accounts")
134 existing_acct_names = account.all()
135 for name in existing_acct_names:
137 logger.verbose("database: sync : ensure_destroy'ing %s"%name)
138 account.get(name).ensure_destroyed()
139 for name, rec in self.iteritems():
140 # protect this; if anything fails for a given sliver
141 # we still need the other ones to be handled
143 sliver = account.get(name)
144 logger.verbose("database: sync : looping on %s (shell account class from pwd %s)" %(name,sliver._get_class()))
145 # Make sure we refresh accounts that are running
146 if rec['instantiation'] == 'plc-instantiated':
147 logger.verbose ("database: sync : ensure_create'ing 'instantiation' sliver %s"%name)
148 sliver.ensure_created(rec)
149 elif rec['instantiation'] == 'nm-controller':
150 logger.verbose ("database: sync : ensure_create'ing 'nm-controller' sliver %s"%name)
151 sliver.ensure_created(rec)
152 # Back door to ensure PLC overrides Ticket in delegation.
153 elif rec['instantiation'] == 'delegated' and sliver._get_class() != None:
154 # if the ticket has been delivered and the nm-controller started the slice
155 # update rspecs and keep them up to date.
156 if sliver.is_running():
157 logger.verbose ("database: sync : ensure_create'ing 'delegated' sliver %s"%name)
158 sliver.ensure_created(rec)
160 logger.log_exc("database: sync failed to handle sliver",name=name)
162 # Wake up bwmom to update limits.
164 global dump_requested
165 dump_requested = True
170 """The database dumper daemon.
171 When it starts up, it populates the database with the last dumped database.
172 It proceeds to handle dump requests forever."""
174 global dump_requested
177 while not dump_requested: db_cond.wait()
178 db_pickle = cPickle.dumps(db, cPickle.HIGHEST_PROTOCOL)
179 dump_requested = False
182 tools.write_file(DB_FILE, lambda f: f.write(db_pickle))
183 logger.log_database(db)
185 logger.log_exc("database.start: failed to pickle/dump")
189 try: db = cPickle.load(f)
192 logger.log ("database: Could not load %s -- starting from a fresh database"%DB_FILE)
195 logger.log_exc("database: failed in start")
197 logger.log('database.start')
198 tools.as_daemon_thread(run)