def __init__(self, zkobj, this_ip, this_url, config):
super(DockerManager, self).__init__()
self.zkobj = zkobj and zkobj._cast_as(Docker)
self.this_ip = this_ip
self.this_url = this_url
self.config = config
self.uuid = str(uuid.uuid4())
self.used_slots = 0
self.scheduler_cache = {}
self.image_cond = threading.Condition()
self.images = {}
self._containers = Cache(self.zkobj.containers(), update=self._delete)
self._to_start = Cache(self.zkobj.to_start(), update=self._start)
self._starting = self.zkobj.starting()
self._scheduler_info = Cache(self.zkobj.scheduler_info(), update=self._notify_scheduler)
self._load()
self._update_scheduler_info()
class DockerManager(object):
def __init__(self, zkobj, this_ip, this_url, config):
super(DockerManager, self).__init__()
self.zkobj = zkobj and zkobj._cast_as(Docker)
self.this_ip = this_ip
self.this_url = this_url
self.config = config
self.uuid = str(uuid.uuid4())
self.used_slots = 0
self.scheduler_cache = {}
self.image_cond = threading.Condition()
self.images = {}
self._containers = Cache(self.zkobj.containers(), update=self._delete)
self._to_start = Cache(self.zkobj.to_start(), update=self._start)
self._starting = self.zkobj.starting()
self._scheduler_info = Cache(self.zkobj.scheduler_info(), update=self._notify_scheduler)
self._load()
self._update_scheduler_info()
def _extract_ip(self, instance_id):
try:
# Extract the private port.
instance_info = self.config.client().inspect_container(instance_id)
network_info = instance_info["NetworkSettings"]
if network_info != None and network_info.get("Ports"):
# This handles the case for Docker >= 0.6.5.
tcp_ports = network_info.get("Ports").items()
if tcp_ports and len(tcp_ports) > 0:
private_port = tcp_ports[0][1][0].get("HostPort")
return '%s:%s' % (self.this_ip, private_port)
elif network_info != None and network_info.get("PortMapping"):
# This handles the case for Docker < 0.6.5.
tcp_ports = network_info["PortMapping"].get("Tcp")
if tcp_ports and len(tcp_ports) > 0:
private_port = tcp_ports.items()[0][1]
return '%s:%s' % (self.this_ip, private_port)
except Exception:
traceback.print_exc()
# No port available.
# Unfortunately this means this isn't
# a running instance and we will kill it.
return None
def _load(self):
# Check that our instances match expectations.
for instance_id in map(lambda x: x['Id'][:12],
self.config.client().containers(all=True)):
# Is it one of ours?
try:
instance_info = self.config.client().inspect_container(instance_id)
except Exception:
traceback.print_exc()
continue
env = instance_info['Config']['Env']
if env != None:
env = dict(map(lambda x: x.split("=", 1), env))
if SLOTS_ENVIRONMENT_KEY in env:
if instance_id in self._containers.list():
# NOTE: We update the IP here as well because it
# may have changed if this was a reboot event or
# something similar.
ip_address = self._extract_ip(instance_id)
self.used_slots += int(env[SLOTS_ENVIRONMENT_KEY])
if ip_address:
# Reset the IP address in the store.
self._containers.add(
instance_id, ip_address, mustexist=True)
else:
# No need to do any accounting here.
self.config.client().kill(instance_id)
self.config.client().remove_container(instance_id)
# Clean out non-running instances.
# NOTE: This duplicates a lot of the functionality
# above, but it's important to ensure that we get
# the accounting correct.
self._delete()
def _notify_scheduler(self):
# Update scheduler information. Either a new
# instance has been started, or a new server
# has come online, or some combination.
if hasattr(self, '_scheduler_info'):
self.scheduler_cache = self._scheduler_info.as_map()
# We've changed scheduler info, so we'd best
# rerun our schedule() function and ensure that
# everything gets scheduled.
self._start()
def _update_scheduler_info(self):
# Update our scheduler information.
# NOTE: This will generate _notify_scheduler()
# asynchronously, so there's no need to call it.
self._scheduler_info.add(self.uuid,
(self.used_slots, self.config.slots), ephemeral=True)
def instances(self):
# Clean up all the dead containers.
# We don't care about failure here, as
# this is just a best effort call.
try:
self._delete()
except Exception:
pass
# List the aggregate of all servers.
return self._containers.as_map()
def start(self, config, timeout=10.0, params=None):
# Submit a scheduling request.
# We do so by writing the uuid to
# a unique node in the to_start pool.
# This will be picked up by the a
# server that thinks it has the most
# (relative) slots available.
start = time.time()
this_uuid = str(uuid.uuid4())
# Serialize the configuration.
# This installs an ephermal node in Zookeeper
# (basically as an RPC entry) which will fire
# appropriately when it is changed.
self._to_start.add(this_uuid, config._values(), ephemeral=True)
ref = self._to_start._get_child(this_uuid, clazz=JSONObject)
try:
cond = threading.Condition()
def _notify(value):
cond.acquire()
cond.notifyAll()
cond.release()
cond.acquire()
instance_info = ref._get_data(watch=_notify)
try:
while True:
# Check if we're set.
# This is a pretty loose system for
# RPC, where we know the result is either
# a tuple (the result), an exception (str)
# or the original dictionary configuration.
if isinstance(instance_info, str):
# Shit, an exception on the other end.
raise Exception(instance_info)
elif isinstance(instance_info, dict):
# Still our configuration, waiting.
pass
else:
# Successfully spawned.
return instance_info
# Check if we're out of time.
now = time.time()
if now >= start + timeout:
break
# Wait for a notification and refresh.
cond.wait(start + timeout - now)
instance_info = ref._get_data()
finally:
cond.release()
finally:
ref._delete()
# No success.
raise Exception("timed out")
def _spawn(self, config):
# Ensure that this image is available.
self._pull(config.image)
# Figure out the right port.
# NOTE: This is derived from the endpoint.
if config.port():
port_key = "%s/tcp" % (config.port(),)
ports = {}
ports[port_key] = {}
port_bindings = {}
port_bindings[port_key] = [{'HostIp': '', 'HostPort': ''}]
else:
ports = None
port_bindings = None
# Add the slots to the environment.
env = config.get_environment()
env[SLOTS_ENVIRONMENT_KEY] = str(config.slots)
# Add the reactor URL to the environment.
env[REACTOR_ENVIRONMENT_KEY] = str(self.this_url)
# Create the container.
instance_info = self.config.client().create_container(
config.image,
config.command,
hostname=config.hostname or None,
user=config.user or None,
detach=True,
stdin_open=False,
tty=False,
mem_limit=config.mem_limit or None,
ports=ports,
environment=env,
dns=config.dns or None,
privileged=False)
# Grab the id to work with here.
instance_id = instance_info['Id'][:12]
# Start the container.
try:
# This will work well for Docker >= 0.6.5.
self.config.client().start(instance_id, port_bindings=port_bindings)
except TypeError:
# If port_bindings is not a known key, then assume Docker < 0.6.5.
self.config.client().start(instance_id)
# Grab the local IP for mapping.
ip_address = self._extract_ip(instance_id)
# Off to the races.
return (instance_id, config.slots, ip_address)
def _pull(self, image):
self.image_cond.acquire()
try:
# Wait while pending.
while self.images.has_key(image) and \
not self.images[image]:
self.image_cond.wait()
# Start the request.
self.images[image] = False
self.config.client().pull(image)
# Success.
self.images[image] = True
except Exception:
del self.images[image]
raise
finally:
self.image_cond.notifyAll()
self.image_cond.release()
def _start(self, clean_uuid=None):
# Check for an early notification.
if not hasattr(self, '_to_start'):
return
# Read all instances waiting to be scheduled.
for (this_uuid, config) in self._to_start.as_map().items():
# This is a result or something else.
# Will eventually be pruned (ephemeral)
# or removed by the caller.
if not isinstance(config, dict):
continue
# Get the config.
# This is currently a hack that is required to
# break the circular reference between the manager and
# the connection. If there is a reference, then neither
# the manager nor the connection will ever be cleaned up.
config = DockerEndpointConfig(values=config, section='cloud:docker')
# Figure out if we should schedule this one.
# We do this by figuring out which host will
# have the least slot used by *percentage*
# after the process is completed.
min_used = 1.0
best_hosts = []
for (host_uuid, (used_slots, total_slots)) in self.scheduler_cache.items():
this_used = float(used_slots + config.slots) / total_slots
if this_used < min_used:
min_used = this_used
best_hosts = [host_uuid]
elif this_used == min_used:
best_hosts.append(host_uuid)
# Are we a candidate?
if self.uuid in best_hosts:
if self._starting.lock([this_uuid]):
try:
# First, do the actual launch and update
# our scheduling information so people can
# make the right decisions.
(instance_id, slots, ip_address) = self._spawn(config)
self.used_slots += slots
self._update_scheduler_info()
# Finally add the container to the list of
# containers and return to the caller.
if self._to_start.add(this_uuid,
(instance_id, ip_address), mustexist=True):
self._containers.add(instance_id, ip_address)
except Exception, e:
# Write the result out as an exception.
self._to_start.add(this_uuid, (str(e),), mustexist=True)
finally:
# Always clear the lock.
self._starting.remove(this_uuid)
