def _schedule_bigiq_agent(self, context, loadbalancer_id, active=True):
# TODO: agent scheduler
query = context.session.query(agents_db.Agent)
query = query.filter_by(agent_type=constants.LBAASV2_BIGIQ_AGENT_TYPE,
admin_state_up=active)
agents = [agent for agent in query]
if len(agents) > 0:
# Bind loadbalancer with agent
binding = agent_scheduler.LoadbalancerAgentBinding()
binding.agent = agents[0]
binding.loadbalancer_id = loadbalancer_id
context.session.add(binding)
return agents[0]
else:
raise exceptions.NoEligibleBIGIQAgent(
loadbalancer_id=loadbalancer_id
)
def schedule(self, plugin, context, loadbalancer_id, env=None):
"""Schedule the loadbalancer to an active loadbalancer agent.
If there is no enabled agent hosting it.
"""
with context.session.begin(subtransactions=True):
loadbalancer = plugin.db.get_loadbalancer(context, loadbalancer_id)
# If the loadbalancer is hosted on an active agent
# already, return that agent or one in its env
lbaas_agent = self.get_lbaas_agent_hosting_loadbalancer(
plugin,
context,
loadbalancer.id,
env
)
if lbaas_agent:
lbaas_agent = lbaas_agent['agent']
LOG.debug(' Assigning task to agent %s.'
% (lbaas_agent['id']))
return lbaas_agent
# There is no existing loadbalancer agent binding.
# Find all active agent candidates in this env.
# We use environment_prefix to find F5® agents
# rather then map to the agent binary name.
candidates = self.get_agents_in_env(
context,
plugin,
env,
active=True
)
LOG.debug("candidate agents: %s", candidates)
if len(candidates) == 0:
LOG.error('No f5 lbaas agents are active for env %s' % env)
raise lbaas_agentschedulerv2.NoActiveLbaasAgent(
loadbalancer_id=loadbalancer.id)
# We have active candidates to choose from.
# Qualify them by tenant affinity and then capacity.
chosen_agent = None
agents_by_group = defaultdict(list)
capacity_by_group = {}
for candidate in candidates:
# Organize agents by their environment group
# and collect each group's max capacity.
ac = self.deserialize_agent_configurations(
candidate['configurations']
)
gn = 1
if 'environment_group_number' in ac:
gn = ac['environment_group_number']
agents_by_group[gn].append(candidate)
# populate each group's capacity
group_capacity = self.get_capacity(ac)
if gn not in capacity_by_group:
capacity_by_group[gn] = group_capacity
else:
if group_capacity > capacity_by_group[gn]:
capacity_by_group[gn] = group_capacity
# Do we already have this tenant assigned to this
# agent candidate? If we do and it has capacity
# then assign this loadbalancer to this agent.
assigned_lbs = plugin.db.list_loadbalancers_on_lbaas_agent(
context, candidate['id'])
for assigned_lb in assigned_lbs:
if loadbalancer.tenant_id == assigned_lb.tenant_id:
chosen_agent = candidate
break
if chosen_agent:
# Does the agent which had tenants assigned
# to it still have capacity?
if group_capacity >= 1.0:
chosen_agent = None
else:
break
# If we don't have an agent with capacity associated
# with our tenant_id, let's pick an agent based on
# the group with the lowest capacity score.
if not chosen_agent:
# lets get an agent from the group with the
# lowest capacity score
lowest_utilization = 1.0
selected_group = 1
for group, capacity in capacity_by_group.items():
if capacity < lowest_utilization:
lowest_utilization = capacity
selected_group = group
LOG.debug('%s group %s scheduled with capacity %s'
% (env, selected_group, lowest_utilization))
if lowest_utilization < 1.0:
# Choose a agent in the env group for this
# tenant at random.
chosen_agent = random.choice(
agents_by_group[selected_group]
)
# If there are no agents with available capacity, raise exception
if not chosen_agent:
LOG.warn('No capacity left on any agents in env: %s' % env)
LOG.warn('Group capacity in environment %s were %s.'
% (env, capacity_by_group))
raise lbaas_agentschedulerv2.NoEligibleLbaasAgent(
loadbalancer_id=loadbalancer.id)
binding = agent_scheduler.LoadbalancerAgentBinding()
binding.agent = chosen_agent
binding.loadbalancer_id = loadbalancer.id
context.session.add(binding)
LOG.debug(('Loadbalancer %(loadbalancer_id)s is scheduled to '
'lbaas agent %(agent_id)s'),
{'loadbalancer_id': loadbalancer.id,
'agent_id': chosen_agent['id']})
return chosen_agent