def find_candidate_subnets(cls,
context,
network_id,
host,
service_type,
fixed_configured,
fixed_ips,
distributed_service=False):
"""Find canditate subnets for the network, host, and service_type"""
query = cls.query_subnets_on_network(context, network_id)
query = SubnetServiceType.query_filter_service_subnets(
query, service_type)
# Select candidate subnets and return them
if not cls.is_host_set(host):
if fixed_configured:
# If fixed_ips in request and host is not known all subnets on
# the network are candidates. Host/Segment will be validated
# on port update with binding:host_id set. Allocation _cannot_
# be deferred as requested fixed_ips would then be lost.
return cls._query_filter_by_fixed_ips_segment(
query,
fixed_ips,
allow_multiple_segments=distributed_service).all()
# If the host isn't known, we can't allocate on a routed network.
# So, exclude any subnets attached to segments.
return cls._query_exclude_subnets_on_segments(query).all()
# The host is known. Consider both routed and non-routed networks
results = cls._query_filter_by_segment_host_mapping(query, host).all()
# For now, we're using a simplifying assumption that a host will only
# touch one segment in a given routed network. Raise exception
# otherwise. This restriction may be relaxed as use cases for multiple
# mappings are understood.
segment_ids = {
subnet.segment_id
for subnet, mapping in results if mapping
}
if 1 < len(segment_ids):
raise segment_exc.HostConnectedToMultipleSegments(
host=host, network_id=network_id)
return [subnet for subnet, _mapping in results]
def _ipam_get_subnets(self, context, network_id, host):
Subnet = models_v2.Subnet
SegmentHostMapping = segment_svc_db.SegmentHostMapping
query = self._get_collection_query(context, Subnet)
query = query.filter(Subnet.network_id == network_id)
# Note: This seems redundant, but its not. It has to cover cases
# where host is None, ATTR_NOT_SPECIFIED, or '' due to differences in
# host binding implementations.
if not validators.is_attr_set(host) or not host:
query = query.filter(Subnet.segment_id.is_(None))
return [self._make_subnet_dict(c, context=context) for c in query]
# A host has been provided. Consider these two scenarios
# 1. Not a routed network: subnets are not on segments
# 2. Is a routed network: only subnets on segments mapped to host
# The following join query returns results for either. The two are
# guaranteed to be mutually exclusive when subnets are created.
query = query.add_entity(SegmentHostMapping)
query = query.outerjoin(
SegmentHostMapping,
and_(Subnet.segment_id == SegmentHostMapping.segment_id,
SegmentHostMapping.host == host))
# Essentially "segment_id IS NULL XNOR host IS NULL"
query = query.filter(
or_(
and_(Subnet.segment_id.isnot(None),
SegmentHostMapping.host.isnot(None)),
and_(Subnet.segment_id.is_(None),
SegmentHostMapping.host.is_(None))))
results = query.all()
# See if results are empty because the host isn't mapped to a segment
if not results:
# Check if it's a routed network (i.e subnets on segments)
query = self._get_collection_query(context, Subnet)
query = query.filter(Subnet.network_id == network_id)
query = query.filter(Subnet.segment_id.isnot(None))
if query.count() == 0:
return []
# It is a routed network but no subnets found for host
raise segment_exc.HostNotConnectedToAnySegment(
host=host, network_id=network_id)
# For now, we're using a simplifying assumption that a host will only
# touch one segment in a given routed network. Raise exception
# otherwise. This restriction may be relaxed as use cases for multiple
# mappings are understood.
segment_ids = {
subnet.segment_id
for subnet, mapping in results if mapping
}
if 1 < len(segment_ids):
raise segment_exc.HostConnectedToMultipleSegments(
host=host, network_id=network_id)
return [
self._make_subnet_dict(subnet, context=context)
for subnet, _mapping in results
]
