I have observed that my ipavailability ranges have not been reset after the pool has run out using the dashboard. I have deleted several of my instances and still a previously used fixed ip is not assigned, resulting in a failure of the launch. 

Part of the neutron log:

2015-05-20 08:04:50.331 3533 INFO neutron.wsgi [req-fe796412-e796-4c08-a798-ab520dbdeb91 None] 10.173.3.13 - - [20/May/2015 08:04:50] "GET /v2.0/security-groups.json?tenant_id=8df11859bd554dc4bc3d6b7f824cf5d6 HTTP/1.1" 200 2433 0.068064
2015-05-20 08:04:50.340 3561 INFO neutron.wsgi [-] (3561) accepted ('10.173.3.13', 57650)
2015-05-20 08:04:50.341 3561 DEBUG keystonemiddleware.auth_token [-] Removing headers from request environment: X-Service-Catalog,X-Identity-Status,X-Roles,X-Service-Roles,X-Domain-Name,X-Service-Domain-Name,X-Project-Id,X-Service-Project-Id,X-Project-Domain-Name,X-Service-Project-Domain-Name,X-User-Id,X-Service-User-Id,X-User-Name,X-Service-User-Name,X-Project-Name,X-Service-Project-Name,X-User-Domain-Id,X-Service-User-Domain-Id,X-Domain-Id,X-Service-Domain-Id,X-User-Domain-Name,X-Service-User-Domain-Name,X-Project-Domain-Id,X-Service-Project-Domain-Id,X-Role,X-User,X-Tenant-Name,X-Tenant-Id,X-Tenant _remove_auth_headers /usr/lib/python2.7/site-packages/keystonemiddleware/auth_token.py:780
2015-05-20 08:04:50.341 3561 DEBUG keystonemiddleware.auth_token [-] Authenticating user token __call__ /usr/lib/python2.7/site-packages/keystonemiddleware/auth_token.py:708
2015-05-20 08:04:50.342 3561 DEBUG keystonemiddleware.auth_token [-] Returning cached token _cache_get /usr/lib/python2.7/site-packages/keystonemiddleware/auth_token.py:1793
2015-05-20 08:04:50.343 3561 DEBUG keystonemiddleware.auth_token [-] Authenticating service token __call__ /usr/lib/python2.7/site-packages/keystonemiddleware/auth_token.py:727
2015-05-20 08:04:50.343 3561 DEBUG keystonemiddleware.auth_token [-] Received request from user: user_id None, project_id None, roles None service: user_id None, project_id None, roles None __call__ /usr/lib/python2.7/site-packages/keystonemiddleware/auth_token.py:746
2015-05-20 08:04:50.343 3561 DEBUG routes.middleware [req-58b7ee85-3cb6-4ae2-95e8-b4be0fcb062c ] No route matched for POST /ports.json __call__ /usr/lib/python2.7/site-packages/routes/middleware.py:97
2015-05-20 08:04:50.344 3561 DEBUG routes.middleware [req-58b7ee85-3cb6-4ae2-95e8-b4be0fcb062c ] Matched POST /ports.json __call__ /usr/lib/python2.7/site-packages/routes/middleware.py:100
2015-05-20 08:04:50.344 3561 DEBUG routes.middleware [req-58b7ee85-3cb6-4ae2-95e8-b4be0fcb062c ] Route path: '/ports{.format}', defaults: {'action': u'create', 'controller': <wsgify at 57778640 wrapping <function resource at 0x3881230>>} __call__ /usr/lib/python2.7/site-packages/routes/middleware.py:102
2015-05-20 08:04:50.344 3561 DEBUG routes.middleware [req-58b7ee85-3cb6-4ae2-95e8-b4be0fcb062c ] Match dict: {'action': u'create', 'controller': <wsgify at 57778640 wrapping <function resource at 0x3881230>>, 'format': u'json'} __call__ /usr/lib/python2.7/site-packages/routes/middleware.py:103
2015-05-20 08:04:50.348 3561 DEBUG neutron.api.v2.base [req-58b7ee85-3cb6-4ae2-95e8-b4be0fcb062c None] Request body: {u'port': {u'binding:host_id': u'r001ds03.pcs', u'admin_state_up': True, u'network_id': u'5835a57c-f02b-414c-9a10-2250ce90a230', u'tenant_id': u'8df11859bd554dc4bc3d6b7f824cf5d6', u'device_owner': u'compute:None', u'security_groups': [u'ee972078-d846-4755-abfd-7ed06669e376'], u'device_id': u'5359b81d-aeda-41f9-8d00-6516e048b0e9'}} prepare_request_body /usr/lib/python2.7/site-packages/neutron/api/v2/base.py:582
2015-05-20 08:04:50.349 3561 DEBUG neutron.policy [req-58b7ee85-3cb6-4ae2-95e8-b4be0fcb062c None] Enforcing rules: ['create_port', 'create_port:binding:host_id'] _build_match_rule /usr/lib/python2.7/site-packages/neutron/policy.py:221
2015-05-20 08:04:50.380 3561 DEBUG neutron.db.db_base_plugin_v2 [req-58b7ee85-3cb6-4ae2-95e8-b4be0fcb062c None] Generated mac for network 5835a57c-f02b-414c-9a10-2250ce90a230 is fa:16:3e:0f:0f:f3 _generate_mac /usr/lib/python2.7/site-packages/neutron/db/db_base_plugin_v2.py:144
2015-05-20 08:04:50.380 3561 DEBUG neutron.notifiers.nova [req-58b7ee85-3cb6-4ae2-95e8-b4be0fcb062c None] Ignoring state change previous_port_status: symbol('NO_VALUE') current_port_status: DOWN port_id 57bb6f4f-d5bd-491c-a3c8-de672386a58a record_port_status_changed /usr/lib/python2.7/site-packages/neutron/notifiers/nova.py:211
2015-05-20 08:04:50.391 3561 DEBUG neutron.db.db_base_plugin_v2 [req-58b7ee85-3cb6-4ae2-95e8-b4be0fcb062c None] All IPs from subnet 948021ac-a8de-434c-9310-9aecec158fa2 (202.1.102.0/24) allocated _try_generate_ip /usr/lib/python2.7/site-packages/neutron/db/db_base_plugin_v2.py:221
2015-05-20 08:04:50.392 3561 DEBUG neutron.db.db_base_plugin_v2 [req-58b7ee85-3cb6-4ae2-95e8-b4be0fcb062c None] Rebuilding availability ranges for subnet {'name': u'my_subnet', 'enable_dhcp': True, 'network_id': u'5835a57c-f02b-414c-9a10-2250ce90a230', 'tenant_id': u'8df11859bd554dc4bc3d6b7f824cf5d6', 'dns_nameservers': [u'192.168.60.11'], 'gateway_ip': u'202.1.102.1', 'ipv6_ra_mode': None, 'allocation_pools': [{'start': u'202.1.102.10', 'end': u'202.1.102.15'}], 'host_routes': [], 'shared': False, 'ip_version': 4L, 'ipv6_address_mode': None, 'cidr': u'202.1.102.0/24', 'id': u'948021ac-a8de-434c-9310-9aecec158fa2'} _rebuild_availability_ranges /usr/lib/python2.7/site-packages/neutron/db/db_base_plugin_v2.py:261
2015-05-20 08:04:50.395 3561 DEBUG neutron.db.db_base_plugin_v2 [req-58b7ee85-3cb6-4ae2-95e8-b4be0fcb062c None] All IPs from subnet 948021ac-a8de-434c-9310-9aecec158fa2 (202.1.102.0/24) allocated _try_generate_ip /usr/lib/python2.7/site-packages/neutron/db/db_base_plugin_v2.py:221
2015-05-20 08:04:50.396 3561 INFO neutron.api.v2.resource [req-58b7ee85-3cb6-4ae2-95e8-b4be0fcb062c None] create failed (client error): No more IP addresses available on network 5835a57c-f02b-414c-9a10-2250ce90a230.
2015-05-20 08:04:50.397 3561 INFO neutron.wsgi [req-58b7ee85-3cb6-4ae2-95e8-b4be0fcb062c None] 10.173.3.13 - - [20/May/2015 08:04:50] "POST /v2.0/ports.json HTTP/1.1" 409 360 0.055838