openstack/neutron
Code Issues Proposed changes

Dont schedule Network, respecting network_auto_schedule config

Browse Source 
Currently, if dhcp mapping from a network is removed, it is reassigned
to the network. This is because of the Network Scheduler's schedule
function, which considers balancing the networks with the agents, whether
enable_dhcp is set on its subnets or not. It does not take into account
the network_auto_schedule config option. This is particularly disturbing
when considering backends which have their provide their own DHCP.

With this patch, if network_auto_schedule is set to False, networks wont
be automatically scheduled to DHCP Agents. If DHCP is to be mapped to a
network, it can be mapped using the CLI itself.

While it may seem that this change is breaking what is already working,
but as mentioned earlier, if there are network backends which provide DHCP
support themselves, they wont need the automatic mapping, which the term
"network_auto_schedule" actually stands for.

Closes-Bug: #1647421
Change-Id: If1a6a2a174d0f737415efa2abce518722316a77b
This commit is contained in:
Reedip 2019-11-11 10:54:42 +09:00
parent d15ad2e481
commit 139b496ef9
3 changed files with 44 additions and 1 deletions
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2
neutron/db/agentschedulers_db.py
View File

@ -475,7 +475,7 @@ class DhcpAgentSchedulerDbMixin(dhcpagentscheduler
return {'agents': []}
def schedule_network(self, context, created_network):
if self.network_scheduler:
if self.network_scheduler and cfg.CONF.network_auto_schedule:
return self.network_scheduler.schedule(
self, context, created_network)

29
neutron/tests/unit/db/test_agentschedulers_db.py
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@ -1354,6 +1354,35 @@ class OvsAgentSchedulerTestCase(OvsAgentSchedulerTestCaseBase):
self._list_networks_hosted_by_dhcp_agent(invalid_agentid,
exc.HTTPNotFound.code)
def test_network_no_reschedule(self):
cfg.CONF.set_override('allow_overlapping_ips', True)
cfg.CONF.set_override('network_auto_schedule', False)
with self.subnet() as sb1, self.subnet():
network1_id = sb1['subnet']['network_id']
dhcp_rpc_cb = dhcp_rpc.DhcpRpcCallback()
self._register_agent_states()
hosta_id = self._get_agent_id(constants.AGENT_TYPE_DHCP,
DHCP_HOSTA)
hostc_id = self._get_agent_id(constants.AGENT_TYPE_DHCP,
DHCP_HOSTC)
dhcp_rpc_cb.get_active_networks_info(
self.adminContext, host=DHCP_HOSTA)
dhcp_rpc_cb.get_active_networks_info(
self.adminContext, host=DHCP_HOSTC)
networks = self._list_networks_hosted_by_dhcp_agent(hostc_id)
num_hostc_nets = len(networks['networks'])
networks = self._list_networks_hosted_by_dhcp_agent(hosta_id)
num_hosta_nets = len(networks['networks'])
self.assertEqual(0, num_hosta_nets)
self.assertEqual(0, num_hostc_nets)
# After this patch, network which requires DHCP
# has to be manually mapped
self._add_network_to_dhcp_agent(hosta_id,
network1_id)
networks = self._list_networks_hosted_by_dhcp_agent(hosta_id)
num_hosta_nets = len(networks['networks'])
self.assertEqual(1, num_hosta_nets)
class OvsDhcpAgentNotifierTestCase(test_agent.AgentDBTestMixIn,
AgentSchedulerTestMixIn,

14
releasenotes/notes/modify-dhcp-behavior-based-on-network-auto-schedule-1ea5e74fd5bb560c.yaml Normal file
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@ -0,0 +1,14 @@
---
fixes:
- |
Neutron currently does not fully respect the network-auto-schedule
configuration option. If the network-auto-schedule option is set to
False, the network -
a) Is still scheduled on the DHCP agent when it is created
b) Is scheduled on a new DHCP agent if the old DHCP mapping is removed
by the user/admin.
It is especially necessary where the Network Backends provide DHCP
directly. This has been fixed now and if the network-auto-schedule
is set to False in the config file, networks would not be automatically
scheduled to the DHCP Agents. If mapping/scheduling is required, it can
be done manually or by setting the network-auto-schedule to True.