Merge "Add enable_new_agents to neutron server"

specs/liberty/enable-new-agents.rst

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+..
+ This work is licensed under a Creative Commons Attribution 3.0 Unported
+ License.
+
+ http://creativecommons.org/licenses/by/3.0/legalcode
+
+==========================================
+Add enable_new_agents to neutron server
+==========================================
+
+https://blueprints.launchpad.net/neutron/+spec/enable-new-agents
+
+This proposal adds enable_new_agents config for operator maintenance to agents
+in network node. It proposes a way that an agent can start without selectable
+for auto-scheduling but manual-scheduling available so that a deployer can test
+an agent manually.
+
+Problem Description
+===================
+
+Neutron doesn't have a way to test a newly added network node by deploying test
+resource before any customer resource on the node is deployed. When cloud
+operators control network resources, they want to prevent users from
+controlling the resources. For example, they may try to create test resources
+on a new node while deploying the new node. Neutron can prevent users from
+creating the resources on the node by agent's admin_state_up=False, but Neutron
+cannot start agent with admin_state_up=False. Neutron always starts agent with
+admin_state_up=True. Nova and Cinder have the setting of "enable_new_services"
+in each conf to disable the initial service status to achieve this.
+
+Neutron also has a problem for the maintenance scenario. Neutron can
+prevent all users from creating the resources on the agent with
+admin_state_up=False, but Neutron usually cannot allow admin user only
+to create the resources. Currently, if
+enable_services_on_agents_with_admin_state_down configuration
+parameter is True, admin can create the resources on the agent.
+
+Proposed Change
+===============
+
+This proposal adds enable_new_agents config for operator maintenance to agents
+in network nodes. Neutron agent's admin_state_up is controlled by this config
+while starting. The config is added to neutron-server since the proposal provides
+all agents which have scheduling method(i.e.l3-agent, dhcp-agent, lbaas-agent)
+and don't have the method(i.e. ovs-agent, metadata-agent) so that deployers
+enable agents easily although this proposal gives a benefit to scheduling agents
+only.
+
+* Neutron agent starts with admin_state_up=True when enable_new_agents=True.
+  This behaviour is default. User freely creates their resources on the agent.
+
+* Neutron agent starts with admin_state_up=False when enable_new_agents=False.
+  This behaviour is maintenance mode. In the case, user's resources cannot be
+  created on the agent until admin changes admin_state_up to True.
+
+The default value is True because this proposal doesn't intend to change a
+traditional behaviour.
+
+The proposal also presupposes that
+enable_services_on_agents_with_admin_state_down is True in Neutron
+servers.
+
+Data Model Impact
+-----------------
+
+None
+
+REST API Impact
+---------------
+
+None
+
+Security Impact
+---------------
+
+None
+
+Notifications Impact
+--------------------
+
+None
+
+Other End User Impact
+---------------------
+
+None
+
+Performance Impact
+------------------
+
+None
+
+IPv6 Impact
+-----------
+
+None
+
+Other Deployer Impact
+---------------------
+
+This proposal adds enable_new_agents to neutron.conf. This config is set True
+as default value. It doesn't change a traditional behaviour of the agents.
+
+Developer Impact
+----------------
+
+None
+
+Community Impact
+----------------
+
+None
+
+Alternatives
+------------
+
+None
+
+Implementation
+==============
+
+Assignee(s)
+-----------
+
+Hirofumi Ichihara <ichihara-hirofumi>
+
+Work Items
+----------
+
+* Add enable_new_agents config and the implements
+
+Dependencies
+============
+
+None
+
+Testing
+=======
+
+Tempest Tests
+-------------
+
+None
+
+Functional Tests
+----------------
+
+Add tests which ensure agents start with admin_state_up False.
+
+API Tests
+---------
+
+None
+
+Documentation Impact
+====================
+
+User Documentation
+------------------
+
+The new config options will be documented.
+
+The following is a maintenance scenario. The maintenance scenario will be
+documented.
+
+Precondition: Neutron servers run with
+enable_services_on_agents_with_admin_state_down=True.
+
+1. Admin prepares a new network node.
+2. Admin adds enable_new_agents=False to neutron.conf and starts a neutron
+   server, then their all agents.
+3. All agents run with admin_state_up=False.
+4. Admin needs to create a network (or router) and allocates it to a target
+   agent.
+5. Admin creates VM connected the network resources, then admin
+   confirms the capability.
+6. Admin deletes all resources and update agents to be
+   admin_state_up=True after the test.
+
+Developer Documentation
+-----------------------
+
+None
+
+References
+==========
+
+* https://blueprints.launchpad.net/neutron/+spec/enable-new-agents
+* http://lists.openstack.org/pipermail/openstack-operators/2015-March/006434.html