Merge "Concurrent Distructive/Intensive ops limits"

9 files changed, 287 insertions, 4 deletions

diff --git a/doc/source/admin/troubleshooting.rst b/doc/source/admin/troubleshooting.rst
index fa04d3006..2791430fd 100644
--- a/doc/source/admin/troubleshooting.rst
+++ b/doc/source/admin/troubleshooting.rst
@@ -973,3 +973,40 @@ Unfortunately, due to the way the conductor is designed, it is not possible to
 gracefully break a stuck lock held in ``*-ing`` states. As the last resort, you
 may need to restart the affected conductor. See `Why are my nodes stuck in a
 "-ing" state?`_.
+
+What is ConcurrentActionLimit?
+==============================
+
+ConcurrentActionLimit is an exception which is raised to clients when an
+operation is requested, but cannot be serviced at that moment because the
+overall threshold of nodes in concurrent "Deployment" or "Cleaning"
+operations has been reached.
+
+These limits exist for two distinct reasons.
+
+The first is they allow an operator to tune a deployment such that too many
+concurrent deployments cannot be triggered at any given time, as a single
+conductor has an internal limit to the number of overall concurrent tasks,
+this restricts only the number of running concurrent actions. As such, this
+accounts for the number of nodes in ``deploy`` and ``deploy wait`` states.
+In the case of deployments, the default value is relatively high and should
+be suitable for *most* larger operators.
+
+The second is to help slow down the ability in which an entire population of
+baremetal nodes can be moved into and through cleaning, in order to help
+guard against authenticated malicious users, or accidental script driven
+operations. In this case, the total number of nodes in ``deleting``,
+``cleaning``, and ``clean wait`` are evaluated. The default maximum limit
+for cleaning operations is *50* and should be suitable for the majority of
+baremetal operators.
+
+These settings can be modified by using the
+``[conductor]max_concurrent_deploy`` and ``[conductor]max_concurrent_clean``
+settings from the ironic.conf file supporting the ``ironic-conductor``
+service. Neither setting can be explicity disabled, however there is also no
+upper limit to the setting.
+
+.. note::
+   This was an infrastructure operator requested feature from actual lessons
+   learned in the operation of Ironic in large scale production. The defaults
+   may not be suitable for the largest scale operators.
diff --git a/ironic/common/exception.py b/ironic/common/exception.py
index ddbce6f47..38316d2e7 100644
--- a/ironic/common/exception.py
+++ b/ironic/common/exception.py
@@ -851,3 +851,13 @@ class ImageRefIsARedirect(IronicException):
             message=msg,
             image_ref=image_ref,
             redirect_url=redirect_url)
+
+
+class ConcurrentActionLimit(IronicException):
+    # NOTE(TheJulia): We explicitly don't report the concurrent
+    # action limit configuration value as a security guard since
+    # if informed of the limit, an attacker can tailor their attack.
+    _msg_fmt = _("Unable to process request at this time. "
+                 "The concurrent action limit for %(task_type)s "
+                 "has been reached. Please contact your administrator "
+                 "and try again later.")
diff --git a/ironic/conductor/manager.py b/ironic/conductor/manager.py
index 13d11d1d9..7e98459ff 100644
--- a/ironic/conductor/manager.py
+++ b/ironic/conductor/manager.py
@@ -886,7 +886,8 @@ class ConductorManager(base_manager.BaseConductorManager):
                                    exception.NodeInMaintenance,
                                    exception.InstanceDeployFailure,
                                    exception.InvalidStateRequested,
-                                   exception.NodeProtected)
+                                   exception.NodeProtected,
+                                   exception.ConcurrentActionLimit)
     def do_node_deploy(self, context, node_id, rebuild=False,
                        configdrive=None, deploy_steps=None):
         """RPC method to initiate deployment to a node.
@@ -910,8 +911,11 @@ class ConductorManager(base_manager.BaseConductorManager):
         :raises: InvalidStateRequested when the requested state is not a valid
                  target from the current state.
         :raises: NodeProtected if the node is protected.
+        :raises: ConcurrentActionLimit if this action would exceed the maximum
+                 number of configured concurrent actions of this type.
         """
         LOG.debug("RPC do_node_deploy called for node %s.", node_id)
+        self._concurrent_action_limit(action='provisioning')
         event = 'rebuild' if rebuild else 'deploy'
 
         # NOTE(comstud): If the _sync_power_states() periodic task happens
@@ -983,7 +987,8 @@ class ConductorManager(base_manager.BaseConductorManager):
                                    exception.NodeLocked,
                                    exception.InstanceDeployFailure,
                                    exception.InvalidStateRequested,
-                                   exception.NodeProtected)
+                                   exception.NodeProtected,
+                                   exception.ConcurrentActionLimit)
     def do_node_tear_down(self, context, node_id):
         """RPC method to tear down an existing node deployment.
 
@@ -998,8 +1003,11 @@ class ConductorManager(base_manager.BaseConductorManager):
         :raises: InvalidStateRequested when the requested state is not a valid
                  target from the current state.
         :raises: NodeProtected if the node is protected.
+        :raises: ConcurrentActionLimit if this action would exceed the maximum
+                 number of configured concurrent actions of this type.
         """
         LOG.debug("RPC do_node_tear_down called for node %s.", node_id)
+        self._concurrent_action_limit(action='unprovisioning')
 
         with task_manager.acquire(context, node_id, shared=False,
                                   purpose='node tear down') as task:
@@ -1121,7 +1129,8 @@ class ConductorManager(base_manager.BaseConductorManager):
                                    exception.InvalidStateRequested,
                                    exception.NodeInMaintenance,
                                    exception.NodeLocked,
-                                   exception.NoFreeConductorWorker)
+                                   exception.NoFreeConductorWorker,
+                                   exception.ConcurrentActionLimit)
     def do_node_clean(self, context, node_id, clean_steps,
                       disable_ramdisk=False):
         """RPC method to initiate manual cleaning.
@@ -1150,7 +1159,10 @@ class ConductorManager(base_manager.BaseConductorManager):
         :raises: NodeLocked if node is locked by another conductor.
         :raises: NoFreeConductorWorker when there is no free worker to start
                  async task.
+        :raises: ConcurrentActionLimit If this action would exceed the
+                 configured limits of the deployment.
         """
+        self._concurrent_action_limit(action='cleaning')
         with task_manager.acquire(context, node_id, shared=False,
                                   purpose='node manual cleaning') as task:
             node = task.node
@@ -3549,6 +3561,40 @@ class ConductorManager(base_manager.BaseConductorManager):
             # impact DB access if done in excess.
             eventlet.sleep(0)
 
+    def _concurrent_action_limit(self, action):
+        """Check Concurrency limits and block operations if needed.
+
+        This method is used to serve as a central place for the logic
+        for checks on concurrency limits. If a limit is reached, then
+        an appropriate exception is raised.
+
+        :raises: ConcurrentActionLimit If the system configuration
+                 is exceeded.
+        """
+        # NOTE(TheJulia): Keeping this all in one place for simplicity.
+        if action == 'provisioning':
+            node_count = self.dbapi.count_nodes_in_provision_state([
+                states.DEPLOYING,
+                states.DEPLOYWAIT
+            ])
+            if node_count >= CONF.conductor.max_concurrent_deploy:
+                raise exception.ConcurrentActionLimit(
+                    task_type=action)
+
+        if action == 'unprovisioning' or action == 'cleaning':
+            # NOTE(TheJulia): This also checks for the deleting state
+            # which is super transitory, *but* you can get a node into
+            # the state. So in order to guard against a DoS attack, we
+            # need to check even the super transitory node state.
+            node_count = self.dbapi.count_nodes_in_provision_state([
+                states.DELETING,
+                states.CLEANING,
+                states.CLEANWAIT
+            ])
+            if node_count >= CONF.conductor.max_concurrent_clean:
+                raise exception.ConcurrentActionLimit(
+                    task_type=action)
+
 
 @METRICS.timer('get_vendor_passthru_metadata')
 def get_vendor_passthru_metadata(route_dict):
diff --git a/ironic/conf/conductor.py b/ironic/conf/conductor.py
index b1d6bae4f..2161b9434 100644
--- a/ironic/conf/conductor.py
+++ b/ironic/conf/conductor.py
@@ -358,6 +358,32 @@ opts = [
                        'model. The conductor does *not* record this value '
                        'otherwise, and this information is not backfilled '
                        'for prior instances which have been deployed.')),
+    cfg.IntOpt('max_concurrent_deploy',
+               default=250,
+               min=1,
+               mutable=True,
+               help=_('The maximum number of concurrent nodes in deployment '
+                      'which are permitted in this Ironic system. '
+                      'If this limit is reached, new requests will be '
+                      'rejected until the number of deployments in progress '
+                      'is lower than this maximum. As this is a security '
+                      'mechanism requests are not queued, and this setting '
+                      'is a global setting applying to all requests this '
+                      'conductor receives, regardless of access rights. '
+                      'The concurrent deployment limit cannot be disabled.')),
+    cfg.IntOpt('max_concurrent_clean',
+               default=50,
+               min=1,
+               mutable=True,
+               help=_('The maximum number of concurrent nodes in cleaning '
+                      'which are permitted in this Ironic system. '
+                      'If this limit is reached, new requests will be '
+                      'rejected until the number of nodes in cleaning '
+                      'is lower than this maximum. As this is a security '
+                      'mechanism requests are not queued, and this setting '
+                      'is a global setting applying to all requests this '
+                      'conductor receives, regardless of access rights. '
+                      'The concurrent clean limit cannot be disabled.')),
 ]
 
 
diff --git a/ironic/db/api.py b/ironic/db/api.py
index 712919bb3..45e3fe2ca 100644
--- a/ironic/db/api.py
+++ b/ironic/db/api.py
@@ -1416,3 +1416,12 @@ class Connection(object, metaclass=abc.ABCMeta):
         :param entires: A list of node history entriy id's to be
                         queried for deletion.
         """
+
+    @abc.abstractmethod
+    def count_nodes_in_provision_state(self, state):
+        """Count the number of nodes in given provision state.
+
+        :param state: A provision_state value to match for the
+                      count operation. This can be a single provision
+                      state value or a list of values.
+        """
diff --git a/ironic/db/sqlalchemy/api.py b/ironic/db/sqlalchemy/api.py
index 05d5cc45e..c14719af8 100644
--- a/ironic/db/sqlalchemy/api.py
+++ b/ironic/db/sqlalchemy/api.py
@@ -30,6 +30,7 @@ from oslo_utils import timeutils
 from oslo_utils import uuidutils
 from osprofiler import sqlalchemy as osp_sqlalchemy
 import sqlalchemy as sa
+from sqlalchemy import or_
 from sqlalchemy.orm.exc import NoResultFound, MultipleResultsFound
 from sqlalchemy.orm import joinedload
 from sqlalchemy.orm import Load
@@ -2400,3 +2401,26 @@ class Connection(api.Connection):
             ).filter(
                 models.NodeHistory.id.in_(entries)
             ).delete(synchronize_session=False)
+
+    def count_nodes_in_provision_state(self, state):
+        if not isinstance(state, list):
+            state = [state]
+        with _session_for_read() as session:
+            # Intentionally does not use the full ORM model
+            # because that is de-duped by pkey, but we already
+            # have unique constraints on UUID/name, so... shouldn't
+            # be a big deal. #JuliaFamousLastWords.
+            # Anyway, intent here is to be as quick as possible and
+            # literally have the DB do *all* of the world, so no
+            # client side ops occur. The column is also indexed,
+            # which means this will be an index based response.
+            # TODO(TheJulia): This might need to be revised for
+            # SQLAlchemy 2.0 as it should be a scaler select and count
+            # instead.
+            return session.query(
+                models.Node.provision_state
+            ).filter(
+                or_(
+                    models.Node.provision_state == v for v in state
+                )
+            ).count()
diff --git a/ironic/tests/unit/conductor/test_manager.py b/ironic/tests/unit/conductor/test_manager.py
index 378d65f15..5d84dbbef 100644
--- a/ironic/tests/unit/conductor/test_manager.py
+++ b/ironic/tests/unit/conductor/test_manager.py
@@ -1829,6 +1829,7 @@ class ServiceDoNodeDeployTestCase(mgr_utils.ServiceSetUpMixin,
 
     def test_do_node_deploy_maintenance(self, mock_iwdi):
         mock_iwdi.return_value = False
+        self._start_service()
         node = obj_utils.create_test_node(self.context, driver='fake-hardware',
                                           maintenance=True)
         exc = self.assertRaises(messaging.rpc.ExpectedException,
@@ -1843,6 +1844,7 @@ class ServiceDoNodeDeployTestCase(mgr_utils.ServiceSetUpMixin,
         self.assertFalse(mock_iwdi.called)
 
     def _test_do_node_deploy_validate_fail(self, mock_validate, mock_iwdi):
+        self._start_service()
         mock_iwdi.return_value = False
         # InvalidParameterValue should be re-raised as InstanceDeployFailure
         mock_validate.side_effect = exception.InvalidParameterValue('error')
@@ -2389,6 +2391,7 @@ class DoNodeTearDownTestCase(mgr_utils.ServiceSetUpMixin, db_base.DbTestCase):
     @mock.patch('ironic.drivers.modules.fake.FakePower.validate',
                 autospec=True)
     def test_do_node_tear_down_validate_fail(self, mock_validate):
+        self._start_service()
         # InvalidParameterValue should be re-raised as InstanceDeployFailure
         mock_validate.side_effect = exception.InvalidParameterValue('error')
         node = obj_utils.create_test_node(
@@ -8374,7 +8377,6 @@ class NodeHistoryRecordCleanupTestCase(mgr_utils.ServiceSetUpMixin,
         # 9 retained due to days, 3 to config
         self.service._manage_node_history(self.context)
         events = objects.NodeHistory.list(self.context)
-        print(events)
         self.assertEqual(12, len(events))
         events = objects.NodeHistory.list_by_node_id(self.context, 10)
         self.assertEqual(4, len(events))
@@ -8394,3 +8396,73 @@ class NodeHistoryRecordCleanupTestCase(mgr_utils.ServiceSetUpMixin,
         self.assertEqual('one', events[1].event)
         self.assertEqual('two', events[2].event)
         self.assertEqual('three', events[3].event)
+
+
+class ConcurrentActionLimitTestCase(mgr_utils.ServiceSetUpMixin,
+                                    db_base.DbTestCase):
+
+    def setUp(self):
+        super(ConcurrentActionLimitTestCase, self).setUp()
+        self._start_service()
+        self.node1 = obj_utils.get_test_node(
+            self.context,
+            driver='fake-hardware',
+            id=110,
+            uuid=uuidutils.generate_uuid())
+        self.node2 = obj_utils.get_test_node(
+            self.context,
+            driver='fake-hardware',
+            id=111,
+            uuid=uuidutils.generate_uuid())
+        self.node3 = obj_utils.get_test_node(
+            self.context,
+            driver='fake-hardware',
+            id=112,
+            uuid=uuidutils.generate_uuid())
+        self.node4 = obj_utils.get_test_node(
+            self.context,
+            driver='fake-hardware',
+            id=113,
+            uuid=uuidutils.generate_uuid())
+        # Create the nodes, as the tasks need to operate across tables.
+        self.node1.create()
+        self.node2.create()
+        self.node3.create()
+        self.node4.create()
+
+    def test_concurrent_action_limit_deploy(self):
+        self.node1.provision_state = states.DEPLOYING
+        self.node2.provision_state = states.DEPLOYWAIT
+        self.node1.save()
+        self.node2.save()
+        CONF.set_override('max_concurrent_deploy', 2, group='conductor')
+        self.assertRaises(
+            exception.ConcurrentActionLimit,
+            self.service._concurrent_action_limit,
+            'provisioning')
+        self.service._concurrent_action_limit('unprovisioning')
+        self.service._concurrent_action_limit('cleaning')
+        CONF.set_override('max_concurrent_deploy', 3, group='conductor')
+        self.service._concurrent_action_limit('provisioning')
+
+    def test_concurrent_action_limit_cleaning(self):
+        self.node1.provision_state = states.DELETING
+        self.node2.provision_state = states.CLEANING
+        self.node3.provision_state = states.CLEANWAIT
+        self.node1.save()
+        self.node2.save()
+        self.node3.save()
+
+        CONF.set_override('max_concurrent_clean', 3, group='conductor')
+        self.assertRaises(
+            exception.ConcurrentActionLimit,
+            self.service._concurrent_action_limit,
+            'cleaning')
+        self.assertRaises(
+            exception.ConcurrentActionLimit,
+            self.service._concurrent_action_limit,
+            'unprovisioning')
+        self.service._concurrent_action_limit('provisioning')
+        CONF.set_override('max_concurrent_clean', 4, group='conductor')
+        self.service._concurrent_action_limit('cleaning')
+        self.service._concurrent_action_limit('unprovisioning')
diff --git a/ironic/tests/unit/db/test_nodes.py b/ironic/tests/unit/db/test_nodes.py
index eb5200f4e..b4d70b2dd 100644
--- a/ironic/tests/unit/db/test_nodes.py
+++ b/ironic/tests/unit/db/test_nodes.py
@@ -1081,3 +1081,39 @@ class DbNodeTestCase(base.DbTestCase):
                                 self.dbapi.check_node_list,
                                 [node1.uuid, 'this/cannot/be/a/name'])
         self.assertIn('this/cannot/be/a/name', str(exc))
+
+    def test_node_provision_state_count(self):
+        active_nodes = 5
+        manageable_nodes = 3
+        deploywait_nodes = 1
+        for i in range(0, active_nodes):
+            utils.create_test_node(uuid=uuidutils.generate_uuid(),
+                                   provision_state=states.ACTIVE)
+        for i in range(0, manageable_nodes):
+            utils.create_test_node(uuid=uuidutils.generate_uuid(),
+                                   provision_state=states.MANAGEABLE)
+        for i in range(0, deploywait_nodes):
+            utils.create_test_node(uuid=uuidutils.generate_uuid(),
+                                   provision_state=states.DEPLOYWAIT)
+
+        self.assertEqual(
+            active_nodes,
+            self.dbapi.count_nodes_in_provision_state(states.ACTIVE)
+        )
+        self.assertEqual(
+            manageable_nodes,
+            self.dbapi.count_nodes_in_provision_state(states.MANAGEABLE)
+        )
+        self.assertEqual(
+            deploywait_nodes,
+            self.dbapi.count_nodes_in_provision_state(states.DEPLOYWAIT)
+        )
+        total = active_nodes + manageable_nodes + deploywait_nodes
+        self.assertEqual(
+            total,
+            self.dbapi.count_nodes_in_provision_state([
+                states.ACTIVE,
+                states.MANAGEABLE,
+                states.DEPLOYWAIT
+            ])
+        )
diff --git a/releasenotes/notes/concurrency-limit-control-4b101bca7136e08d.yaml b/releasenotes/notes/concurrency-limit-control-4b101bca7136e08d.yaml
new file mode 100644
index 000000000..5eb8dd449
--- /dev/null
+++ b/releasenotes/notes/concurrency-limit-control-4b101bca7136e08d.yaml
@@ -0,0 +1,23 @@
+---
+features:
+  - |
+    Adds a concurrency limiter for number of nodes in states related to
+    *Cleaning* and *Provisioning* operations across the ironic deployment.
+    These settings default to a maximum number of concurrent deployments to
+    ``250`` and a maximum number of concurrent deletes and cleaning operations
+    to ``50``. These settings can be tuned using
+    ``[conductor]max_concurrent_deploy`` and
+    ``[conductor]max_concurrent_clean``, respectively.
+    The defaults should generally be good for most operators in most cases.
+    Large scale operators should evaluate the defaults and tune appropriately
+    as this feature cannot be disabled, as it is a security mechanism.
+upgrade:
+  - |
+    Large scale operators should be aware that a new feature, referred to as
+    "Concurrent Action Limit" was introduced as a security mechanism to
+    provide a means to limit attackers, or faulty scripts, from potentially
+    causing irreperable harm to an environment. This feature cannot be
+    disabled, and operators are encouraged to tune the new settings
+    ``[conductor]max_concurrent_deploy`` and
+    ``[conductor]max_concurrent_clean`` to match the needs of their
+    environment.