metastatic: Pass tenant_name to backing node request

Currently, we don't store the tenant_name on the backing node of a
metastatic node, which leads to wrong metrics (per-tenant resource
usage metrics) and tenant quota calculation (maybe other places
affected, too).
To fix this, pass the tenant_name from the original metastatic request
from zuul down to the node request issued by the metastatic driver so
this info eventually lands on the backing node.

One thing to note is that when a backing node is reused, the tenant_name
attribute will not be updated. This is the same behaviour we also have
with other backing node metadata (e.g. instance tags).

Change-Id: Iaaca8c291be50273369f0255690f78851bef26d4

nodepool/driver/metastatic/adapter.py

@@ -139,7 +139,10 @@ class MetastaticInstance(statemachine.Instance):
         self.slot = slot
 
     def getQuotaInformation(self):
-        return QuotaInformation(instances=1)
+        # metastatic nodes shall not be counted into used quota because the
+        # backing node will do so. To not count used instances twice, return
+        # QuotaInformation with 0 instances here.
+        return QuotaInformation(instances=0)
 
 
 class MetastaticDeleteStateMachine(statemachine.StateMachine):
@@ -166,7 +169,7 @@ class MetastaticCreateStateMachine(statemachine.StateMachine):
     COMPLETE = 'complete'
 
     def __init__(self, adapter, hostname, label, image_external_id,
-                 metadata):
+                 metadata, request):
         super().__init__()
         self.adapter = adapter
         self.attempts = 0
@@ -174,13 +177,14 @@ class MetastaticCreateStateMachine(statemachine.StateMachine):
         self.metadata = metadata
         self.hostname = hostname
         self.label = label
+        self.request = request
         self.node_id = metadata['nodepool_node_id']
 
     def advance(self):
         if self.state == self.START:
             self.backing_node_record, self.slot = \
                 self.adapter._allocateBackingNode(
-                    self.label, self.node_id)
+                    self.label, self.node_id, self.request)
             if self.backing_node_record.node_id is None:
                 # We need to make a new request
                 self.state = self.REQUESTING
@@ -280,7 +284,8 @@ class MetastaticAdapter(statemachine.Adapter):
                               image_external_id, metadata,
                               request, az, log):
         return MetastaticCreateStateMachine(self, hostname, label,
-                                            image_external_id, metadata)
+                                            image_external_id, metadata,
+                                            request)
 
     def getDeleteStateMachine(self, external_id, log):
         return MetastaticDeleteStateMachine(self, external_id)
@@ -431,7 +436,7 @@ class MetastaticAdapter(statemachine.Adapter):
     def _setProvider(self, provider):
         self._provider = provider
 
-    def _allocateBackingNode(self, label, node_id):
+    def _allocateBackingNode(self, label, node_id, request):
         self._init()
         # if we have room for the label, allocate and return existing slot
         # otherwise, make a new backing node
@@ -449,6 +454,7 @@ class MetastaticAdapter(statemachine.Adapter):
                 req.node_types = [label.backing_label]
                 req.state = zk.REQUESTED
                 req.requestor = self.my_id
+                req.tenant_name = request.tenant_name
                 self.zk.storeNodeRequest(req, priority='100')
                 backing_node_record = BackingNodeRecord(
                     label.name, label.max_parallel_jobs)

nodepool/tests/unit/test_driver_metastatic.py

@@ -123,6 +123,7 @@ class TestDriverMetastatic(tests.DBTestCase):
             'metaattr': 'meta',
             'testattr': 'metastatic',
         })
+        self.assertEqual(bn1.tenant_name, 'tenant-1')
 
         # Allocate a second node, should have same backing node
         node2 = self._requestNode()