Use a single keypair for multiple instances

When I ran manila scenario tests, some tests failed due to
ssh key authentication. I noticed that tests with single
instance pass, however, tests with more than one instance
(e.g. "test_read_write_two_vms" test) fail.
I figured out that every instance initialization creates a
unique keypair.
An unnecessary resource duplication, when a single user boots
more than one instance. Depending on test flow this may also
cause keypair mismatch.

Change-Id: Ic685d1b9574daf7e6c9b90d5636f1b614a70b0da
Related-bug: #1858024

manila_tempest_tests/tests/scenario/manager_share.py

@@ -132,7 +132,10 @@ class ShareScenarioTest(manager.NetworkScenarioTest):
         return share_network
 
     def boot_instance(self, wait_until="ACTIVE"):
-        self.keypair = self.create_keypair()
+        # In case of multiple instances, use a single keypair to prevent a keys
+        # mismatch.
+        if not hasattr(self, 'keypair'):
+            self.keypair = self.create_keypair()
         security_groups = [{'name': self.security_group['name']}]
         create_kwargs = {
             'key_name': self.keypair['name'],

releasenotes/notes/bug-1858024-fa76d4c5b27f099b.yaml

@@ -0,0 +1,8 @@
+---
+fixes:
+  - |
+    Fixed bug #1858024. Define a signle key for multiple instances.
+    Currently every instance initialization creates a unique keypair.
+    An unnecessary resource duplication, when a single user boots more
+    than one instance.
+    Depending on test flow this may also cause keypair mismatch.