Wait for guest after resize

To stabilize test_resize_server_with_multiattached_volume we need to
wait for the guest OS to fully boot after the resize and before the test
attempts to detach the volume.

Closes-Bug #1960346

Change-Id: I85ee21868c9281d081c491ee590fe1457f5aa997

tempest/api/compute/base.py

@@ -456,15 +456,31 @@ class BaseV2ComputeTest(api_version_utils.BaseMicroversionTest,
         except Exception:
             LOG.exception('Failed to delete server %s', server_id)
 
-    def resize_server(self, server_id, new_flavor_id, **kwargs):
+    def resize_server(
+        self, server_id, new_flavor_id, wait_until='ACTIVE', **kwargs
+    ):
         """resize and confirm_resize an server, waits for it to be ACTIVE."""
         self.servers_client.resize_server(server_id, new_flavor_id, **kwargs)
         waiters.wait_for_server_status(self.servers_client, server_id,
                                        'VERIFY_RESIZE')
         self.servers_client.confirm_resize_server(server_id)
+
         waiters.wait_for_server_status(
             self.servers_client, server_id, 'ACTIVE')
         server = self.servers_client.show_server(server_id)['server']
+
+        validation_resources = self.get_class_validation_resources(
+            self.os_primary)
+        if (
+            validation_resources and
+            wait_until in ("SSHABLE", "PINGABLE") and
+            CONF.validation.run_validation
+        ):
+            tenant_network = self.get_tenant_network()
+            compute.wait_for_ssh_or_ping(
+                server, self.os_primary, tenant_network,
+                True, validation_resources, wait_until, True)
+
         self.assert_flavor_equal(new_flavor_id, server['flavor'])
 
     def reboot_server(self, server_id, type):

tempest/api/compute/volumes/test_attach_volume.py

@@ -378,10 +378,19 @@ class AttachVolumeMultiAttachTest(BaseAttachVolumeTest):
                   the created volume, and dict of server ID to volumeAttachment
                   dict entries
         """
+        validation_resources = self.get_class_validation_resources(
+            self.os_primary)
+
         servers = []
         for x in range(2):
             name = 'multiattach-server-%i' % x
-            servers.append(self.create_test_server(name=name))
+            servers.append(
+                self.create_test_server(
+                    name=name,
+                    validatable=True,
+                    validation_resources=validation_resources
+                )
+            )
 
         # Now wait for the servers to be ACTIVE.
         for server in servers:
@@ -492,7 +501,10 @@ class AttachVolumeMultiAttachTest(BaseAttachVolumeTest):
         servers, volume, _ = self._create_and_multiattach()
 
         for server in servers:
-            self.resize_server(server['id'], self.flavor_ref_alt)
+            # We need to wait until the guest OS fully boots up as we are going
+            # to detach volumes after the resize. See bug #1960346.
+            self.resize_server(
+                server['id'], self.flavor_ref_alt, wait_until='SSHABLE')
 
         for server in servers:
             self._detach_multiattach_volume(volume['id'], server['id'])