'disabled' field to use in host plugin and admins can create lease wh…

…en host is non reservable

When disabled key is present in extra capabilities handle it by setting it or unsetting it based on the value for the key

When disabled field is set to True for a host, the host also changes its reservable status to False.

Disabled key can only be set by an admin

An admin can create a lease on a host that is non reservable

blazar/plugins/oshosts/host_plugin.py

@@ -343,6 +343,9 @@ def create_computehost(self, host_values):
             # Do not use nova's primary key for this host.
             # Instead, generate a new one.
             del host_details['id']
+        if 'disabled' in host_values:
+            self.handle_disabled_key(host_id, host_values['disabled'])
+            del host_values['disabled']
         # NOTE(sbauza): Only last duplicate name for same extra capability
         # will be stored
         to_store = set(host_values.keys()) - set(host_details.keys())
@@ -420,7 +423,9 @@ def update_computehost(self, host_id, values):
         # nothing to update
         if not values:
             return self.get_computehost(host_id)
-
+        if 'disabled' in values:
+            self.handle_disabled_key(host_id, values['disabled'])
+            del values['disabled']
         cant_update_extra_capability = []
         cant_delete_extra_capability = []
         previous_capabilities = self._get_extra_capabilities(host_id)
@@ -515,6 +520,24 @@ def delete_computehost(self, host_id):
             # they have to rerun
             raise manager_ex.CantDeleteHost(host=host_id, msg=str(e))
 
+    def handle_disabled_key(self, host_id, value):
+        # only admin can set/unset 'disabled' flag
+        if self._is_admin():
+            host_details = self.get_computehost(host_id)
+            new_disabled_flag = False if value is None else True
+            self.set_disabled(host_details, new_disabled_flag)
+
+    def set_disabled(self, resource, is_disabled):
+        host_update_values = {"disabled": is_disabled}
+        # if a host is set as disabled, then it should not be reservable
+        if is_disabled:
+            host_update_values['reservable'] = False
+        db_api.host_update(resource["id"], host_update_values)
+        LOG.warn(
+            '%s %s.', resource["hypervisor_hostname"],
+            "is set disabled" if is_disabled else "is not disabled"
+        )
+
     def list_allocations(self, query, detail=False):
         hosts_id_list = [h['id'] for h in db_api.host_list()]
         options = self.get_query_options(query, QUERY_TYPE_ALLOCATION)
@@ -635,6 +658,11 @@ def allocation_candidates(self, values):
 
         return host_ids
 
+    def _is_admin(self):
+        ctx = context.current()
+        ctx_dict = ctx.dict()
+        return ctx_dict.get('is_admin', False)
+
     def _matching_hosts(self, hypervisor_properties, resource_properties,
                         count_range, start_date, end_date, project_id):
         """Return the matching hosts (preferably not allocated)
@@ -658,7 +686,12 @@ def _matching_hosts(self, hypervisor_properties, resource_properties,
         if resource_properties:
             filter_array += plugins_utils.convert_requirements(
                 resource_properties)
-        for host in db_api.reservable_host_get_all_by_queries(filter_array):
+        # admin can create a lease for host with 'reservable' False
+        if self._is_admin():
+            hosts = db_api.host_get_all_by_queries(filter_array)
+        else:
+            hosts = db_api.reservable_host_get_all_by_queries(filter_array)
+        for host in hosts:
             if not self.is_project_allowed(project_id, resource_properties):
                 continue
             if not db_api.host_allocation_get_all_by_values(
@@ -905,6 +938,9 @@ def notification_callback(self, event_type, payload):
         return reservation_flags
 
     def set_reservable(self, resource, is_reservable):
+        if resource['disabled']:
+            LOG.warn(f"{resource['hypervisor_hostname']} is disabled - cannot set reservable")
+            return
         db_api.host_update(resource["id"], {"reservable": is_reservable})
         LOG.warn('%s %s.', resource["hypervisor_hostname"],
                  "recovered" if is_reservable else "failed")