Put ensure_share into thread pool to speed up the startup of share service

when we need to start or restart manila share service, will call
init_host().
and call ensure_driver_resources() in init_host(),
will call self.driver.ensure_shares or self.driver.ensure_share to
update all share instances in that host. Currently, only NetApp and LVM
implement self.driver.ensure_shares, Other manufacturers are using
self.driver.ensure_share.
   in large-scale environment, there are lot of share instances in one
host. this will lead to take much time to ensure_share.
   so we can put this operation into the thread pool to speed up the
startup of the service.

Closes-Bug: #1909847
Change-Id: I295d0de0958ebfedd89441f1a2c1b447b74693a0

manila/manager.py

@@ -51,6 +51,8 @@ This module provides Manager, a base class for managers.
 
 """
 
+
+from eventlet import greenpool
 from oslo_config import cfg
 from oslo_log import log
 from oslo_service import periodic_task
@@ -139,8 +141,12 @@ class SchedulerDependentManager(Manager):
         self.last_capabilities = None
         self.service_name = service_name
         self.scheduler_rpcapi = scheduler_rpcapi.SchedulerAPI()
+        self._tp = greenpool.GreenPool()
         super(SchedulerDependentManager, self).__init__(host, db_driver)
 
+    def _add_to_threadpool(self, func, *args, **kwargs):
+        self._tp.spawn_n(func, *args, **kwargs)
+
     def update_service_capabilities(self, capabilities):
         """Remember these capabilities to send on next periodic update."""
         self.last_capabilities = capabilities

manila/share/manager.py

@@ -131,6 +131,10 @@ share_manager_opts = [
                      'configured, this option must be set to False. '
                      'If set to False - gathering share usage size will be'
                      ' disabled.'),
+    cfg.BoolOpt('share_service_inithost_offload',
+                default=False,
+                help='Offload pending share ensure during '
+                     'share service startup'),
 ]
 
 CONF = cfg.CONF
@@ -447,7 +451,12 @@ class ShareManager(manager.SchedulerDependentManager):
                     LOG.exception("Caught exception trying ensure "
                                   "share instances.")
                 else:
-                    self._ensure_share(ctxt, update_share_instances)
+                    for share_instance in update_share_instances:
+                        if CONF.share_service_inithost_offload:
+                            self._add_to_threadpool(self._ensure_share,
+                                                    ctxt, share_instance)
+                        else:
+                            self._ensure_share(ctxt, share_instance)
 
         if new_backend_info:
             self.db.backend_info_update(
@@ -517,20 +526,19 @@ class ShareManager(manager.SchedulerDependentManager):
                             "access rules for snapshot instance %s.",
                             snap_instance['id'])
 
-    def _ensure_share(self, ctxt, share_instances):
-        for share_instance in share_instances:
-            try:
-                export_locations = self.driver.ensure_share(
-                    ctxt, share_instance,
-                    share_server=share_instance['share_server'])
-            except Exception:
-                LOG.exception("Caught exception trying ensure "
-                              "share '%(s_id)s'.",
-                              {'s_id': share_instance['id']})
-                continue
-            if export_locations:
-                self.db.share_export_locations_update(
-                    ctxt, share_instance['id'], export_locations)
+    def _ensure_share(self, ctxt, share_instance):
+        export_locations = None
+        try:
+            export_locations = self.driver.ensure_share(
+                ctxt, share_instance,
+                share_server=share_instance['share_server'])
+        except Exception:
+            LOG.exception("Caught exception trying ensure "
+                          "share '%(s_id)s'.",
+                          {'s_id': share_instance['id']})
+        if export_locations:
+            self.db.share_export_locations_update(
+                ctxt, share_instance['id'], export_locations)
 
     def _check_share_server_backend_limits(
             self, context, available_share_servers, share_instance=None):

releasenotes/notes/bug-1909847-put-ensure-share-into_thread-pool-e658f21c7caad668.yaml

@@ -0,0 +1,16 @@
+---
+upgrade:
+  - |
+    This fix introduces a new configuration item, which named
+    "share_service_inithost_offload", default value is False, if set it True,
+    will put ensure_share operation into thread pool to speed up startup of
+    manila share service.
+fixes:
+  - |
+    The manila share servie now can put ensure_share operation into thread
+    pool during service startup process. See `Launchpad bug#1890833
+    <https://launchpad.net/bugs/1909847>`_ for more details.
+  - |
+    The manila share service now honors the configuration option
+    "share_service_inithost_offload", and it can be used to reduce the time
+    required for the manila share aervice to start up.