Merge "filter: add per-aggregate filter to configure max_io_ops_per_host"

nova/scheduler/filters/io_ops_filter.py

@@ -15,8 +15,10 @@
 
 from oslo.config import cfg
 
+from nova.i18n import _LW
 from nova.openstack.common import log as logging
 from nova.scheduler import filters
+from nova.scheduler.filters import utils
 
 LOG = logging.getLogger(__name__)
 
@@ -34,12 +36,16 @@ CONF.register_opt(max_io_ops_per_host_opt)
 class IoOpsFilter(filters.BaseHostFilter):
     """Filter out hosts with too many concurrent I/O operations."""
 
+    def _get_max_io_ops_per_host(self, host_state, filter_properties):
+        return CONF.max_io_ops_per_host
+
     def host_passes(self, host_state, filter_properties):
         """Use information about current vm and task states collected from
         compute node statistics to decide whether to filter.
         """
         num_io_ops = host_state.num_io_ops
-        max_io_ops = CONF.max_io_ops_per_host
+        max_io_ops = self._get_max_io_ops_per_host(
+            host_state, filter_properties)
         passes = num_io_ops < max_io_ops
         if not passes:
             LOG.debug("%(host_state)s fails I/O ops check: Max IOs per host "
@@ -47,3 +53,27 @@ class IoOpsFilter(filters.BaseHostFilter):
                         {'host_state': host_state,
                          'max_io_ops': max_io_ops})
         return passes
+
+
+class AggregateIoOpsFilter(IoOpsFilter):
+    """AggregateIoOpsFilter with per-aggregate the max io operations.
+
+    Fall back to global max_io_ops_per_host if no per-aggregate setting found.
+    """
+
+    def _get_max_io_ops_per_host(self, host_state, filter_properties):
+        # TODO(uni): DB query in filter is a performance hit, especially for
+        # system with lots of hosts. Will need a general solution here to fix
+        # all filters with aggregate DB call things.
+        aggregate_vals = utils.aggregate_values_from_db(
+            filter_properties['context'],
+            host_state.host,
+            'max_io_ops_per_host')
+        try:
+            value = utils.validate_num_values(
+                aggregate_vals, CONF.max_io_ops_per_host, cast_to=int)
+        except ValueError as e:
+            LOG.warn(_LW("Could not decode max_io_ops_per_host: '%s'"), e)
+            value = CONF.max_io_ops_per_host
+
+        return value