diff options
| author | Peter Feiner <peter@gridcentric.ca> | 2013-06-19 21:14:43 +0000 |
|---|---|---|
| committer | Peter Feiner <peter@gridcentric.ca> | 2013-06-26 14:28:46 +0000 |
| commit | 0ed62fb7affbda4a701c2175e95aa6f92038604c (patch) | |
| tree | b8bef608c50c5b0e6c134902cd41ef02bac46c74 /nova/db | |
| parent | 7696c3c11f0de855cbc53cc04ee7d2be07ae3b9c (diff) | |
db.compute_node_update: ignore values['update_at']
When individual instances are updated (e.g., during spawn and
terminate), ResourceTracker (in nova.compute.resource_tracker) calls
compute_node_update with values=self.compute_node. Since
self.compute_node is an instance of ComputeNode that was retrieved
from the database, it has updated_at set. Since updated_at is in
values, sqlalchemy doesn't automatically change the record's
updated_at column (see
nova.openstack.common.db.sqlalchemy.models.TimestampMixin). Moreover,
since updated_at is set to the last value's updated_at, updated_at
effectively doesn't change until values without updated_at are sent,
which only happens during the periodic task that calls
ResourceTracker.update_available_resources.
Nova-scheduler relies on ComputeNode.updated_at to keep its model of
available resources up-to-date. In particular, nova-scheduler doesn't
play a role in instance termination, so it doesn't account for freed
resources until ComputeNode.updated_at changes. Thus, between
nova-compute's periodic calls to
ResourceTracker.update_available_resources, nova-scheduler's model of
available resources monotonically decreases. If, for example, a node
has resources for 10 instances, and you manage to boot 10, terminate
10, then attempt to boot another before the end of the period,
nova-scheduler won't schedule the new instance on the vacant node.
Fixes bug #1194900.
Note that f398b9e195cda582bad57396b097dec274384c07 fixed a separate
issue (bug #1153778) related to ComputeNode.update_at being stale.
Change-Id: Ifd1e56edfd811241816970715071876857de80d3
Diffstat (limited to 'nova/db')
| -rw-r--r-- | nova/db/sqlalchemy/api.py | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/nova/db/sqlalchemy/api.py b/nova/db/sqlalchemy/api.py index fd79ae215..12d1a582f 100644 --- a/nova/db/sqlalchemy/api.py +++ b/nova/db/sqlalchemy/api.py @@ -555,8 +555,7 @@ def compute_node_update(context, compute_id, values, prune_stats=False): # Always update this, even if there's going to be no other # changes in data. This ensures that we invalidate the # scheduler cache of compute node data in case of races. - if 'updated_at' not in values: - values['updated_at'] = timeutils.utcnow() + values['updated_at'] = timeutils.utcnow() convert_datetimes(values, 'created_at', 'deleted_at', 'updated_at') compute_ref.update(values) return compute_ref |