openstack/nova
Code Issues Proposed changes

Add logging when filtering returns nothing.

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When hosts are filtered for a request, and no host passes all the
filters, operators can only see the last filter run; they have no
visibility into which filter removed which host. This attempts to
improve this situation by tracking the hosts remaining after each
filter is run and the number of hosts removed. If no host is left, to
log that information along with the reservation ID and instance UUID
of the request. Since that can be a lot of information, it will call
LOG.info with just the counts for all but the final filter, which
will contain the last deleted host names; LOG.debug will output the
full record of each filter and the hosts remaining after each step.
This will better enable operators to determine why a particular host
was not selected.

Change-Id: I6173274a03bd8712eb4d63c7a998bb02abdecf4b
Blueprint: no-valid-host-reporting
This commit is contained in:
EdLeafe
2015-06-15 16:07:54 -05:00
parent 70946d48cc
commit 0f67836de2
2 changed files with 116 additions and 1 deletions
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41
nova/filters.py
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@@ -68,18 +68,57 @@ class BaseFilterHandler(loadables.BaseLoader):
def get_filtered_objects(self, filters, objs, filter_properties, index=0):
list_objs = list(objs)
LOG.debug("Starting with %d host(s)", len(list_objs))
# Track the hosts as they are removed. The 'full_filter_results' list
# contains the host/nodename info for every host that passes each
# filter, while the 'part_filter_results' list just tracks the number
# removed by each filter, unless the filter returns zero hosts, in
# which case it records the host/nodename for the last batch that was
# removed. Since the full_filter_results can be very large, it is only
# recorded if the LOG level is set to debug.
part_filter_results = []
full_filter_results = []
log_msg = "%(cls_name)s: (start: %(start)s, end: %(end)s)"
for filter_ in filters:
if filter_.run_filter_for_index(index):
cls_name = filter_.__class__.__name__
start_count = len(list_objs)
objs = filter_.filter_all(list_objs, filter_properties)
if objs is None:
LOG.debug("Filter %s says to stop filtering", cls_name)
return
list_objs = list(objs)
if not list_objs:
end_count = len(list_objs)
part_filter_results.append(log_msg % {"cls_name": cls_name,
"start": start_count, "end": end_count})
if list_objs:
remaining = [(getattr(obj, "host", obj),
getattr(obj, "nodename", ""))
for obj in list_objs]
full_filter_results.append((cls_name, remaining))
else:
LOG.info(_LI("Filter %s returned 0 hosts"), cls_name)
full_filter_results.append((cls_name, None))
break
LOG.debug("Filter %(cls_name)s returned "
"%(obj_len)d host(s)",
{'cls_name': cls_name, 'obj_len': len(list_objs)})
if not list_objs:
# Log the filtration history
rspec = filter_properties.get("request_spec", {})
inst_props = rspec.get("instance_properties", {})
msg_dict = {"res_id": inst_props.get("reservation_id", ""),
"inst_uuid": inst_props.get("uuid", ""),
"str_results": str(full_filter_results),
}
full_msg = ("Filtering removed all hosts for the request with "
"reservation ID '%(res_id)s' and instance ID "
"'%(inst_uuid)s'. Filter results: %(str_results)s"
) % msg_dict
msg_dict["str_results"] = str(part_filter_results)
part_msg = _LI("Filtering removed all hosts for the request with "
"reservation ID '%(res_id)s' and instance ID "
"'%(inst_uuid)s'. Filter results: %(str_results)s"
) % msg_dict
LOG.debug(full_msg)
LOG.info(part_msg)
return list_objs