libvirtd restart can sometimes cause multiple nova-compute connections
Bug #1240905 reported by
Tom Hancock
This bug affects 2 people
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
OpenStack Compute (nova) |
Fix Released
|
Medium
|
Unassigned | ||
Havana |
Fix Released
|
Undecided
|
Unassigned |
Bug Description
libvirt driver's get_connection() is not thread safe in the
presence of a libvirtd restart during concurrent incoming
requests.
With existing code, each request will in turn call get_connection,
find the connection is broken, try to create new one, block
for a while and yield to the next thread to do the same.
You get as many connections as there are incoming requests
and only the last one is used finally. If enough are incoming
these connections can exhaust the client pool configured
for libvirtd.
One fix is to hold a lock while creating the connection.
Note that has_min_version calls _conn which calls get_connection
so the lock may not be held over the call to has_min_version()
Changed in nova: | |
importance: | Undecided → Medium |
tags: | added: havana-backport-potential |
Changed in nova: | |
milestone: | none → icehouse-1 |
Changed in nova: | |
status: | Fix Committed → Fix Released |
Changed in nova: | |
milestone: | icehouse-1 → 2014.1 |
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Reviewed: https:/ /review. openstack. org/52401 github. com/openstack/ nova/commit/ b2e64e379835f57 128e66f50743813 0eda716814
Committed: http://
Submitter: Jenkins
Branch: master
commit b2e64e379835f57 128e66f50743813 0eda716814
Author: Tom Hancock <email address hidden>
Date: Thu Oct 17 09:48:54 2013 +0000
make libvirt driver get_connection thread-safe
libvirt driver's get_connection is not thread safe in the
presence of a libvirtd restart during concurrent incoming
requests.
With existing code each will in turn call get_connection,
find the connection is broken, try to create new one, block
for a while and yield to the next thread to do the same.
You get as many connections as there are incoming requests
and only the last one is used finally. If enough are incoming
these connections can exhaust the client pool configured
for libvirtd.
One fix is to hold a lock while creating the connection.
Note that has_min_version calls _conn which calls get_connection
and thus the direct call to _has_min_version()
Also added the exception text if it fails to register an event
handler for lifecycle events.
Change-Id: I090765802bfe44 3440f16722bc7c4 3b6280fe56a
Fixes: bug #1240905