openstack
/
nova
Code Issues Proposed changes

Update docs for live_migration_progress_timeout option 

Change I1a1143ddf8da5fb9706cf53dbfd6cbe84e606ae1 in Ocata
deprecated the libvirt.live_migration_progress_timeout
and disabled it by default. This change updates the config
option help to refer to the bug so people don't have to hunt
for it via git history, and also touches up the admin docs.
In the one doc, mention of the option is removed altogether
because it basically says, "here is a loaded gun, but don't
use it!". It's better to just not mention the option at all.

Change-Id: I33f3d508a2af6c94435f86ac740cf24b97dba76e
Related-Bug: #1644248
This commit is contained in:
Matt Riedemann 2018-09-07 16:54:41 -04:00
parent 3d31e6c95a
commit f34877f936
3 changed files with 9 additions and 15 deletions
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12
doc/source/admin/configuring-migrations.rst
View File

@ -231,18 +231,6 @@ memory-intensive instances succeed.
example, shared-storage live migration of an instance with 8GiB memory will
time out after 6400 seconds.
#. **Live migration progress timeout**
The Compute service also aborts a live migration when it detects that memory
copy is not making progress for a certain time. You can set this time, in
seconds, through the configurable parameter
``live_migration_progress_timeout``.
In Ocata, the default value of ``live_migration_progress_timeout`` is 0,
which disables progress timeouts. You should not change this value, since
the algorithm that detects memory copy progress has been determined to be
unreliable. It may be re-enabled in future releases.
#. **Instance downtime**
Near the end of the memory copy, the instance is paused for a short time so

7
doc/source/admin/live-migration-usage.rst
View File

@ -239,8 +239,9 @@ out:
live migration not completed after 1800 sec
The Compute service also cancels migrations when the memory copy seems to make
no progress. Ocata disables this feature by default, but it can be enabled
using the configuration parameter ``live_migration_progress_timeout``. Should
no progress. This feature is `disabled by default`_, but it can be enabled
using the configuration parameter
:oslo.config:option:`libvirt.live_migration_progress_timeout`. Should
this be the case, you may find the following message in the log:
.. code-block:: console
@ -248,6 +249,8 @@ this be the case, you may find the following message in the log:
WARNING nova.virt.libvirt.migration [req-...] [instance: ...]
live migration stuck for 150 sec
.. _disabled by default: https://review.openstack.org/#/c/431635/
Addressing migration timeouts
-----------------------------

5
nova/conf/libvirt.py
View File

@ -397,7 +397,10 @@ Related options:
cfg.IntOpt('live_migration_progress_timeout',
default=0,
deprecated_for_removal=True,
deprecated_reason="Serious bugs found in this feature.",
deprecated_reason="""
Serious bugs found in this feature, see
https://bugs.launchpad.net/nova/+bug/1644248 for details.
""",
mutable=True,
help="""
Time to wait, in seconds, for migration to make forward progress in