openstack/nova
Code Issues Proposed changes

Update live_migration_downtime definition

Browse Source 
Before, the definition of live_migration_downtime didn't explain
if any exception/timeout occurs if the migration exceeds the value.
This is just used as a reference for nova and if any problem happens
when the VM gets paused, there will be no abort or force-complete.

Closes-Bug: #1960345
Signed-off-by: Pedro Almeida <pedro.monteiroazevedodemouraalmeida@windriver.com>
Change-Id: I336481d1801a367b5628fedcd2aa5f5cf763355a
This commit is contained in:
Pedro Almeida
2022-02-08 14:51:46 -03:00
parent b6fe7521af
commit de110b042d
2 changed files with 8 additions and 5 deletions
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6
doc/source/admin/configuring-migrations.rst
View File

@@ -263,8 +263,10 @@ memory-intensive instances succeed.
live_migration_downtime_steps = 10
live_migration_downtime_delay = 75
``live_migration_downtime`` sets the maximum permitted downtime for a live
migration, in *milliseconds*. The default is 500.
``live_migration_downtime`` sets the target maximum period of time Nova will
try to keep the instance paused during the last part of the memory copy, in
*milliseconds*. This value may be exceeded if there is any reduction on the
transfer rate after the VM is paused. The default is 500.
``live_migration_downtime_steps`` sets the total number of adjustment steps
until ``live_migration_downtime`` is reached. The default is 10 steps.

7
nova/conf/libvirt.py
View File

@@ -321,13 +321,14 @@ Please refer to the libvirt documentation for further details.
default=500,
min=100,
help="""
Maximum permitted downtime, in milliseconds, for live migration
switchover.
Target maximum period of time Nova will try to keep the instance paused
during the last part of the memory copy, in *milliseconds*.
Will be rounded up to a minimum of 100ms. You can increase this value
if you want to allow live-migrations to complete faster, or avoid
live-migration timeout errors by allowing the guest to be paused for
longer during the live-migration switch over.
longer during the live-migration switch over. This value may be exceeded
if there is any reduction on the transfer rate after the VM is paused.
Related options: