migration fails if instance build failed on destination host
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
OpenStack Compute (nova) |
Fix Released
|
Medium
|
Matt Riedemann | ||
Ocata |
Fix Committed
|
Medium
|
Matt Riedemann | ||
Pike |
Fix Committed
|
Medium
|
Matt Riedemann | ||
Queens |
Fix Committed
|
Medium
|
Matt Riedemann |
Bug Description
(OpenStack Nova, commit d8b30c3772, per OSA-14.2.7)
if an instance build fails on a hypervisor the "retry" field of the instance's request spec is populated with which host and how many times it attempted to retry the build. this field remains populated during the life-time of the instance.
if a live-migration for the same instance is requested, the conductor loads this request spec and passes it on to the scheduler. the scheduler will fail the migration request on RetryFilter since the target was already known to have failed (albeit, for the build).
with the help of mriedem and melwitt of #openstack-nova, we determined that migration retries are handled separately from build retries. mriedem suggested a patch to ignore the retry field of the instance request spec during migrations. this patch allowed the failing migration to succeed.
it is important to note that it may fail the migration again, however there is still sufficient reason to ignore the build's failures/retries during a migration.
12:55 < mriedem> it does stand to reason that if this instance failed to build originally on those 2 hosts, that live migrating it there might fail too...but we don't know why it originally failed, could have been a resource claim issue at the time
12:58 < melwitt> yeah, often it's a failed claim. and also what if that compute host is eventually replaced over the lifetime of the cluster, making it a fresh candidate for several instances that might still avoid it because they once failed to build there back when it was a different machine
Changed in nova: | |
importance: | Undecided → Medium |
tags: | added: live-migration |
no longer affects: | nova/newton |
Fix proposed to branch: master /review. openstack. org/505771
Review: https:/