nova/releasenotes/notes/bug-1996995-qemu_monitor_announce_self-add-configurables-2b2f19d238442f72.yaml
as0 fba851bf3a Add further workaround features for qemu_monitor_announce_self
In some cases on Arista VXLAN fabrics, VMs are inaccessible via network
after live migration, despite garps being observed on the fabric itself.

This patch builds on the feature
``[workarounds]/enable_qemu_monitor_announce_self`` feature as reported
in `bug 1815989 <https://bugs.launchpad.net/nova/+bug/1815989>`

This patch adds the ability to config the number of times the QEMU
announce_self monitor command is called, and add a new configuration option to
specify a delay between calling the announce_self command multiple times,
as in some cases, multiple announce_self monitor commands are required for
the fabric to honor the garp packets and the VM to become accessible via
the network after live migration.

Closes-Bug: #1996995
Change-Id: I2f5bf7c9de621bb1dc7fae5b3374629a4fcc1f46
2023-01-30 15:44:44 +00:00

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YAML

---
fixes:
- |
Fixes `bug 1996995`_ in which VMs live migrated on certain VXLAN Arista
network fabrics were inaccessible until the switch arp cache expired.
A Nova workaround option of ``enable_qemu_monitor_announce_self`` was added
to fix `bug 1815989`_ which when enabled would interact with the QEMU
monitor and force a VM to announce itself.
On certain network fabrics, VMs that are live migrated remain inaccessible
via the network despite the QEMU monitor announce_self command successfully
being called.
It was noted that on Arista VXLAN fabrics, testing showed that it required
several attempts of running the QEMU announce_self monitor command before
the switch would acknowledge a VM's new location on the fabric.
This fix introduces two operator configurable options.
The first option sets the number of times the QEMU monitor announce_self
command is called - ``qemu_announce_self_count``
The second option allows operators to set the delay between the QEMU
announce_self commands in seconds for subsequent announce_self commands
with ``qemu_announce_self_interval``
.. _`bug 1996995`: https://bugs.launchpad.net/nova/+bug/1996995
.. _`bug 1815989`: https://bugs.launchpad.net/nova/+bug/1815989