neutron/releasenotes/notes/dhcp-resync-throttle-config-option-9f2375e3baf683ad.yaml
Kailun Qin 1d98f0a7d4 Event driven periodic resync task for DHCP agents
The DHCP agent will resync its state with Neutron to recover from any
transient notification or RPC errors. Currently, the periodic resync
task waits on a timer to determine whether a re-sync is necessary. The
interval between attempts by default is 5 seconds and can be longer
thru config. This may cause a potentially long delay before an agent
gets new work via an agent_updated RPC call.

The idea of this RFE is to change the timer based periodic resync task
into an event driven one. It also proposes a new DHCP agent config
option "resync_throttle" to ensure the minimum interval taken between
resync state events to avoid too frequent resyncing. In this way, we
could force the agent to act on the resync request immediately therefore
decreasing how much time is needed before DHCP services are available.

Co-authored-by: Allain Legacy <Allain.legacy@windriver.com>

Closes-Bug: #1780370
Change-Id: Ie9d758ba5f750a38dc19ea5ce8b2c6b414f9ef80
2018-10-26 01:24:24 +08:00

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YAML

---
features:
-
A new config option ``resync_throttle`` has been added for Neutron DHCP
agent.
This new option allows to throttle the number of resync state events
between the local DHCP state and Neutron to only once per
``resync_throttle`` seconds.
Default value for this new option is set to 1 and it should be configured
per a user's specific scenario, i.e. how responsive the user would like
his/her system to be for those DHCP resync state events.
The option is introduced together with the event driven periodic task for
DHCP agents. This enhances the agent with a faster reaction on the resync
request but ensuring a minimum interval taken between them to avoid too
frequent resyncing.
For more information see bug
`1780370 <https://bugs.launchpad.net/neutron/+bug/1780370>`_.