Neutron dhcp-agent scalability techniques

Julia Kreger juliaashleykreger at
Tue Oct 8 16:28:45 UTC 2019

While not necessarily direct scaling of that subnet, you may want to
look at ironic.conf's [neutron]port_setup_delay option. The default
value is zero seconds, but increasing that value will cause the
process to pause a little longer to give time for the neutron agent
configuration to update, as the agent may not even know about the
configuration as there are multiple steps with-in neutron, by the time
the baremetal machine tries to PXE boot. We're hoping that in the U
cycle, we'll finally have things in place where neutron tells ironic
that the port setup is done and that the machine can be powered-on,
but not all the code made it during Train.


On Tue, Oct 8, 2019 at 9:15 AM fsbiz at <fsbiz at> wrote:
> Hi folks,
> We have a rather large flat network consisting of over 300 ironic baremetal nodes
> and are constantly having the baremetals timing out during their PXE boot due to
> the dhcp agent not able to respond in time.
> Looking for inputs on successful DHCP scaling techniques that would help mitigate this.
> thanks,
> Fred.

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