[Dnsmasq-discuss] How does DNSMASQ handle large concurrent configure file updating request requests

[Brian Haley]

On 01/14/2015 04:48 AM, Yongkang You wrote:
> Hi,
> 
> We have a cloud environment which uses DNSMASQ as DHCP/DNS server; in the cloud,
> it usually starts lots of VMs concurrently, for example, 10000 VM; for each VM,
> we will configure a static DHCP entry in DNSMASQ configuration and send SIGUSER1
> to reload. we observe DNSMASQ becomes very busy of reloading, for example, it
> seems to reload 10000 times if we send for 10000 SIGUSER1.
> 
> Is this expected behavior? Is there any way to avoid this? because it keep
> reloading, we don't know if this will effect VM getting IP address.

Just for completeness, is this on Openstack?  I can see that code doesn't buffer
anything when a port is plugged-in, so each triggers a reload.  Could maybe
tweak things there to wait a few seconds between the HUPs.  I'm not sure it's a
bug in dnsmasq though.

-Brian