DHCPNAK after neutron-dhcp-agent restart
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
Mirantis OpenStack |
Invalid
|
High
|
Andrew Woodward | ||
6.0.x |
Invalid
|
High
|
Andrew Woodward | ||
6.1.x |
Invalid
|
High
|
Alexey Khivin |
Bug Description
(backport of https:/
After rolling out a configuration change, we restarted neutron-dhcp-agent service, and then dnsmasq logs start flooding: DHCPNAK ... lease not found.
DHCPNAK is replied by dnsmasq for all DHCPREQUEST renews from all VMs. However the MAC and IP pairs exist in host files.
The log flooding increases when more and more VMs start renewing and they keep retrying until IP expire and send DHCPDISCOVER and reinit the IP.
The log flooding gradually disappears when the VMs IP expire and send DHCPDISCOVER, to which dnsmasq respond DHCPOFFER properly.
Analysis:
I noticed that option --leasefile-ro is used in dnsmasq command when started by neutron dhcp-agent. According to dnsmasq manual, this option should be used together with --dhcp-script to customize the lease database. However, the option --dhcp-script was removed when fixing bug 1202392.
Because of this, dnsmasq will not save lease information in persistent storage, and when it is restarted, lease information is lost.
Solution:
Simply replace --leasefile-ro by --dhcp-
Changed in mos: | |
status: | Confirmed → New |
milestone: | none → 7.0 |
The fix for this bug is available in upstream stable/kilo branch and has been already backported to MOS. /github. com/openstack/ neutron/ commit/ c07687c98570360 9ccc80f0151a2a4 0e2036a3f4
The commit is https:/