[Openstack-operators] [dnsmasq] setting ntp-server

Carlos Konstanski ckonstanski at pippiandcarlos.com
Fri Aug 18 23:13:10 UTC 2017

tldr; you have to use an IP address, not a DNS name, in the ntp-server

In dhcp_agent.ini:

    dnsmasq_config_file = /etc/neutron/dnsmasq.conf

In /etc/neutron/dnsmasq.conf:


I was trying to use a <dns_name> instead of an <ip_address> . The result
was that the floating IP was not being wired correctly. Packets were not
making it to the qr device. Not sure why.

But with an IP address, everything works and a
/var/lib/ntp/ntp.conf.dhcp gets written. As long as the /etc/init.d/ntp
script looks for this file, everything is golden.


Carlos Konstanski <ckonstanski at pippiandcarlos.com> writes:

> I am searching for a way to set NTP servers in instances. Thre are at
> least two ways to do this that come to mind: DHCP and cloud.cfg. I would
> like to explore DHCP for this discussion.
> dnsmasq supports the following configuration:
>     dhcp-option=option:ntp-server,<host1>,<host2>,...
> In the Ubuntu /etc/init.d/ntp service script the following can be found:
>     if [ /var/lib/ntp/ntp.conf.dhcp -nt /etc/ntp.conf ]; then
>         NTPD_OPTS="$NTPD_OPTS -c /var/lib/ntp/ntp.conf.dhcp"
>     fi
> It would seem that the two work together to allow DHCP to override
> /etc/ntp.conf.
> The question is how to get openstack to configure dnsmasq thusly. There
> are two possibilities: a neutron config option or the overriding of the
> entire dnsmasq.conf. The former would be mch simpler and less messy. Is
> there such a setting in neutron.conf?
> Carlos Konstanski
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> OpenStack-operators mailing list
> OpenStack-operators at lists.openstack.org
> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-operators

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