openstack team mailing list archive

[Christian Parpart <trapni@xxxxxxxxx>]

Hey,

thanks for your reply. Unfortunately there was no process restart in
nova-network nor in dnsmasq,
both processes seem to have been up for about 2 and 3 days.

However, why is the default dhcp_lease_time value equal 120s? Not having
this one overridden
causes the clients to actually re-acquire a new DHCP lease every 42 seconds
(at least on my nodes),
which is completely ridiculous.
OTOH, I took a look at the sources (linux_net.py) and found out, why the
max_lease_time is
set to 2048, because that is the size of my network.
So why is the max lease time the size of my network?
I've written a tiny patch to allow overriding this value in nova.conf, and
will submit it to launchpad
soon - and hope it'll be accepted and then also applied to essex, since
this is a very straight forward
few-liner helpful thing.

Nevertheless, that does not clarify on why now I had 2 (well, 3 actually)
instances getting
no DHCP replies/offers after some hours/days anymore.

The one host that caused issues today (a few hours ago), I fixed it by hard
rebooting the instance,
however, just about 40 minutes later, it again forgot its IP, so one might
say, that it
maybe did not get any reply from the dhcp server (dnsmasq) almost right
after it got
a lease on instance boot.

So long,
Christian.

On Thu, Jun 14, 2012 at 10:55 PM, Nathanael Burton <
nathanael.i.burton@xxxxxxxxx> wrote:

> Has nova-network been restarted? There was an issue where nova-network was
> signalling dnsmasq which would cause dnsmasq to stop responding to requests
> yet appear to be running fine.
>
> You can see if killing dnsmasq, restarting nova-network, and rebooting an
> instance allows it to get a dhcp address again ...
>
> Nate
> On Jun 14, 2012 4:46 PM, "Christian Parpart" <trapni@xxxxxxxxx> wrote:
>
>> Hey all,
>>
>> I feel really sad with saying this, now, that we have quite a few
>> instances in producgtion
>> since about 5 days at least, I now have encountered the second instance
>> loosing its
>> IP address due to "No DHCPOFFER" (as of syslog in the instance).
>>
>> I checked the logs in the central nova-network and gateway node and found
>> dnsmasq still to reply on requests from all the other instances and it
>> even
>> got the request from the instance in question and even sent an OFFER, as
>> of what
>> I can tell by now (i'm investigating / posting logs asap), but while it
>> seemed
>> that the dnsmasq sends an offer, the instances says it didn't receive one
>> - wtf?
>>
>> Please tell me what I can do to actually *fix* this issue, since this is
>> by far very fatal.
>>
>> One chance I'd see (as a workaround) is, to let created instanced retrieve
>> its IP via dhcp, but then reconfigure /etc/network/instances to continue
>> with
>> static networking setup. However, I'd just like the dhcp thingy to get
>> fixed.
>>
>> I'm very open to any kind of helping comments, :)
>>
>> So long,
>> Christian.
>>
>>
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