DHCP timeout when creating instances for specific tenants
Grant Morley
grant at civo.com
Thu Dec 5 11:38:36 UTC 2019
Hi all,
It looks like the issue was actually with the Ubuntu image for both
16.04 and 18.04. We changed the dhcp timeout in
"/etc/dhcp/dhclient.conf" from 300 seconds down to 2 seconds and the
instances then worked absolutely fine. Not sure why it was only
happening for some tenants and not others but that has resolved it.
I am still going to look into the metadata service as the fix doesn't
feel right to me still.
Thanks again for all your help.
Grant
On 05/12/2019 00:09, Laurent Dumont wrote:
> Maybe the following could provide a bit more data :
>
> * Launch a test instance in the tenant project experiencing the issue.
> * tcpdump directly on the instance TAP interface - confirm if you
> are seeing DHCP DISCOVER/REQUEST/OFFER
> * Would also allow you to see the Cloudinit traffic.
>
>
> On Wed, Dec 4, 2019 at 7:06 PM Grant Morley <grant at civo.com
> <mailto:grant at civo.com>> wrote:
>
> Hi Cory,
>
> Thanks for the response. I'll take a look at the metadata service
> from the instance and from OpenStack itself tomorrow now. It's
> midnight here in the UK and I need to get some rest. Thanks for
> the tip, hopefully I'll find something useful to go on from there.
>
> Grant,
>
> On 04/12/2019 23:49, Cory Hawkless wrote:
>>
>> Are they failing to contact the metadata service and hanging
>> during the boot process while they try and receive metadata?
>>
>> From the VM can you hit http://169.254.169.254 – That’s the
>> default IP of the metadata server, it should respond with a basic
>> page showing some date based subdirectories
>>
>> If it doesn’t respond you can start following the metadata
>> service path instead of DHCP
>>
>> Given that the machines come up with an IP eventually leads me to
>> think the DHCP service is actually working ok.
>>
>> *From:*Grant Morley [mailto:grant at civo.com]
>> *Sent:* Thursday, 5 December 2019 10:10 AM
>> *To:* Eric K. Miller <emiller at genesishosting.com>
>> <mailto:emiller at genesishosting.com>;
>> openstack-operators at lists.openstack.org
>> <mailto:openstack-operators at lists.openstack.org>
>> *Cc:* Ian Banks <ian at civo.com> <mailto:ian at civo.com>
>> *Subject:* Re: DHCP timeout when creating instances for specific
>> tenants
>>
>> Hi Eric,
>>
>> Thanks for getting back to me. I am fairly sure it is a DHCP
>> error. The instances are getting an IP when they eventually boot,
>> it is just taking a long time for them to bring up networking.
>> The strange thing is, it only seems to be new tenants. All
>> existing tenants are absolutely fine.
>>
>> I can check DNS as well just to be on the safe side, however I
>> wasn't seeing any errors in the Nova or Neutron logs when the
>> instance(s) were being created.
>>
>> Regards,
>>
>> On 04/12/2019 22:47, Eric K. Miller wrote:
>>
>> Hi Grant,
>>
>> Are you sure this is a DHCP timeout and not a DNS resolution
>> issue? I ask because we have seen a strange DNS issue occur
>> that can cause something similar.
>>
>> Are the VMs being assigned an IP after they finally boot?
>>
>> Eric K. Miller
>>
>> Genesis Hosting Solutions, LLC
>>
>> Try our Genesis Public Cloud - powered by OpenStack!eut
>>
>> https://genesishosting.com/
>>
>> *From:*Grant Morley [mailto:grant at civo.com]
>> *Sent:* Wednesday, December 04, 2019 11:00 AM
>> *To:* openstack-operators at lists.openstack.org
>> <mailto:openstack-operators at lists.openstack.org>
>> *Cc:* Ian Banks
>> *Subject:* DHCP timeout when creating instances for specific
>> tenants
>>
>> Hi all,
>>
>> I wonder if anyone can help shed any light on an odd issue we
>> are seeing with only a couple of specific tenants. Basically
>> if they launch an instance they are taking about 5 minutes to
>> launch rather than our usual 30 second or so launch.
>>
>> We are seeing the following on the instance logs:
>>
>> https://pastebin.com/hDstsd8G
>>
>> Weirdly it only seems to be happening for 1 or 2 new tenants.
>> I have tested this on our personal account and a few other
>> customers have tested and their instances launch really
>> quickly as expected.
>>
>> Is there anything specific during the tenant creation that
>> can cause this issue? Or are there any logs in nova / neutron
>> I should be looking out for that might shed some light?
>>
>> I haven't seen anything that is obvious. Any help would be
>> much appreciated as we are a little stumped at the moment.
>>
>> Many thanks,
>>
>> --
>>
>> Grant Morley
>>
>> Cloud Lead, Civo Ltd
>>
>> www.civo.com <https://www.civo.com/>| Signup for an account!
>> <https://www.civo.com/signup>
>>
--
Grant Morley
Cloud Lead, Civo Ltd
www.civo.com <https://www.civo.com/>| Signup for an account!
<https://www.civo.com/signup>
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