[Openstack] Can't access instances from specific compute node

Marcos Nóbrega marcosnobregajr at gmail.com
Tue Oct 27 12:31:46 UTC 2015


The problem was really a MTU issue, we changed the DHCP agent configuration
to change the MTU as described in the section
*To configure the DHCP agent* (
http://docs.openstack.org/kilo/install-guide/install/apt/content/neutron-network-node.html
)
and now it's working!


Thanks a lot Rahul!

2015-10-26 21:12 GMT-03:00 Rahul Sharma <rahulsharmaait at gmail.com>:

> Since ping and telnet works to machine B, then it seems to be an MTU
> issue. Try sending ping packets of large size, they might fail in your
> case. You can see what is happening in ssh by doing "ssh -vvv machineB" and
> will see that its unable to get the key ( > 1500 in length). There are
> different MTU fixes available, you can find them on the internet. When we
> faced such issue, we disabled Large Receive Offload(LRO) on the nic of
> compute node. In your case, it might be issue with nic, or maybe with
> upstream switch, you can debug it out and see if it works.
>
> Thanks.
>
> *Rahul Sharma*
> *MS in Computer Science, 2016*
> College of Computer and Information Science, Northeastern University
> Mobile:  801-706-7860
> Email: rahulsharmaait at gmail.com
> Linkedin: www.linkedin.com/in/rahulsharmaait
>
> On Mon, Oct 26, 2015 at 5:45 PM, Marcos Nóbrega <marcosnobregajr at gmail.com
> > wrote:
>
>> Hello all,
>>
>> We are using OpenStack Kilo in the following deployment:
>>
>> Computer A:
>>
>>  - Controller node
>>  - Network node
>>  - Compute node
>>  - Only one network interface
>>
>> Computer B:
>>
>>  - Compute node
>>  - Only one network interface
>>
>> Instances created in the computer A works fine, and we are able to
>> connect via SSH, but instances from computer B we can't connect, only ping
>> and telnet works.
>>
>> If anyone could help us with tips to investigate this problem.
>>
>> Thanks.
>>
>>
>>
>> --
>> *Marcos Nóbrega*
>> Desenvolvedor no Laboratório de Sistemas Distribuídos (LSD-UFCG)
>> Bacharel em Sistemas de Informação (FIP)
>>
>>
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>>
>


-- 
*Marcos Nóbrega*
Desenvolvedor no Laboratório de Sistemas Distribuídos (LSD-UFCG)
Bacharel em Sistemas de Informação (FIP)
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