openstack team mailing list archive

[Leander Bessa Beernaert <leanderbb@xxxxxxxxx>]

Hello all,

I've had a few reports from users testing out the sample installation of
OpenStack  i setup. The reports were all related to problems with inter-vm
network speeds and connection timeouts as well as the inability to connect
to the outside word from within the VM (e.g.: ping www.google.com). I'm not
sure if i setup something wrong, so i have a few questions.

The current installation of OpenStack is running with 1 controller node,
and 8 compute nodes. Each node is running Ubuntu 12.04 and Essex with the
default packages. I'm using the VLAN network manager. There is one
peculiarity to this setup. Since each physical hosts only has 1 network
interface,  i came up with the following configuration:
  - For inter-node communications i set up  a VLAN with the ID 107
  - Each tentant has it's private network on a separate VLAN. Currently
there are two tenant, one on VLAN 109 (network: 10.0.9.0/24) and another on
VLAN 110 (network: 10.0.9.0/24).

I'm not a network expert, so please bear with me if i make any outrages
statements.

1) When communicating on the private network, the packets are not routed
through the controller right? That only happens when the VM needs to
contact an external source (e.g.: google), correct? This report originated
from users from VLAN 109. They are using network intensive applications
which send a lot of data between each of the instances. They reported
various time-out and connection drops as well as slow transfer speeds. I'm
no network expert, but could this be related to the routing, VLANs or is it
a hardware issue?

2) I've noticed that for external access (e.g.: google), all the packets
seem to be routed through the nova-network on the controller node. If i
setup a multi-host setup (install nova-network and nova-api-metadata on
each compute node), the external packets no lounger need to be routed
through the controller node right?

3) The setup has been running for about 1 month and a half. During that
time, VMs on VLAN 109 could never reach the internet. However, VLAN 110
worked just fine. Today, out of nowhere, VMs on VLAN 109 can suddenly reach
the internet. I didn't touch or change anything since the initial setup, it
simply happend. Before this bizarre occurrence i've sat down with our
network specialist and told me that, based on the routing rule in iptables,
this problem (VMs on VLAN 109 not being able to connect to the internet)
should not be happening. Has this ever occurred to any of you?


Thanks in advance.

-- 
Cumprimentos / Regards,
Leander