MTU value is incorrect for tenant networks on clusters with Neutron VLAN

[Sergey Kolekonov]

Steps to reproduce:
- Deploy MOS 9.0 cluster (Fuel 9.0 #250) with Neutron+VLAN and non-default MTU value fror private Fuel network (e.x. 9000)
- Spawn a VM and check MTU on its interface (eth)
Expected results:
MTU is equal to value set for Fuel private network
Actual result:
MTU value is default (1500)

The reason is incorrect Neutron configuration:
In /etc/neutron/plugin.ini
physical_network_mtus =physnet1:1500,physnet2:1500

Should be physical_network_mtus =physnet1:1500,physnet2:9000

These values are calculated by osnailyfacter/lib/puppet/parser/functions/generate_physnet_mtus.rb

[Aleksandr Didenko (adidenko)]

Puppet function works as expected (which is also proven by unit tests), the problem here is in Nailgun. When we set MTU=9000 for interface with private network (enp0s6) it creates the following transformation in network_scheme:

 {"action"=>"add-port", "bridge"=>"br-aux", "name"=>"enp0s6"},

And it leads to "physical_network_mtus=physnet1:1500,physnet2:1500" in /etc/neutron/plugins/ml2/ml2_conf.ini. In order to change it to "physical_network_mtus=physnet1:1500,physnet2:9000"
this transformation should look like this:

  {"action"=>"add-port", "bridge"=>"br-aux", "name"=>"enp0s6", "mtu"=>"9000"},

[Aleksandr Didenko (adidenko)]

Diagnostic snapshot attached

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/320942

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/mitaka
Review: https://review.openstack.org/320979

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/320942
Committed: https://git.openstack.org/cgit/openstack/fuel-library/commit/?id=6f349870a39cac2d06f8629dfad5770b28a95cfd
Submitter: Jenkins
Branch: master

commit 6f349870a39cac2d06f8629dfad5770b28a95cfd
Author: Sergey Vasilenko <email address hidden>
Date: Tue May 24 17:58:54 2016 +0300

    Add ability to calculate MTU for bridge,

    if MTU described only into "interfaces" section

    Also convert fixtures to YAML format

    Change-Id: Idfa4cbd5672a21d651be349b9b3602b0498173e5
    Closes-bug: #1575762

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/320979
Committed: https://git.openstack.org/cgit/openstack/fuel-library/commit/?id=3c3dd6a4fd1437233e3a7794621a316e6d9e39b7
Submitter: Jenkins
Branch: stable/mitaka

commit 3c3dd6a4fd1437233e3a7794621a316e6d9e39b7
Author: Sergey Vasilenko <email address hidden>
Date: Tue May 24 17:58:54 2016 +0300

    Add ability to calculate MTU for bridge,

    if MTU described only into "interfaces" section

    Also convert fixtures to YAML format

    Change-Id: Idfa4cbd5672a21d651be349b9b3602b0498173e5
    Closes-bug: #1575762

[Ekaterina Shutova (eshutova)]

Used scenarion from description:
On created VM:
$ ifconfig
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 9000

Verified on:
cat /etc/fuel_build_id:
 455
cat /etc/fuel_build_number:
 455
cat /etc/fuel_release:
 9.0
cat /etc/fuel_openstack_version:
 mitaka-9.0