openstack team mailing list archive

[Édouard Thuleau <thuleau@xxxxxxxxx>]

Hi Vish,

The code was merge to the master
(https://github.com/openstack/nova/commit/d5b91dd39bd89eed98742cd02ea604a842a45447)
yesterday.

But the bug with rule removal wasn't fix. I'll open a bug. But I try
to investigate it and I don't find the problem.
Could you help me ?

Regards,
Édouard.

On Fri, Dec 7, 2012 at 6:45 PM, Édouard Thuleau <thuleau@xxxxxxxxx> wrote:
> The code doesn't make lot of change to the nova network manager code. It
> modifies principally the linux_net driver code.
>
> And I don't think we can consider it like a new feature. I think it's more a
> bug fix.
>
> In VLAN manger mode, if we plan to carry 4000 tenants in our cloud, we need
> to use 4000 networks and, consequently, 4000 VLANs on all the datacenter
> network. But the actual switch equipment cannot carry a trunk of 4000 VLAN
> to all compute host (for example, Cisco Nexus 5500 can not enabled more than
> 32000 logical interfaces[1] (= TRUNKS x VLANS + ACCESS_PORTS [2])).
> If nova network tear down unused networks, it would be possible to plug a
> mechanism on it to delete unused VLAN on the switch port. And we can
> provisioning dynamically VLANs on switch ports and don't exceed the logical
> interface limitation of networks equipments.
>
> [1]http://www.cisco.com/en/US/docs/switches/datacenter/nexus5000/sw/configuration_limits/limits_513/nexus_5000_config_limits_513.html#wp344401
> [2]
> http://jpmcauley.com/2011/06/23/vlan-port-instance-limitation-on-cisco-ucs/
>
>
>
> On Mon, Dec 3, 2012 at 11:50 PM, Vishvananda Ishaya <vishvananda@xxxxxxxxx>
> wrote:
>>
>> FYI, this patch is probably something bigger than we can merge.
>> Nova-network is supposed to just be in maintenance mode and
>> not getting big new features. Small features are ok, but this one changes
>> a lot of lines.
>>
>> Not sure what is up with your rule removal. Perhaps there are multiple
>> copies of the added rules so they aren't being deleted properly? In fact,
>> that may be a bug. It looks like plug is called for each vm so we might end
>> up with multiple copies of the isolation rules.
>>
>> Vish
>>
>> On Dec 3, 2012, at 6:34 AM, Édouard Thuleau <thuleau@xxxxxxxxx> wrote:
>>
>> Hi Vish,
>>
>> I made a patch to implement that with the VLAN manager:
>> https://review.openstack.org/#/c/17352/
>>
>> I put a lock on methods '_setup_network_on_host' and
>> '_teardown_network_on_host' of class 'VlanManager' and I reused (and
>> renamed) the locks already defined in class 'LinuxBridgeInterfaceDriver'
>> when a bridge or VLAN is created ('ensure_vlan' => 'lock_vlan' and
>> 'unsure_bridge' => 'lock_bridge'). Do you think is enough to prevent any
>> race condition ?
>>
>> I've got a bug. I create method '_remove_dnsmasq_accept_rules' to remove
>> filter rules for DHCP server but when I call it, nothing is deleted. Could
>> you help me to resolve that ? And I've got the same problem sometimes with
>> method 'remove_isolate_dhcp_address'. The ebtables rules are correctly
>> deleted but not  for iptables rules.
>>
>> I didn't delete a network bridge if it handles VPN forward rules of the
>> private network even if no VM use this gateway on the host. But if a network
>> is deleted, nothing will tear down this gateway.
>> I think I found another bug. If network host must handle the VPN forward
>> rules for a private network and if we restart it, it should instantiate a
>> gateway on this private network and add VPN forward rules even if no VM use
>> this gateway on the host. But actually  it doesn't do that. Perhaps, the
>> method 'db.network_get_all_by_host' use in 'init-host' must return the
>> network in this case ?
>>
>> I only implement this for the multi hosted networks with the VLAN manger.
>> I think isn't useful to add this on the multi hosted network with the Flat
>> DHCP manager because, in this mode, only one multi hosted network is created
>> for all instances of all tenants.
>>
>> Regards,
>> Édouard.
>>
>> On Wed, Nov 21, 2012 at 12:49 AM, Vishvananda Ishaya
>> <vishvananda@xxxxxxxxx> wrote:
>> > The only reason this is not done is that it makes the setup simpler. We
>> > don't have to worry about potential races between setting up and tearing
>> > down interfaces. It probably wouldn't be incredibly difficult to make a
>> > patch that would remove them, but you will likely have to do some
>> > creative
>> > locking to make sure that you don't run into issues.
>> >
>> > Vish
>> >
>> > On Nov 20, 2012, at 9:25 AM, Édouard Thuleau <thuleau@xxxxxxxxx> wrote:
>> >
>> >> Hi all,
>> >>
>> >> I use nova-network with VLAN manager.
>> >>
>> >> Why nova-network doesn't remove unused network interfaces on a host ?
>> >>
>> >> ie, if none VM on a host have a fixed IP attach to network X, the VLAN
>> >> and bridge of this network still up and unused. And 'dnsmasq' process
>> >> still listen and running.
>> >>
>> >> The number of unused network interfaces will grow over time.
>> >> In the VLAN mode, this number could be 4000 x 2 unused interfaces and
>> >> 4000 unused 'dnsmasq' processes (in worth case).
>> >>
>> >> Can it lead to decrease the kernel performance ?
>> >> Is it a bug ? Or a voluntary implementation ?
>> >>
>> >> Regards,
>> >> Édouard.
>> >>
>> >> _______________________________________________
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>> >
>>
>>
>