[Openstack-operators] [Openstack] [Neutron] OVS and Linuxbridge insights

Andreas Scheuring scheuran at linux.vnet.ibm.com
Tue Oct 6 07:29:12 UTC 2015


Hi Angel, 
how the vswitches work is perfectly (and for linuxbridge very
extensively) described in those links I sent to you (see mail history).

If you have to choose between those - OVS is the default reference
implementation which supports the full set of features and is the
default in devstack and many other deployment tools as well. So if you
don't have good reasons for using linuxbridge, I would start with ovs.


Devstack is a Openstack Installer that provides you a whole Openstack
installation on a single Node. As the name indicates, it's used for
defvelopment. E.g. the whole Openstack Continues Integration System
(gate) set's up Openstack using devstack to run all the scenario tests. 

You can easily try it out. You just need to clone the git repo [1] and start the install via the stack.sh script.
Devstack then downloads the latest Openstack code from github and installs the Openstack cloud.
This is a guide describing the basics + some scenarios [2]

And for completeness: The local.conf is the configuration file how you configure devstack. E.g. 
you can configure it to use vlan instead of vxlan or things like that.


What is the installation method you're currently using?
It's hard to help you with configuration issues, if I don't know your status quo.
If you don't have any experience with Openstack yet, I think it's good to start with devstack.
Once you have a running system, you can play around and have a look at the config files and ifconfig and so on...


[1] https://github.com/openstack-dev/devstack
[2] http://docs.openstack.org/developer/devstack/



-- 
Andreas
(IRC: scheuran)



On Di, 2015-10-06 at 06:52 +0000, Angel De Andres Pinillos wrote:
> Hi Andreas,
> 
> Thanks a lot for your information.
> 
> I would be interested in how the vswitches work and how to set up the config files.
> What is the devstack local.conf for and where I can find it?
> 
> Thanks a lot for your kind attention and support,
> Angel.
> 
> -----Original Message-----
> From: Andreas Scheuring [mailto:scheuran at linux.vnet.ibm.com] 
> Sent: martes, 06 de octubre de 2015 8:48
> To: Angel De Andres Pinillos
> Subject: Re: [Openstack] [Openstack-operators] [Neutron][Linuxbridge] Problem with configuring linux bridge agent with vxlan networks
> 
> Hi Angel, 
> 
> not sure if you're looking for some insights how the vswitches work or how you set up your config files. And I'm not sure how familar you're with Openstack at all!
> 
> Also of importance is the way how you install your Openstack cloud. E.g if you're using devstack for development you need to configure the devstack local.conf correctly. If you have a commercial deployment tool, you probably need to understand and modify the chef scripts/input params accordingly. 
> 
> What kind of network virtualization technology would you like to use?
> VLAN or VXLAN, GRE? Depending on your choice, you need other config options.
> 
> So if you provide more information what exactly you're looking for, I can try to help out. You can also try to ping me in IRC or if you have concrete questions just ask in the #openstack channel. Otherwise it would be great if we could sent future mails via the Mailinglist!
> 
> 
> Here some information for the beginning:
> 
> 
> Openvswitch internals
> =====================
> http://docs.openstack.org/developer/neutron/devref/openvswitch_agent.html
> 
> This page shows how the openvswitch is set up on a Compute Node. It also has links with further information
> 
> 
> Linuxbridge internals
> =====================
> 
> This is a very good and extensive description also covering things like packet flow along examples.
> 
> http://docs.openstack.org/networking-guide/deploy_scenario1b.html
> 
> 
> 
> Linuxbridge configuration options
> =================================
> All possible options you can find here:
> 
> http://docs.openstack.org/kilo/config-reference/content/networking-plugin-linuxbridge_agent.html
> http://docs.openstack.org/kilo/config-reference/content/networking-plugin-openvswitch_agent.html
> 
> 
> 
> OVS config Examples
> ===================
> Compute Node: this + subpages!:
> http://docs.openstack.org/havana/install-guide/install/apt/content/install-neutron.install-plugin-compute.ovs.html
> 
> Network Node Examples:
> http://docs.openstack.org/havana/install-guide/install/apt/content/neutron-install.dedicated-network-node.html
> 
> 
> 
> 
> --
> Andreas
> (IRC: scheuran)
> 
> 
> 
> On Mo, 2015-10-05 at 12:50 +0000, Angel De Andres Pinillos wrote:
> > Dear Andreas,
> > 
> > I am quite new in Opestack, specialy when it comes to networking.
> > I would highly appreciate if you could send me some information regarding: linux bridges vs OVS and how is set-up the brigdes and OVS.
> > 
> > Thanks a lot in advance for your kind attention and support,
> > Angel.
> > 
> > 
> > -----Original Message-----
> > From: Andreas Scheuring [mailto:scheuran at linux.vnet.ibm.com] 
> > Sent: lunes, 05 de octubre de 2015 10:10
> > To: Sławek Kapłoński
> > Cc: openstack-operators at lists.openstack.org; openstack at lists.openstack.org
> > Subject: Re: [Openstack] [Openstack-operators] [Neutron][Linuxbridge] Problem with configuring linux bridge agent with vxlan networks
> > 
> > Hi Sławek,
> > 
> > virbr0 belongs to the default libvirt network that is set up when you install libvirt. It's not related to Openstack.
> > 
> > You should verify, that the vxlan port is open on both hypervisors (default 4789 udp). This is not set up by Openstack but needs to be done by the deployment tool or the deployer (if upstream Openstack)
> > 
> > In any case it's helpful to debug with tcpdump to see if packets are leaving eth1 and if they are encapsulated. With tcpdump you also should be able to figure out the used port if it is not 4789 (I don't know the lb default)
> > 
> > But as mentioned before, my first guess is the vxlan port that needs to be enabled in iptables by hand on each node (compute & network node).
> > 
> > --
> > Andreas
> > (IRC: scheuran)
> > 
> > 
> > 
> > On Fr, 2015-10-02 at 23:04 +0200, Sławek Kapłoński wrote:
> > > Hello,
> > > 
> > > Yes. I was reading mostly
> > > http://docs.openstack.org/networking-guide/scenario_legacy_lb.html
> > > because imho this is what I want now :). I don't want DVR and L3 HA (at
> > > least for now) but only traffic via vxlan between two vms which are
> > > connected to tenant network (it is probably called east-west traffic,
> > > yes?)
> > > 
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> > 
> > 
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