[openstack-dev] [nova][neutron][devstack] New proposed 'default' network model

Doug Wiegley dougwig at parksidesoftware.com
Tue Sep 15 22:49:23 UTC 2015



> On Sep 15, 2015, at 4:11 PM, Mathieu Gagné <mgagne at internap.com> wrote:
> 
>> On 2015-09-15 2:00 PM, Fox, Kevin M wrote:
>> We run several clouds where there are multiple external networks. the "just run it in on THE public network" doesn't work. :/
>> 
>> I also strongly recommend to users to put vms on a private network and use floating ip's/load balancers. For many reasons. Such as, if you don't, the ip that gets assigned to the vm helps it become a pet. you can't replace the vm and get the same IP. Floating IP's and load balancers can help prevent pets. It also prevents security issues with DNS and IP's. Also, for every floating ip/lb I have, I usually have 3x or more the number of instances that are on the private network. Sure its easy to put everything on the public network, but it provides much better security if you only put what you must on the public network. Consider the internet. would you want to expose every device in your house directly on the internet? No. you put them in a private network and poke holes just for the stuff that does. we should be encouraging good security practices. If we encourage bad ones, then it will bite us later when OpenStack gets a reputation for being associated with compromises.
> 
> Sorry but I feel this kind of reply explains why people are still using
> nova-network over Neutron. People want simplicity and they are denied it
> at every corner because (I feel) Neutron thinks it knows better.

Please stop painting such generalizations.  Go to the third or fourth email in this thread and you will find a spec, worked on by neutron and nova, that addresses exactly this use case.

It is a valid use case, and neutron does care about it. It has wrinkles. That has not stopped work on it for the common cases.

Thanks,
Doug 


> 
> The original statement by Monty Taylor is clear to me:
> 
> I wish to boot an instance that is on a public network and reachable
> without madness.
> 
> As of today, you can't unless you implement a deployer/provider specific
> solution (to scale said network). Just take a look at what actual public
> cloud providers are doing:
> 
> - Rackspace has a "magic" public network
> - GoDaddy has custom code in their nova-scheduler (AFAIK)
> - iWeb (which I work for) has custom code in front of nova-api.
> 
> We are all writing our own custom code to implement what (we feel)
> Neutron should be providing right off the bat.
> 
> By reading the openstack-dev [1], openstack-operators [2] lists, Neutron
> specs [3] and the Large Deployment Team meeting notes [4], you will see
> that what is suggested here (a scalable public shared network) is an
> objective we wish but are struggling hard to achieve.
> 
> People keep asking for simplicity and Neutron looks to not be able to
> offer it due to philosophical conflicts between Neutron developers and
> actual public users/operators. We can't force our users to adhere to ONE
> networking philosophy: use NAT, floating IPs, firewall, routers, etc.
> They just don't buy it. Period. (see monty's list of public providers
> attaching VMs to public network)
> 
> If we can accept and agree that not everyone wishes to adhere to the
> "full stack of networking good practices" (TBH, I don't know how to call
> this thing), it will be a good start. Otherwise I feel we won't be able
> to achieve anything.
> 
> What Monty is explaining and suggesting is something we (my team) have
> been struggling with for *years* and just didn't have bandwidth (we are
> operators, not developers) or public charisma to change.
> 
> I'm glad Monty brought up this subject so we can officially address it.
> 
> 
> [1] http://lists.openstack.org/pipermail/openstack-dev/2015-July/070028.html
> [2]
> http://lists.openstack.org/pipermail/openstack-operators/2015-August/007857.html
> [3]
> http://specs.openstack.org/openstack/neutron-specs/specs/liberty/get-me-a-network.html
> [4]
> http://lists.openstack.org/pipermail/openstack-operators/2015-June/007427.html
> 
> -- 
> Mathieu
> 
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