[openstack-dev] [Magnum] TLS Support in Magnum

Steven Dake (stdake) stdake at cisco.com
Wed Jun 17 02:40:25 UTC 2015


Answering Clint’s question, yes there is a reason all nodes must expose a floating IP address.

In a Kubernetes cluster, each minion has a port address space.  When an external service contacts the floating IP’s port, the request is routed over the internal network to the correct container using a proxy mechanism.  The problem then is, how do you know which minion to connect to with your external service?  The answer is you can connect to any of them.  Kubernetes only has one port address space, so Kubernetes suffers from a single namespace problem (which Magnum solves with Bays).

Longer term it may make sense to put the minion external addresses on a RFC1918 network, and put a floating VIF with a load balancer to connect to them.  Then no need for floating address per node.  We are blocked behind kubernetes implementing proper support for load balancing in OpenStack to even consider this work.


From: <Fox>, Kevin M <Kevin.Fox at pnnl.gov<mailto:Kevin.Fox at pnnl.gov>>
Reply-To: "OpenStack Development Mailing List (not for usage questions)" <openstack-dev at lists.openstack.org<mailto:openstack-dev at lists.openstack.org>>
Date: Tuesday, June 16, 2015 at 6:36 AM
To: "OpenStack Development Mailing List (not for usage questions)" <openstack-dev at lists.openstack.org<mailto:openstack-dev at lists.openstack.org>>
Subject: Re: [openstack-dev] [Magnum] TLS Support in Magnum

Out of the box, vms usually can contact the controllers though the routers nat, but not visa versa. So its preferable for guest agents to make the connection, not the controller connect to the guest agents. No floating ips, security group rules or special networks are needed then.


From: Clint Byrum
Sent: Monday, June 15, 2015 6:10:27 PM
To: openstack-dev
Subject: Re: [openstack-dev] [Magnum] TLS Support in Magnum

Excerpts from Fox, Kevin M's message of 2015-06-15 15:59:18 -0700:
> No, I was confused by your statement:
> "When we create a bay, we have an ssh keypair that we use to inject the ssh public key onto the nova instances we create."
> It sounded like you were using that keypair to inject a public key. I just misunderstood.
> It does raise the question though, are you using ssh between the controller and the instance anywhere? If so, we will still run into issues when we go to try and test it at our site. Sahara does currently, and we're forced to put a floating ip on every instance. Its less then ideal...

Why not just give each instance a port on a network which can route
directly to the controller's network? Is there some reason you feel
"forced" to use a floating IP?

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