[Beaker-devel] Questions regarding DHCP/DNS requirements for IPv6 support

Amit Saha asaha at redhat.com
Mon Nov 25 07:23:44 UTC 2013


Hi Nick,

My comments inline and accurate to the best of what I have learned so far.

----- Original Message -----
> From: "Nick Coghlan" <ncoghlan at redhat.com>
> To: "beaker-devel" <beaker-devel at lists.fedorahosted.org>
> Sent: Monday, November 25, 2013 4:15:45 PM
> Subject: [Beaker-devel] Questions regarding DHCP/DNS requirements for IPv6	support
> 
> This is mostly aimed at Amit (since he's been looking into this lately),
> but I've been pondering exactly what is needed from an environmental
> point of view to enable testing of IPv6-only systems directly within Beaker.
> 
> My current understanding of the supporting config Beaker needs to
> support this is below, so my general questions are: a) did I miss
> anything?; and b) is anything I have listed wrong?
> 
> * Main beaker server
> 
> - needs both A and AAAA records assigned in DNS
> - needs to serve the task library yum repo over both IPv4 and IPv6

I believe httpd will need to be configured to listen on all interfaces (IPv4 and IPv6).

> 
> * Lab controllers
> 
> - need both A and AAAA records assigned in DNS
> - beaker-proxy needs to listen on both IPv4 and IPv6 (implemented in 0.14.4)
> - TFTP server needs to be serving over both IPv4 and IPv6
> 
> * NTP servers
> 
> - need to be accessible over both IPv4 and IPv6
> 
> * Test systems
> 
> - need both A and AAAA records to be assigned by DHCP
> - need to be given both IPv4 and IPv6 addresses for the NTP servers
> 
> As far as I am aware, we don't do "push" communications from the LC or
> the main server to the test systems, so we don't care if the test system
> only has IPv4 or IPv6 enabled.
> 
> With this model, the following test scenarios should all be possible
> directly within Beaker rather than requiring external resources:

I am not clear what you mean by "external resources" here.


> 
> * IPv4 only
> 
> - system is provisioned with an IPv4 only OS, or explicitly has IPv6
> support turned off
> - connects to LC, NTP and main server over IPv4
> - users must ssh in over IPv4

The current use case, although IPv6 is not explicitly turned off.

> 
> * IPv6 only
> 
> - system explicitly has IPv6 support turned off
> - connects to LC, NTP and main server over IPv6
> - users must ssh in over IPv6
> - implicitly tests IPv6 only client -> IPv4 or IPv6 server handling
> - to test interaction with IPv6 only server, use a multi-host test

Something we want to do. Right now, what I have working is beah listening 
only on IPv6 sockets, but the system is essentially communicating
with LC and the server using IPv4. Things are working as expected. 

What is not working yet is being able to communicate with the LC after disabling IPv4. This is 
the part I am focussing on now. I believe things are going to be tricky because:

When beah-srv starts, it establishes communication with the LC using IPv4 address. 
Now, once IPv4 is disabled, how does it handle that? I have to see that once we have the
Lab controller IPv6 DNS entries sorted and the beaker-proxy patch is deployed.

Obviously, I haven't experimented with disabling IPv4 on the test system post install, but I will
keep that as the next experiment. This will tell us whether simply having a IPv6 address for
the beaker server and a correctly registered DNS entry will suffice. 

> 
> 
> * IPv4 or IPv6
> 
> - system has both IPv4 and IPv6 support enabled

This is the state now.


> - connects to LC, NTP and main server over IPv4 or IPv6 (OS/client app
> dependent)

I have seen a command line utlity (wget, I think) allows you to specify a preferred address family, 
but I doubt Twisted allows that.

> - users can ssh in over either IPv4 or IPv6 (OS/client app dependent)

Possible right now.

> - implicitly tests IPv4 or IPv6 client -> IPv4 or IPv6 server handling
> - to test interaction with IPv4 only server, use a multi-host test
> - to test interaction with IPv6 only server, use a multi-host test

I am not sure about these three.

Best,
Amit.

-- 
Amit Saha <http://echorand.me>
Software Engineering and Development
Red Hat, Inc.


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