Re: [patch 3/4] Network namespaces: IPv4 FIB/routing in namespaces

4 messages, 4 authors, 2006-06-28 · open the first message on its own page

Re: [patch 3/4] Network namespaces: IPv4 FIB/routing in namespaces

From: Andrey Savochkin <hidden>
Date: 2006-06-28 14:30:19

Daniel,

On Wed, Jun 28, 2006 at 03:51:32PM +0200, Daniel Lezcano wrote:
Daniel Lezcano wrote:
quoted
Andrey Savochkin wrote:
quoted
Structures related to IPv4 rounting (FIB and routing cache)
are made per-namespace.
Hi Andrey,

if the ressources are private to the namespace, how do you will handle 
NFS mounted before creating the network namespace ? Do you take care of 
that or simply assume you can't access NFS anymore ?
This is a question that brings up another level of interaction between
networking and the rest of kernel code.
Solution that I use now makes the NFS communication part always run in
the root namespace.  This is discussable, of course, but it's a far more
complicated matter than just device lists or routing :)

Best regards

Andrey

Re: [patch 3/4] Network namespaces: IPv4 FIB/routing in namespaces

From: Kirill Korotaev <hidden>
Date: 2006-06-28 14:36:01

quoted
quoted
quoted
Structures related to IPv4 rounting (FIB and routing cache)
are made per-namespace.
Hi Andrey,

if the ressources are private to the namespace, how do you will handle 
NFS mounted before creating the network namespace ? Do you take care of 
that or simply assume you can't access NFS anymore ?

This is a question that brings up another level of interaction between
networking and the rest of kernel code.
Solution that I use now makes the NFS communication part always run in
the root namespace.  This is discussable, of course, but it's a far more
complicated matter than just device lists or routing :)
if we had containers (not namespaces) then it would be also possible to 
run NFS in context of the appropriate container and thus each user could 
  mount NFS itself with correct networking context.

it's another thing which ties subsytems and makes namespaces ugly :/

Kirill

Re: [patch 3/4] Network namespaces: IPv4 FIB/routing in namespaces

From: Daniel Lezcano <hidden>
Date: 2006-06-28 16:57:38

Kirill Korotaev wrote:
quoted
quoted
quoted
quoted
Structures related to IPv4 rounting (FIB and routing cache)
are made per-namespace.

Hi Andrey,

if the ressources are private to the namespace, how do you will 
handle NFS mounted before creating the network namespace ? Do you 
take care of that or simply assume you can't access NFS anymore ?


This is a question that brings up another level of interaction between
networking and the rest of kernel code.
Solution that I use now makes the NFS communication part always run in
the root namespace.  This is discussable, of course, but it's a far more
complicated matter than just device lists or routing :)
if we had containers (not namespaces) then it would be also possible to 
run NFS in context of the appropriate container and thus each user could 
 mount NFS itself with correct networking context.
I was asking the question because in some case, we want a lightweight 
container for running applications (aka application container) who need 
to share the filesystem and it will be too bad to have a network 
namespace which brings isolation and prevents to implement application 
containers. By the way, I agree from a point of view of a system 
container, a complete network isolation is perfect.

Regards.

Daniel.

Re: [patch 3/4] Network namespaces: IPv4 FIB/routing in namespaces

From: Ben Greear <hidden>
Date: 2006-06-28 17:13:24

Daniel Lezcano wrote:
Kirill Korotaev wrote:
quoted
quoted
quoted
quoted
quoted
Structures related to IPv4 rounting (FIB and routing cache)
are made per-namespace.


Hi Andrey,

if the ressources are private to the namespace, how do you will 
handle NFS mounted before creating the network namespace ? Do you 
take care of that or simply assume you can't access NFS anymore ?



This is a question that brings up another level of interaction between
networking and the rest of kernel code.
Solution that I use now makes the NFS communication part always run in
the root namespace.  This is discussable, of course, but it's a far more
complicated matter than just device lists or routing :)

if we had containers (not namespaces) then it would be also possible 
to run NFS in context of the appropriate container and thus each user 
could  mount NFS itself with correct networking context.
With a relatively small patch, I was able to make NFS bind to a particular
local IP (poor man's namespace with existing code).  I also changed it so
that multiple mounts to the same destination (and with unique local mount
points) are treated as unique mounts.  This patch was done so that I could
stress test NFS servers, but similar logic might work for namespace isolation
as well...

Ben

-- 
Ben Greear [off-list ref]
Candela Technologies Inc  http://www.candelatech.com
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