Re: [RFC][PATCH 0/9] Make containers kernel objects

From: Eric W. Biederman
Date: Tue May 23 2017 - 11:24:17 EST


David Howells <dhowells@xxxxxxxxxx> writes:

> Eric W. Biederman <ebiederm@xxxxxxxxxxxx> wrote:
>
>> > As an example, I could set up a client machine with two ethernet ports,
>> > set up two DNS+NFS servers, each of which think they're called "foo.bar"
>> > and attach each server to a different port on the client machine. Then I
>> > could create a pair of containers on the client machine and route the
>> > network in each container to a different port. Now there's a problem
>> > because the names of the cached DNS records for each port overlap.
>>
>> Please look at ip netns add.
>
> warthog>man ip | grep setns
> warthog1>

Not setns netns


>> It does solve this in userspace rather simply.
>
> Ummm... How? The kernel DNS resolver is not namespace aware.

But it works fine if called in the proper context and we have a defacto
standard for where to put all of the files (the tricky part) if you are
dealing with multiple network namespaces simultaneously.

Eric