Re: The issues for agreeing on a virtualization/namespaces implementation.

[ebiederm@xmission.com (Eric W. Biederman)]

Kirill Korotaev <dev@sw.ru> writes:

>>>Eric W. Biederman wrote:
>>>So it seems the clone( flags ) is a reasonable approach to create new
>>>namespaces. Question is what is the initial state of each namespace?
>>>In pidspace we know we should be creating an empty pidmap !
>>>In network, someone suggested creating a loopback device
>>>In uts, create "localhost"
>>>Are there examples where we rather inherit ?  Filesystem ?
>> Of course filesystem is already implemented, and does inheret a full
>> copy.
>
> why do we want to use clone()? Just because of its name and flags?
> I think it is really strange to fork() to create network context. What has
> process creation has to do with it?

Agreed.  Although clones brother unshare takes process creation out of the
picture, but otherwise preserves the same interface.

> After all these clone()'s are called, some management actions from host system
> are still required, to add these IPs/routings/etc.
> So? Why mess it up? Why not create a separate clean interface for container
> management?

If we need additional arguments besides create the thing.  We have a clear
argument that clone is completely the wrong interface.

However.  So far I have not seen an instance where using the existing
standard configuration mechanisms from inside the namespace is not the
proper way to set things up.  The only thing I know that needs to happen from
outside is to pass the container a network interface.  And if it is a physical
interface that is all that must happen.

Eric
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