Re: [PATCH 0/2] namespaces: log namespaces per task
Quoting Richard Guy Briggs (rgb(a)redhat.com):
On 14/05/03, James Bottomley wrote:
> On Tue, 2014-04-22 at 14:12 -0400, Richard Guy Briggs wrote:
> > Questions:
> > Is there a way to link serial numbers of namespaces involved in migration of a
> > container to another kernel? (I had a brief look at CRIU.) Is there a unique
> > identifier for each running instance of a kernel? Or at least some identifier
> > within the container migration realm?
>
> Are you asking for a way of distinguishing an migrated container from an
> unmigrated one? The answer is pretty much "no" because the job of
> migration is to restore to the same state as much as possible.
I hadn't thought to distinguish a migrated container from an unmigrated
one, but rather I'm more interested in the underlying namespaces. The
use of a generation number to identify a migrated namespace may be
useful along with the logging to tie them together.
> Reading between the lines, I think your goal is to correlate audit
> information across a container migration, right? Ideally the management
> system should be able to cough up an audit trail for a container
> wherever it's running and however many times it's been migrated?
The original intent was to track the underlying namespaces themselves.
This sounds like another layer on top of that which sounds useful but
that I had not yet considered.
But yes, that sounds like a good eventual goal.
Right and we don't need that now, all *I* wanted to convince myself of
was that a serial # as you were using it was not going to be a roadlbock
to that, since once we introduce a serial #, we're stuck with that as
user-space facing api.
> In that case, I think your idea of a numeric serial number in a
dense
> range is wrong. Because the range is dense you're obviously never going
> to be able to use the same serial number across a migration. However,
> if you look at all the management systems for containers, they all have
> a concept of some unique ID per container, be it name, UUID or even
> GUID. I suspect it's that you should be using to tag the audit trail
> with.
That does sound potentially useful but for the fact that several
containers could share one or more types of namespaces.
Would logging just a container ID be sufficient for audit purposes? I'm
going to have to dig a bit to understand that one because I was unaware
each container had a unique ID.
They don't :)
I did originally consider a UUID/GUID for namespaces.
So I think that apart from resending to address the serial # overflow
comment, I'm happy to ack the patches. Then we probably need to convicne
Eric that we're not torturing kittens.
-serge