Re: [PATCH 0/2] namespaces: log namespaces per task
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.
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.
I did originally consider a UUID/GUID for namespaces.
James
- RGB
--
Richard Guy Briggs <rbriggs(a)redhat.com>
Senior Software Engineer, Kernel Security, AMER ENG Base Operating Systems, Red Hat
Remote, Ottawa, Canada
Voice: +1.647.777.2635, Internal: (81) 32635, Alt: +1.613.693.0684x3545