[RFC] Container mini-summit agenda for Sept 3, 2007
Cedric Le Goater
clg at fr.ibm.com
Fri Aug 31 07:26:02 PDT 2007
Oren Laadan wrote:
> Cedric Le Goater wrote:
>> Hello All,
>> Some of us will meet next week for the first mini-summit on containers.
>> Many thanks to Alasdair Kergon and LCE for the help they provided in
>> making this mini-summit happen !
>> It will be help on Monday the 3rd of September from 9:00 to 12:45 at LCE
>> in room D. We also might get a phone line for external participants and,
>> if not, we should be able to set up a skype phone.
>> Here's a first try for the Agenda.
>> Global items
>> [ let's try to defer discussion after presentation ]
>> * Pavel Emelianov status update
>> * Serge E. Hallyn Container Roadmap including
>> . task containers (Paul Menage)
>> . resource management (Srivatsa Vaddagiri)
>> Special items
>> [ brainstorm sessions which we would like to focus on ]
>> * builing the global container object ('a la' openvz or vserver)
>> * container user space tools
>> * container checkpoint/restart
> 5. checkpoint/restart
> memory c/r
> (there are a few designs and prototypes)
> (though this may be ironed out by then)
> per-container swapfile?
> overall checkpoint strategy (one of:)
> overall restart strategy
> use freezer API
> use suspend-to-disk?
> "set identifier" syscall
> pid namespace
> There are other identifiers - pseudo terminals, message queues (mq)
right, we have plans for developing these if needed (cf 2.)
> (if you insist on supporting these ...). In general, we need a way
> to specify the virtual id of a resource that is created.
right, pierre peiffer has sent such a pachset for the sysvipc namespace.
I'm looking at a clone_with_pid() for pid namespace.
> I suggest
> that this should be part of an interface between c/r and containers
> (see below)
> live migration
> aka pre-copy (which can be used for live migration but also to reduce
> the downtime due to a checkpoint).
yes that's usually what the buzz term "live migration" is used for.
> how about adding incremental checkpoint to the list ?
sure. I think it's a bit early to address these topic but we should have
them in mind as some implementations already exist. And we need to gather
all the needs.
> I think that it is also important to discuss an interface between c/r and
> containers, each of which stands on it own. For instance, how to request
> a specific virtual id (during restart), define required notifiers (to
> set/unset c/r related data on/off a task), control c/r-related setting of
> container (e.g. frozen, restarting) that may affect behavior, such as
> signal handling, and so forth.
This is exactly what we want to talk about.
We need to identify these C/R needs, talk and agree about possible APIS
and then convince the linux subsystem maintainers that they are useful
for a large set of C/R solutions based on containers.
> Also, such an interface can allow existing c/r implementations to work with
> different virtualization implementations as they become available.
what you call "virtualization" (private identifier namespaces), is I think
being covered by the namespaces. These namespaces are not complete (like
we're missing a way to reassign ids) but they are going in the right
direction, IMO. However, I don't think there will be different
"virtualization" implementations in mainline.
> Many of these were discussed in a recent Zap paper present in USENIX:
> The paper describes important design choices in Zap (but I'm biased ...).
> I think it may serve as an appetizer for the discussion :P
Thanks, I hope we all have time to read it.
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