containers development plans

Serge E. Hallyn serue at
Mon Jul 2 14:53:15 PDT 2007

Quoting Erich Focht (efocht at
> Hi,
> On Monday 02 July 2007 18:55, Serge E. Hallyn wrote:
> > A list of the people we are currently aware of who are showing interest
> > in these features follows.  What I'd like to know is, from this list, do
> > some people know what general or specific areas they plan to or want to
> > work on over the next year?
> > 
> > Stakeholders:
> > 	Eric Biederman
> > 	google
> > 	ibm
> > 	kerlabs
> > 	openvz
> > 	osdl (Masahiko Takahashi?)
> > 	vserver
> > 
> > Who is missing from the list?
> you could add the XtreemOS project to the list. It's grid project and we
> need to use containers for grid job isolation. We're currently using BLCR
> for checkpointing, and also kerrighed, but aim at switching to containers
> and will work on container checkpointing. XtreemOS is related to
> kerlabs & kerrighed, but has broader interests in containers.

That's cool.  I'll go read up on XtreemOS before I ask stupid

> > What more needs to be added to this list?
> By the way, there are potential synergies between container checkpointing
> work and the need of the VM to have something like per cpuset of per
> container swap (as explained in the VM BoFS at OLS, there are unnecessary
> OOMs with a common swap).   

Ah, cool, I hadn't heard that.  At the risk of really exploding the # of
container subsystems needed to be composed in order to do
checkpoint/restart, this does sound like a separate container subsystem
which just attaches a swapfile to it's tasks might then be a useful
thing.  It can then be composed with a cpuset or a freezer subsystem, or
both (at the same time - separately might be weird :).

I guess then for checkpoint we just freeze the subsystem, force a write
of all dirty pages using something like Dave's patch, somehow create a
copy-on-write clone as the checkpoint, then unfreeze.  (and oh yeah,
checkpoint all the other crap too  :)

> Regards,
> Erich


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