containers development plans

Serge E. Hallyn serge at
Mon Jul 9 08:25:58 PDT 2007

Quoting Paul Jackson (pj at
> Thanks for responding, Eric.
> For those like me (I suspect I'm not alone) who drift in and out of
> this discussion, perhaps this would be a good time to describe again
> what are the containers you're discussing here - their key purpose(s)
> and their essential architecture.
> For extra credit, putting aside the conflicting use of the word
> 'container', how would, in your view, PMC's (Paul Menage's Containers)
> relate to TTC's (This Thread's Containers)?  Would either use the other?

Again, we want to discuss both in this roadmap.

Let's stick to talking about PMCs and namespaces (TTC's).

The namespace work just aims to take any resources which userspace might
wish to identify by a global id, and allow a process to unshare it's
view of that namespace so that

	1. it can isolate its resources from those of other processes
	   (virtual servers)
	2. it can guarantee that certain ids are available, to make
	   process restart possible.

PMCs are very useful to both process restart and virtual servers:

	1. for resource management
	2. for providing APIs for namespace operations
	   a. for example, the freezer subsystem Cedric recently
	      sent out, which can be used to freeze a checkpoint/restart
	      job or virtual server (or any type of container) to allow
	      safe checkpoint.
	   b. to restrict a virtual server's cpu and memory usage

> Are they complimentary, conflicting, ...?

Very much complimentary.


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