Re: [PATCH v4 3/3] Make core_pattern support namespace

[Krister Johansen <kjlx@templeofstupid.com>]

On Tue, Oct 25, 2016 at 03:28:56PM +0800, Cao Shufeng wrote:
> From: Zhao Lei <zhaolei@cn.fujitsu.com>
> It will bring us following benefit:
> 1: Each container can change their own coredump setting
>    based on operation on /proc/sys/kernel/core_pattern
> 2: Coredump setting changed in host will not affect
>    running containers.
> 3: Support both case of "putting coredump in guest" and
>    "putting curedump in host".

Would you explain more about case #3 here?  In particular, I'm curious
what the impact is for systems that have already configured core_pattern
with the understanding that the program might be invoked to handle
either a host or a container core.  In particular, is there any way to
specify that the container handler fall back to the host handler?

On the systems that I've configured, /proc/sys is mounted read-only in the
container.  The host has a special program run from core_pattern that
determines which container generated the core.  It then stores the cores
in a directory that uniquely identifies the container.  The cores are
isolated on their own filesystem, and given a quota per-container.  The
eventual goal is to have a service evacuate the cores to an object store
where we can make them available to the customer via a web service.

Does your change still allow a global handler in the host to process
cores from containers?  Or is that behavior removed completely?

-K