Re: [RFC] How to handle the rules engine for cgroups

[Paul Menage]

On Thu, Jul 3, 2008 at 8:54 AM, Vivek Goyal <vgoyal@xxxxxxxxxx> wrote:
>
> As of today it should happen because newly execed process will run into
> same cgroup as parent.  But that's what probably we need to avoid.
> For example, if an admin has created three cgroups "database", "browser"
> "others" and a user launches "firefox" from shell (assuming shell is running
> originally in "others" cgroup), then any memory allocation for firefox should
> come from "browser" cgroup and not from "others".

I think that I'm a little skeptical that anyone would ever want to do that.

Wouldn't it be a simpler mechanism for the admin to simply have
wrappers around the "firefox" and "oracle" binaries that move the
process into the "browser" or "database" cgroup before running the
real binaries?

>
> I am assuming that this will be a requirement for enterprise class
> systems. Would be good to know the experiences of people who are already
> doing some kind of work load management.

I can help there. :-) At Google we have two approaches:

- grid jobs, which are moved into the appropriate cgroup (actually,
currently cpuset) by the grid daemon when it starts the job

- ssh logins, which are moved into the appropriate cpuset by a
forced-command script specified in the sshd config.

I don't see the rule-based approach being all that useful for our needs.

It's all very well coming up with theoretical cases that a fancy new
mechanism solves. But it carries more weight if someone can stand up
and say "Yes, I want to use this on my real cluster of machines". (Or
even "Yes, if this is implemented I *will* use it on my desktop" would
be a start)

Paul
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