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From Chris Douglas <cdoug...@apache.org>
Subject Re: "Reservation" ambiguity
Date Wed, 05 Aug 2015 01:48:45 GMT
How visible are (1) reservations? They're an internal, implementation
detail exposed in metrics only to explain the edge cases they create.
Are users typically aware of them?

SLA reservations (2) are user-visible, and express the contract with
users/operators symmetrically. While (1) is a concept, renaming (2)
would require user-breaking code changes.

Unless you're discussing the intersection- the effect of reservations
(1) on a reservation (2)- it's usually clear from context... I'd
rather avoid breaking anyone listening to the metrics in Hadoop-3.

Maybe reservations (2) could have been named "sessions", but that
collided with applications that already used it for a similar concept.

On Wed, Jul 29, 2015 at 10:37 AM, Karthik Kambatla <kasha@cloudera.com> wrote:
> Hi folks
> We use the word "reservation" to mean both (1) reservations on nodes to
> avoid starvation of big container asks, and (2) the recent SLA work. This
> is confusing both to developers and end-users.
> I was wondering if people are open to calling the first one a "hold" and
> the second one a "reservation". We can change the terminology in the code
> and add new metrics for hold in branch-2 and remove the metrics for
> reserved* in Hadoop-3?
> Thoughts?

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