After some testing, the fix is to change the '>=' comparison to just '>', so
that the sum of normal reservations and block reservations can equal the max
concurrent limit for an image. So line 3895 (your number may vary as I've added
in some other mod code) in utils.php should look like:
if(($usagecnt + $row['currentusage'] - $decforedit) >
$images[$imageid]['maxconcurrent']) {
It's near the end of the isAvailable function.
Mike
From: Waldron, Michael H
Sent: Thursday, February 06, 2014 3:05 PM
To: '[email protected]'
Subject: RE: Block allocation problem
I think I may have traced it to this section of code in utils.php, in the
'isAvailable' function where It checks the max concurrent usage. If I'm
following the logic correctly (BIG if), the equation near the end of the
function around line 3895 is the kicker.
if(($usagecnt + $row['currentusage'] - $decforedit) >=
$images[$imageid]['maxconcurrent']) {
semUnlock();
return -1;
In my case, $usagecnt is 0 (no current reservations), $decforedit is 0,
currentusage is 4 (block computers with the image and not already used), and
maxconcurrent is 4. So the statement resolves to 0+4-0 >= 4. Thus it returns -1
saying that max concurrent usage has been reached, even with none of the
sessions in use.
Mike
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Subject: Re: Block allocation problem permalink
From: Dmitri Chebotarov ([email protected])
Date: Feb 6, 2014 11:42:50 am
List: org.apache.incubator.vcl-dev
What a coincidence! :) Just ran into exactly the same issue last night. Have 16
max computers and 16 in block allocations - users in the right group cannot
make reservation.
-- Thank you,
Dmitri Chebotarov VCL Sys Eng, Engineering & Architectural Support, TSD - Ent
Servers & Messaging 223 Aquia Building, Ffx, MSN: 1B5 Phone: (703) 993-6175 |
Fax: (703) 993-3404
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On 2/6/14, 13:38 , "Waldron, Michael H" <[email protected]> wrote:
We had a block allocation for an image that is limited to 4 concurrent
sessions. When the allocation time arrived, users who were in the user group
for the allocation trying to make a reservation received a message stating that
the environment is limited in the number of concurrent sessions, and that no
further reservations could be made during this time. There were NO active
reservations for the image at the time.
By increasing the concurrent limit on the image, these users were then able to
make a reservation. I verified that the users were indeed in the user group. It
was if it wasn't honoring their group membership for the allocation, although
when I increased the limit and they successfully made a reservation, I could
see that they were getting the reserved machines.
Why wouldn't it allow any reservations for a block allocation that matched the
concurrent use limit??
Mike Waldron Systems Specialist ITS - Research Computing Center University of
North Carolina at Chapel Hill
