Re: [vserver] Guest hourly/daily/... cron job parallel execution

From: Corey Wright <>
Date: Thu 17 Jan 2013 - 16:36:08 GMT
Message-Id: <>

On Thu, 17 Jan 2013 08:43:21 +0000
Fiedler Roman <> wrote:

> Hello List,
> What would be the most suitable solution to avoid high load/overlong cron job execution for hourly/daily/... jobs? When using similar vservers, all of them would start those jobs at the same time.

depends (imho):

providing/using a hosting service and want guarantees? cgroup blkio
cooperative administration of vservers? nice and/or ionice.
"poor man's" approach? ${RANDOM}.

i haven't tested/used the cgroup's blkio controller, but in theory that's
what it's suppose to do (cgroup's other controllers work for me).

> Currently I'm using a script on the host to run no more than N guest hourly/daily/... jobs in parallel.

i presume you are administering them on your own and/or somebody else's
behalf and can schedule them cooperatively. i wouldn't expect this level of
cooperation from/among users of a hosting service (ie system administration
by committee).

i do cooperative scheduling of some jobs and do it sequentially on each
vserver from the host, but that's because i'm the only administrator/user of
my vservers and host them myself (and it's simple/stupid).

if i was using a vserver provided by someone else (eg hosting service), then
i would either expect them to provide guaranteed io throughput (just like for
cpu and memory) or i'd randomize it myself (based on how much i was paying;
poor man's solution).

i've already seen randomizing as a solution to not overloading resources
among controlled but uncoordinated systems: system/virus updates are randomly
staggered on corporate desktops so as to not overload the server and/or
congest the network.


> Is that a good solution to the problem?
> If not, what would be better?
> If yes, add the script to vserver-utils? Apart from that, the current approach allows the host to detect, when all guest dailies have completed, so that it can start actions that need to be run after all those e.g. guest backup-prepare before backup start on host.
> Roman
Received on Thu Jan 17 16:36:19 2013
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