In case it'll eventually be helpful to somebody, here's how I ended up dealing
with this ( run script once a day, distribute over time to avoid overwhelming
file server script pulls data from; )
{
classes:
"do_script" and => { "these_machines", "Hr00_Q1" };
vars:
do_script::
# at: now + randomly over the next hour
"rnd" int => randomint(0,60),
policy => "free";
commands:
do_script::
'/bin/echo "/path/to/script.sh >/tmp/script.log 2>&1" |'
args => "/usr/bin/at now + $(rnd) minutes",
contain => in_shell;
}
On Apr 26, 2011, at 4:38 AM, Francoeur, Louis wrote:
> If you don't want the messages about redefinition of constant,
> You have to add:
> policy => "free"
> to your variable.
>
> Example:
> "jobs_in_queue" string => execresult("/usr/bin/lpstat -o -i |
> /usr/bin/grep \"^$(queue)-\" | /usr/bin/wc -l", "useshell"),
> policy => "free";
>
> Louis Francoeur
> Unix administrator/Adminstrateur Unix
>
> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]] On Behalf Of Jesse Becker
> Sent: Monday, April 25, 2011 10:16 PM
> To: Michael Stevens
> Cc: help-cfengine
> Subject: Re: Avoiding "Duplicate selection of value"
>
> On Mon, Apr 25, 2011 at 08:21:21PM -0400, Michael Stevens wrote:
>> Is there a preferred method for getting variables using randomint() to stop
>> getting defined once they're set, eg, avoid this;
>>
>> !! Redefinition of a constant scalar "rnd" (was 2786 now 195)
>> !! Redefinition of a constant scalar "rnd" (was 195 now 2749)
>> !! Redefinition of a constant scalar "rnd" (was 2749 now 1852)
>>
>>
>> I'm trying to set a randomized 0/60 minute delay on a command that runs
>> once a day so that all the machines don't fire right at the same time and
>> overload a file server the command tells them to grab a bunch of files from.
>> If there's a better way to do this than embedding an "at" or "sleep" in my
>> command, let me know ...
>
> This isn't a direct answer to your question, but I had to do something
> similar. I wanted the clients to consistantly choose a host from a
> list (it happens to be a list of two hosts, but the idea should scale).
>
> I used something like this (untested, use at own risk, formatting
> adjusted for clarity in email):
>
> bundle agent foo {
>
> vars:
> hostname_hash string => hash(getenv("HOSTNAME","40"),'md5');
> servername string => execresult(
> "/bin/echo
> ${hostname_hash} |
> /bin/cut -c -16 |
> perl -e perl
> statement could'll=qw(hostA hostB);'
> -e
> '$L=scalar @l;'
> -e 'print $l[hex(<>)%$L];'
> "useshell");
> }
>
> I actually think this a bit better than a purely random number that
> changes each time. This should give you a "random", but consistant
> value for each hostname.
>
> In your case, you just want a number 0-60, so the execresult command
> could be replaced with something like:
>
> /bin/echo ${hostname_hash} |
> /bin/cut -c -16 |
> perl -e 'print <>%61;'"
>
>
> Note that I've clipped only 16 characters, instead of the full 32 that
> come from md5sum, in order to avoid integer overflows in Perl.
>
>
> --
> Jesse Becker
> NHGRI Linux support (Digicon Contractor)
> _______________________________________________
> Help-cfengine mailing list
> [email protected]
> https://cfengine.org/mailman/listinfo/help-cfengine
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