Rq-2.3.2


#1

NAME
rq v2.3.2

SYNOPSIS
rq (queue | export RQ_Q=q) mode [mode_args]* [options]*

URIS

http://raa.ruby-lang.org/project/rq/
http://codeforpeople.com/lib/ruby/rq/rq-2.3.2/README
http://www.linuxjournal.com/article/7922

DESCRIPTION
ruby queue (rq) is a zero-admin zero-configuration tool used to
create
instant linux clusters. rq requires only a central nfs filesystem in
order
to manage a simple sqlite database as a distributed priority work
queue.
this simple design allows researchers to install and configure, in
only a
few minutes and without root privileges, a robust linux cluster
capable of
distributing processes to many nodes - bringing dozens of powerful
cpus to
their knees with a single blow. clearly this software should be kept
out of
the hands of free radicals, seti enthusiasts, and one mr. j safran.

the central concept of rq is that n nodes work in isolation to pull
jobs
from an centrally mounted nfs priority work queue in a synchronized
fashion.
the nodes have absolutely no knowledge of each other and all
communication
is done via the queue meaning that, so long as the queue is available
via
nfs and a single node is running jobs from it, the system will
continue to
process jobs. there is no centralized process whatsoever - all nodes
work
to take jobs from the queue and run them as fast as possible. this
creates
a system which load balances automatically and is robust in face of
node
failures.

although the rq system is simple in it’s design it features powerful
functionality such as priority management, predicate and sql query ,
compact
streaming command-line processing, programmable api, hot-backup, and
input/capture of the stdin/stdout/stderr io streams of remote jobs.
to date
rq has had no reported runtime failures and is in operation at dozens
of
research centers around the world.

enjoy.

-a


#2

I couldn’t find the changes list. What is new in this version?

Guillaume.

Le 28 avr. 06, à 17:36, Ara.T.Howard a écrit :


#3

On Sat, 29 Apr 2006, Guillaume M. wrote:

I couldn’t find the changes list. What is new in this version?

Guillaume.

sorry. here you go

http://www.codeforpeople.com/lib/ruby/rq/rq-2.3.2/HISTORY


2.3.2:
- added ‘rq q io’ command
- streamlined ‘rq q status’ output considerably
- fixed few small bugs in util.rb
- patched yaml inline behaviour for syck in 1.8.4. backward
compatible with
older ruby versions - at least through 1.8.2.
- changed naming scheme for rotation and added automatic attempt to
compress
the rotation
- made shutdown via ctrl-c when running from commandline (as
opposed to
daemon) quieter
- fixed a few bad exit codes, for example creating a queue exited
with
$?==1, it is now correctly 0
- added support for job stdin to be provided and stdout/stderr
captured.
for instance

     rq queue submit cat --stdin=input_for_cat.txt

     cat input_for_cat.txt | rq queue submit cat --stdin=-

     rq queue submit cat --stdin=- < input_for_cat.txt

   stdout and stderr are stored in the queue directory in a file 

named by
jid.
- changed behaviour of reading jobs from stdin: IMPORTANT :
it’s now
REQUIRED to provide a ‘-’ as the argument for any command
that should
read from stdin. for instance one would use

     rq queue submit - < joblist
   or
     jobgenerator.rb | rq queue submit -

   vs the old

     rq queue submit < joblist
   or
     jobgenerator.rb | rq queue submit


   the distiction was added to make running submissions from 

scripts/cron
(where STDIN.tty? == false) easier and providing the job stdinput
on stdin
possible.
- added a restart mode to restart a feeder : rq q restart
- modes shutdown, stop, and restart now return a non-zero exit code
if they
fail to signal the feeder, zero otherwise
- fixed bug with restart mode whereby re-exec failed due to falsely
thinking
pid was locked (it is - but only by the current process!)
- added default bin dir underneath q dir. this dir is added to the
path
before excuting commands to it’s an easy place to put things
where they’ll
be found

the biggest change is the ability to provide jobs stdin at submit time
and to
capture their stdout/stderr. for instance you can now do this

rq q submit cat --stdin=/etc/passwd

or

find | grep *geo.tif | rq q submit geolocate.rb --stdin=-

to submit jobs that take stdin. the stdin is squirled away in the q
dir.
later, when the job is run, the stdout and stderr are captured in the
same
way. so, in the above example, if the submitted job had jid=42 you’d
have

q/stdin/42 # the stdin provided

before the job was run and

q/stdin/42
q/stdout/42
q/stderr/42

once the job was set running. this is extrememly cool since you can do

tail -F q/stderr/42

to monitor a process on a remote node.

cheers.

-a