Thanks for your response. See comments below.
Regards, Per Steffensen
Alejandro Abdelnur skrev:
[moving common-user@ to BCC]
Oozie is not HA yet. But it would be relatively easy to make it. It was
designed with that in mind, we even did a prototype.
Ok, so if it isnt HA out-of-the-box I believe Oozie is too big a
framework for my needs - I dont need all this workflow stuff - just a
plain simple job trigger that triggers every 5th minute. I guess I will
try out something smaller like Quartz Scheduler. It also only have
HA/cluster support through JDBC (JobStore) but I guess I could fairly
easy make a HDFSFilesJobStore which still hold the properties so that
Quartz clustering works.
But what I would really like to have is a scheduling framework that is
HA out-of-the-box. Guess Oozie is not the solution for me. Anyone knows
about other frameworks?
Oozie consists of 2 services, a SQL database to store the Oozie jobs state
and a servlet container where Oozie app proper runs.
The solution for HA for the database, well, it is left to the database. This
means, you'll have to get an HA DB.
I would really like to avoid having to run a relational database.
Couldnt I just do the persistence of Oozie jobs state in files on HDFS?
The solution for HA for the Oozie app is deploying the servlet container
with the Oozie app in more than one box (2 or 3); and front them by a HTTP
load-balancer.
The missing part is that the current Oozie lock-service is currently an
in-memory implementation. This should be replaced with a Zookeeper
implementation. Zookeeper could run externally or internally in all Oozie
servers. This is what was prototyped long ago.
Yes but if I have to do ZooKeeper stuff I could just do the scheduler
myself and make run no all/many boxes. The only hard part about it is
the "locking" thing that makes sure only one job-triggering happens in
the entire cluster when only one job-triggering is supposed to happen,
and that the job-triggering happens no matter how many machines might be
down.
Thanks.
Alejandro
On Thu, Sep 1, 2011 at 4:14 AM, Ronen Itkin <[email protected]> wrote:
If I get you right you are asking about Installing Oozie as Distributed
and/or HA cluster?!
In that case I am not familiar with an out of the box solution by Oozie.
But, I think you can made up a solution of your own, for example:
Installing Oozie on two servers on the same partition which will be
synchronized by DRBD.
You can trigger a "failover" using linux Heartbeat and that way maintain a
virtual IP.
On Thu, Sep 1, 2011 at 1:59 PM, Per Steffensen <[email protected]>
wrote:
Hi
Thanks a lot for pointing me to Oozie. I have looked a little bit into
Oozie and it seems like the "component" triggering jobs is called
"Coordinator Application". But I really see nowhere that this Coordinator
Application doesnt just run on a single machine, and that it will
therefore
not trigger anything if this machine is down. Can you confirm that the
"Coordinator Application"-role is distributed in a distribued Oozie
setup,
so that jobs gets triggered even if one or two machines are down?
Regards, Per Steffensen
Ronen Itkin skrev:
Hi
Try to use Oozie for job coordination and work flows.
On Thu, Sep 1, 2011 at 12:30 PM, Per Steffensen <[email protected]>
wrote:
Hi
I use hadoop for a MapReduce job in my system. I would like to have the
job
run very 5th minute. Are there any "distributed" timer job stuff in
hadoop?
Of course I could setup a timer in an external timer framework (CRON or
something like that) that invokes the MapReduce job. But CRON is only
running on one particular machine, so if that machine goes down my job
will
not be triggered. Then I could setup the timer on all or many machines,
but
I would not like the job to be run in more than one instance every 5th
minute, so then the timer jobs would need to coordinate who is actually
starting the job "this time" and all the rest would just have to do
nothing.
Guess I could come up with a solution to that - e.g. writing some
"lock"
stuff using HDFS files or by using ZooKeeper. But I would really like
if
someone had already solved the problem, and provided some kind of a
"distributed timer framework" running in a "cluster", so that I could
just
register a timer job with the cluster, and then be sure that it is
invoked
every 5th minute, no matter if one or two particular machines in the
cluster
is down.
Any suggestions are very welcome.
Regards, Per Steffensen
--
*
Ronen Itkin*
Taykey | www.taykey.com
