Home | About | Sematext search-lucene.com search-hadoop.com
 Search Hadoop and all its subprojects:

Switch to Threaded View
MapReduce >> mail # user >> Fair scheduler.

Copy link to this message
Re: Fair scheduler.

is the bug that Robin is referring to.

Arpit Gupta
Hortonworks Inc.

On Oct 16, 2012, at 3:51 PM, "Goldstone, Robin J." <[EMAIL PROTECTED]> wrote:

> This is similar to issues I ran into with permissions/ownership of
> mapred.system.dir when using the fair scheduler.  We are instructed to set
> the ownership of mapred.system.dir to mapred:hadoop and then when the job
> tracker starts up (running as user mapred) it explicitly sets the
> permissions on this directory to 700.  Meanwhile when I go to run a job as
> a regular user, it is trying to write stuff into mapred.system.dir but it
> can't due to the ownership/permissions that have been established.
> Per discussion with Arpit Gupta, this is a bug with the fair scheduler and
> it appears from your experience that there are similar issues with
> hadoop.tmp.dir.  The whole idea of the fair scheduler is to run jobs under
> the user's identity rather than as user mapred.  This is good from a
> security perspective yet it seems no one bothered to account for this in
> terms of the permissions that need to be set in the various directories to
> enable this.
> Until this is sorted out by the Hadoop developers, I've put my attempts to
> use the fair scheduler on holdŠ
> Regards,
> Robin Goldstone, LLNL
> On 10/16/12 3:32 PM, "Patai Sangbutsarakum" <[EMAIL PROTECTED]>
> wrote:
>> Hi Harsh,
>> Thanks for breaking it down clearly. I would say i am successful 98%
>> from the instruction.
>> The 2% is about hadoop.tmp.dir
>> let's say i have 2 users
>> userA is a user that start hdfs and mapred
>> userB is a regular user
>> if i use default value of  hadoop.tmp.dir
>> /tmp/hadoop-${user.name}
>> I can submit job as usersA but not by usersB
>> ser=userB, access=WRITE, inode="/tmp/hadoop-userA/mapred/staging"
>> :userA:supergroup:drwxr-xr-x
>> i googled around; someone recommended to change hadoop.tmp.dir to
>> /tmp/hadoop.
>> This way it is almost a yay way; the thing is
>> if I submit as userA it will create /tmp/hadoop in local machine which
>> ownership will be userA.userA,
>> and once I tried to submit job from the same machine as userB I will
>> get  "Error creating temp dir in hadoop.tmp.dir /tmp/hadoop due to
>> Permission denied"
>> (as because /tmp/hadoop is own by userA.userA). vise versa if I delete
>> /tmp/hadoop and let the directory be created by userB, userA will not
>> be able to submit job.
>> Which is the right approach i should work with?
>> Please suggest
>> Patai
>> On Mon, Oct 15, 2012 at 3:18 PM, Harsh J <[EMAIL PROTECTED]> wrote:
>>> Hi Patai,
>>> Reply inline.
>>> On Tue, Oct 16, 2012 at 2:57 AM, Patai Sangbutsarakum
>>> <[EMAIL PROTECTED]> wrote:
>>>> Thanks for input,
>>>> I am reading the document; i forget to mention that i am on cdh3u4.
>>> That version should have the support for all of this.
>>>>> If you point your poolname property to mapred.job.queue.name, then you
>>>>> can leverage the Per-Queue ACLs
>>>> Is that mean if i plan to 3 pools of fair scheduler, i have to
>>>> configure 3 queues of capacity scheduler. in order to have each pool
>>>> can leverage Per-Queue ACL of each queue.?
>>> Queues are not hard-tied into CapacityScheduler. You can have generic
>>> queues in MR. And FairScheduler can bind its Pool concept into the
>>> Queue configuration.
>>> All you need to do is the following:
>>> 1. Map FairScheduler pool name to reuse queue names itself:
>>> mapred.fairscheduler.poolnameproperty set to 'mapred.job.queue.name'
>>> 2. Define your required queues:
>>> mapred.job.queues set to "default,foo,bar" for example, for 3 queues:
>>> default, foo and bar.
>>> 3. Define Submit ACLs for each Queue:
>>> mapred.queue.default.acl-submit-job set to "patai,foobar users,adm"
>>> (usernames groupnames)
>>> mapred.queue.foo.acl-submit-job set to "spam eggs"