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

Switch to Threaded View
HBase, mail # dev - Can master initialization be done after postStartMaster is called?


Copy link to this message
-
Re: Can master initialization be done after postStartMaster is called?
Gary Helmling 2012-03-19, 17:30
Hi Ram,

The MasterObserver.postStartMaster() hook was added after we ran into
a case where we wanted a single initialization point as soon as the
active master was up for security implementation.  In AccessController
we use it to create the "_acl_" table if it doesn't exist.  So in this
case it made sense to wait until the active master was fully up.

This is admittedly a pretty specific case, so it may be worth
rethinking some things as we generalize it.  If you're looking to have
a coprocessor perform some setup work required _before_ the active
master is available, maybe we should also look at adding a
MasterObserver.preStartMaster() hook?

Can you describe more how you're looking at applying this so we can
all understand the interactions?

--gh

On Mon, Mar 19, 2012 at 6:05 AM, Ramkrishna.S.Vasudevan
<[EMAIL PROTECTED]> wrote:
> Hi devs
>
>
>
> Currently we set HMaster initialized=true before calling postStartMaster.
>
> But if thro coprocessor we add some more code for some additional
> initialization or some cleanup work the master gets initialized even before
> that?
>
>
>
> Can we initialize the master after postStartMaster?  If it is ok I can file
> a JIRA for the same?
>
>
>
> Regards
>
> Ram
>