RM internal services starting during init()

[Karthik Kambatla <ka...@cloudera.com>]

Hi yarn-devs,

I ran into this during my work on RM HA - YARN-149 and co - and would
greatly appreciate any suggestions on how to go about this.

The basic idea is to have an Active/Standby architecture the same way as in
HDFS. My approach is to init() both RMs the same way. The RMs are to behave
differently in start() - we start all services on the Active RM and only
those we want to on the Standby.

However, post-init, some of the services are already starting, at least
they start listening on their respective ports. Examples are the scheduler,
resource tracker service etc.

Is there a particular reason this is being done in init(). If not, it would
be nice to move the code responsible for starting these services to
serviceStart().

Thoughts?

Many thanks,
Karthik

Re: RM internal services starting during init()

[Jian He <jh...@hortonworks.com>]

+1 for this, init() should only do all the initialization work(initializing
variables etc. ), and following starting behavior works should be performed
in start(),
 unless we have a specific reason to put those methods in init().

Jian


On Sat, Aug 17, 2013 at 4:03 PM, Karthik Kambatla <ka...@cloudera.com>wrote:

> Hi yarn-devs,
>
> I ran into this during my work on RM HA - YARN-149 and co - and would
> greatly appreciate any suggestions on how to go about this.
>
> The basic idea is to have an Active/Standby architecture the same way as in
> HDFS. My approach is to init() both RMs the same way. The RMs are to behave
> differently in start() - we start all services on the Active RM and only
> those we want to on the Standby.
>
> However, post-init, some of the services are already starting, at least
> they start listening on their respective ports. Examples are the scheduler,
> resource tracker service etc.
>
> Is there a particular reason this is being done in init(). If not, it would
> be nice to move the code responsible for starting these services to
> serviceStart().
>
> Thoughts?
>
> Many thanks,
> Karthik
>

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