web-tracker question

[Keith Wiley <kw...@keithwiley.com>]

I'm curious about the relationship between the namenode/job/task trackers and the machine's web server?  Do the former require the latter?  Does successful connection to the trackers imply that the machine has a web server up and running?  I realize the ports are totally different (web is generally port 80), but the trackers are headed with the "http" URI, so I'm a little unsure if that means anything w.r.t. my question.  Can you run and access the trackers on a machine that doesn't have a webserver installed or running?

I know, it's a weird question.  Thanks for any quick response.

Thanks.

________________________________________________________________________________
Keith Wiley     kwiley@keithwiley.com     keithwiley.com    music.keithwiley.com

"The easy confidence with which I know another man's religion is folly teaches
me to suspect that my own is also."
                                           --  Mark Twain
________________________________________________________________________________

Re: web-tracker question

[Keith Wiley <kw...@keithwiley.com>]

I don't like to clutter up with list with simple "thanks" responses...so, thanks.

Cheers!

________________________________________________________________________________
Keith Wiley     kwiley@keithwiley.com     keithwiley.com    music.keithwiley.com

"I used to be with it, but then they changed what it was.  Now, what I'm with
isn't it, and what's it seems weird and scary to me."
                                           --  Abe (Grandpa) Simpson
________________________________________________________________________________

Re: web-tracker question

[Al Thompson <at...@ngmoco.com>]

Hi Keith:

On Fri, Jul 20, 2012 at 3:28 PM, Keith Wiley <kw...@keithwiley.com> wrote:

> I'm curious about the relationship between the namenode/job/task trackers
> and the machine's web server?  Do the former require the latter?


The hadoop daemons embed a jetty instance to serve their user interfaces
over http.
You will see the jetty instance come online in your logs with lines like
this:

2012-07-20 22:55:14,519 INFO org.apache.hadoop.http.HttpServer: Port
returned by webServer.getConnectors()[0].getLocalPort() before open() is
-1. Opening the listener on 50060
2012-07-20 22:55:14,519 INFO org.apache.hadoop.http.HttpServer:
listener.getLocalPort() returned 50060
webServer.getConnectors()[0].getLocalPort() before open() is -1. Opening
the listener on 50060
2012-07-20 22:55:14,519 INFO org.apache.hadoop.http.HttpServer:
listener.getLocalPort() returned 50060
webServer.getConnectors()[0].getLocalPort() returned 50060
2012-07-20 22:55:14,519 INFO org.apache.hadoop.http.HttpServer: Jetty bound
to port 50060

Does successful connection to the trackers imply that the machine has a web
> server up and running?


A tasktracker that is "up" should have it's web interface served by it's
embedded jetty instance.


> I realize the ports are totally different (web is generally port 80), but
> the trackers are headed with the "http" URI, so I'm a little unsure if that
> means anything w.r.t. my question.  Can you run and access the trackers on
> a machine that doesn't have a webserver installed or running?
>
>
The hadoop daemons do not require a web server to be running on any grid
nodes.


> I know, it's a weird question.  Thanks for any quick response.
>
>
HTH

Regards,
Al