Hi Thommy,
{quote}
Because I don't see how this is ever going to work in scenarios where the
AM is on a different node than the containers.
{quote}
-- I do not quite understand this part. AM essentially is running in a
container as well. And the http server is brought up in the same container.
{quote}
even if we can't get a better address for the AM from YARN, we could at
least filter the addresses we get back from the JVM to exclude loopbacks.
{quote}
-- You are right. InetAddress.getLocalHost() gives back loopback address
sometimes. We should filter this out. Just googling one possible solution
<http://www.coderanch.com/t/491883/java/java/IP> .
+ @Yi, @Navina,
Also, I think this fix should go to the 0.10.0 release.
What do you guys think?
Thanks,
Fang, Yan
yanfang...@gmail.com
On Thu, Jul 30, 2015 at 6:39 PM, Yan Fang <yanfang...@gmail.com> wrote:
> Just one point to add:
>
> {quote}
> AM gets notified of container status from the RM.
> {quote}
>
> I think this is not 100% correct. AM can communicate with NM through
> NMClientAsync
> <https://hadoop.apache.org/docs/r2.7.1/api/org/apache/hadoop/yarn/client/api/async/NMClientAsync.html>
> to
> get container status, though Samza does not implement the CallbackHandler.
>
> Thanks,
>
> Fang, Yan
> yanfang...@gmail.com
>
> On Thu, Jul 30, 2015 at 6:06 PM, Navina Ramesh <
> nram...@linkedin.com.invalid> wrote:
>
>> The NM (and hence, by extension the container) heartbeats to the RM, not
>> the AM. AM gets notified of container status from the RM.
>> The AM starts / stops /releases a container process by communicating to
>> the
>> NM.
>>
>> Navina
>>
>>
>> On Thu, Jul 30, 2015 at 5:55 PM, Thomas Becker <tobec...@tivo.com> wrote:
>>
>> > Ok, I thought there was some communication from the container to the AM,
>> > it sounds like you're saying it's in the other direction only? Don't
>> > containers heartbeat to the AM? Regardless, even if we can't get a
>> better
>> > address for the AM from YARN, we could at least filter the addresses we
>> get
>> > back from the JVM to exclude loopbacks.
>> >
>> > -Tommy
>> > ________________________________________
>> > From: Navina Ramesh [nram...@linkedin.com.INVALID]
>> > Sent: Thursday, July 30, 2015 8:40 PM
>> > To: dev@samza.apache.org
>> > Subject: Re: Coordinator URL always 127.0.0.1
>> >
>> > Hi Tommy,
>> > Yi is right. Container start is coordinated by the AppMaster using an
>> > NMClient. Container host name and port is provided by the RM during
>> > allocation.
>> > In Yarn (at least, afaik), when the node joins a cluster, the NM
>> registers
>> > itself with the RM. So, the NM might still be using
>> > getLocalhost.getAddress().
>> >
>> > I don't know of any other way to programmatically fetch the machine's
>> > hostname (apart from some hacky shell commands).
>> >
>> > Cheers,
>> > Navina
>> >
>> > On Thu, Jul 30, 2015 at 5:23 PM, Yi Pan <nickpa...@gmail.com> wrote:
>> >
>> > > Hi, Tommy,
>> > >
>> > > Yeah, I agree that the current implementation is not bullet-proof to
>> any
>> > > different networking configuration on the host. As for the AM <->
>> > container
>> > > communication, if I am not mistaken, it is through the NMClient and
>> the
>> > > node HTTP address is wrapped within the Container object returned from
>> > RM.
>> > > I am not very familiar with that part of source code. Navina may be
>> able
>> > to
>> > > help more here.
>> > >
>> > > -Yi
>> > >
>> > > On Thu, Jul 30, 2015 at 4:27 PM, Thomas Becker <tobec...@tivo.com>
>> > wrote:
>> > >
>> > > > Hi Yi,
>> > > > Thanks a lot for your reply. I don't doubt we can get it to work by
>> > > > mucking with the networking configuration, but to me this feels
>> like a
>> > > > workaround, not a solution.
>> > InetAddress.getLocalHost().getHostAddress()
>> > > is
>> > > > not a reliable way of obtaining an IP that other machines can
>> connect
>> > to.
>> > > > Just today I tested on several Linux distros and it did not work on
>> any
>> > > of
>> > > > them. Can we do something more robust here? How does the container
>> > > > communicate status to the AM?
>> > > >
>> > > > -Tommy
>> > > >
>> > > > ________________________________________
>> > > > From: Yi Pan [nickpa...@gmail.com]
>> > > > Sent: Thursday, July 30, 2015 6:48 PM
>> > > > To: dev@samza.apache.org
>> > > > Subject: Re: Coordinator URL always 127.0.0.1
>> > > >
>> > > > Hi, Tommy,
>> > > >
>> > > > I think that it might be a commonly asked question regarding to
>> > multiple
>> > > > IPs on a single host. A common trick w/o changing code is (copied
>> from
>> > > SO:
>> > > >
>> > > >
>> > >
>> >
>> http://stackoverflow.com/questions/2381316/java-inetaddress-getlocalhost-returns-127-0-0-1-how-to-get-real-ip
>> > > > )
>> > > >
>> > > > {code}
>> > > >
>> > > > 1.
>> > > >
>> > > > Find your host name. Type: hostname. For example, you find your
>> > > hostname
>> > > > is mycomputer.xzy.com
>> > > > 2.
>> > > >
>> > > > Put your host name in your hosts file. /etc/hosts . Such as
>> > > >
>> > > > 10.50.16.136 mycomputer.xzy.com
>> > > >
>> > > >
>> > > > {code}
>> > > >
>> > > > -Yi
>> > > >
>> > > > On Thu, Jul 30, 2015 at 11:35 AM, Tommy Becker <tobec...@tivo.com>
>> > > wrote:
>> > > >
>> > > > > We are testing some jobs on a YARN grid and noticed they are often
>> > not
>> > > > > starting up properly due to being unable to connect to the job
>> > > > coordinator.
>> > > > > After some investigation it seems as if the jobs are always
>> getting a
>> > > > > coordinator URL of http://127.0.0.1:<port> But my understanding
>> is
>> > > that
>> > > > > the coordinator runs only in the AM, so I'd expect these URLs to
>> more
>> > > > often
>> > > > > than not be to some other machine. Looking at the code however,
>> I'm
>> > > not
>> > > > > sure how that would ever happen since the URL for the coordinator
>> > > always
>> > > > > comes from InetAddress.getLocalHost().getHostAddress() in
>> > > > > org.apache.samza.coordinator.server.HttpServer#getUrl
>> > > > >
>> > > > > Am I off base here? Because I don't see how this is ever going to
>> > work
>> > > > in
>> > > > > scenarios where the AM is on a different node than the containers.
>> > > > >
>> > > > > --
>> > > > > Tommy Becker
>> > > > > Senior Software Engineer
>> > > > >
>> > > > > Digitalsmiths
>> > > > > A TiVo Company
>> > > > >
>> > > > > www.digitalsmiths.com<http://www.digitalsmiths.com>
>> > > > > tobec...@tivo.com<mailto:tobec...@tivo.com>
>> > > > >
>> > > > > ________________________________
>> > > > >
>> > > > > This email and any attachments may contain confidential and
>> > privileged
>> > > > > material for the sole use of the intended recipient. Any review,
>> > > copying,
>> > > > > or distribution of this email (or any attachments) by others is
>> > > > prohibited.
>> > > > > If you are not the intended recipient, please contact the sender
>> > > > > immediately and permanently delete this email and any
>> attachments. No
>> > > > > employee or agent of TiVo Inc. is authorized to conclude any
>> binding
>> > > > > agreement on behalf of TiVo Inc. by email. Binding agreements with
>> > TiVo
>> > > > > Inc. may only be made by a signed written agreement.
>> > > > >
>> > > >
>> > > > ________________________________
>> > > >
>> > > > This email and any attachments may contain confidential and
>> privileged
>> > > > material for the sole use of the intended recipient. Any review,
>> > copying,
>> > > > or distribution of this email (or any attachments) by others is
>> > > prohibited.
>> > > > If you are not the intended recipient, please contact the sender
>> > > > immediately and permanently delete this email and any attachments.
>> No
>> > > > employee or agent of TiVo Inc. is authorized to conclude any binding
>> > > > agreement on behalf of TiVo Inc. by email. Binding agreements with
>> TiVo
>> > > > Inc. may only be made by a signed written agreement.
>> > > >
>> > >
>> >
>> >
>> >
>> > --
>> > Navina R.
>> >
>> > ________________________________
>> >
>> > This email and any attachments may contain confidential and privileged
>> > material for the sole use of the intended recipient. Any review,
>> copying,
>> > or distribution of this email (or any attachments) by others is
>> prohibited.
>> > If you are not the intended recipient, please contact the sender
>> > immediately and permanently delete this email and any attachments. No
>> > employee or agent of TiVo Inc. is authorized to conclude any binding
>> > agreement on behalf of TiVo Inc. by email. Binding agreements with TiVo
>> > Inc. may only be made by a signed written agreement.
>> >
>>
>>
>>
>> --
>> Navina R.
>>
>
>
