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MapReduce >> mail # user >> Hello! - Hadoop: System Requirements.

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RE: Hello! - Hadoop: System Requirements.
Thanks Mohammad...

Yep, the problem is when IP gets changed... And this will be the rule since I travel a lot for business reasons (I am a quality consultant, hotels here and there...). Also I am testing/learning now in order to give a recommendation to my BI manager in near future... single node is enough for now...

I've added the wlan IP address to the /etc/hosts file, but it is still impossible to ping myself, but it seems that I am "almost there"...
because If I ping RHEL6 (hostname), I've got an error massage (Destination host unreachable)
but if I ping the wlan IP address, it is ok (but Hadoop refuses to start: "Failed to retrieve hostname/IP from RHEL6.ccet.ufrn.br"...)

I guess that an association between RHEL6 hostname to this two IP addresses is needed, but I do not know if this is possible...

Here it is the hosts file:

---------------------------------------------------   localhost localhost.localdomain localhost4 localhost4.localdomain4
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6
# wireless RHEL6
# wired RHEL6
Thanks again!

Date: Wed, 15 Aug 2012 00:26:01 +0530
Subject: Re: Hello! - Hadoop: System Requirements.

Hello Cristian,
      No question is "dull"..I also do the same thing when stuck. Now,the reason behind your problem
is that when you switch from wired to wireless, the IP gets changed. Just use "ifconfig" command to
get the IP and paste it in your hosts file along with your hostname. BTW, are you using Hadoop in
pseudo or fully distributed mode??Also, if there is any need of this switching quite often just have 2
sets of configuration files.
    Mohammad Tariq
On Wed, Aug 15, 2012 at 12:16 AM, Cristian Carranza <[EMAIL PROTECTED]> wrote:

  Thanks again Mohammad!

  Please help me to go further on your advice, since I am not good dealing with hostnames and network conf...

  I am using a wired connection to the internet right now and can "ping myself" {ping <myhostname>} and IBI/Hadoop are running fine.

  But if I change to a wireless connection, I can neither ping myself anymore nor Hadoop.

  Having said that: What changes in network configuration files (hostname) and in /etc/hosts are necessary in order to ping myself again, this time with a wireless DHCP IP address?

  Really hope that this is not a dull question... but any help will be much appreciated.

  Date: Tue, 14 Aug 2012 19:50:28 +0530

  Subject: Re: Hello! - Hadoop: System Requirements.

  If you don't want to use static IP, use the hostname everywhere in your configuration. But you need to modify the /etc/hosts file everytime to reflect the changes.

      Mohammad Tariq
  On Tue, Aug 14, 2012 at 7:43 PM, Cristian Carranza <[EMAIL PROTECTED]> wrote:


    Thanks for your prompt response. But...
    Is there a way to use Hadoop without a static IP address with a VM?

    From: Julien Muller
    Sent: Tuesday, August 14, 2012 11:05 AM
    Subject: Re: Hello! - Hadoop: System Requirements.

    if your purpose is learn / dev / demo, it would be a good idea to use a VM.
    You will not only be able to use a static IP, but also keep copies of working systems, make some tests, learn how to setup a cluster with only 1 physical machine. And much more.


    2012/8/14 Cristian Carranza <[EMAIL PROTECTED]>

      Hello all in this list!

      Thank you Harsh J for your help! I decided to post it again in order to properly identify myself in the archive list.
      My name is Cristián and I am trying to learn Hadoop and to use it in near future...

      I’ve started to learn Hadoop via Infosphere BigInsights (IBI), Basic Edition, from IBM.
      But I am facing problems now that make me wonder if there are alternative ways to learn Hadoop.

      The biggest problem is that IBI demands a static IP address, and this is a tough requirement for me, since I travel a lot for business and always use IP address assigned via DHCP..
      Is there a way to use Hadoop without a static IP address?

      More general question: What are the system requirements for installation of Hadoop?

      Thank you in advance!

      Cristián Carranzal.