[Gllug] SSH + Putty

[Narender]

On Thu, Nov 18, 2010 at 9:52 PM, John Hearns <hearnsj at googlemail.com> wrote:
> On 18 November 2010 15:41, Narender <narender.hooda at gmail.com> wrote:
>> I am trying to set up a hadoop  cluster(Linux machines) on 3 vm’s. As
>> of now I am using say 10.1.1.2/3/4.
>>
>>
>> I am currently facing an issue on 3/4.  I am unable to ssh localhost
>> on the boxes once I log on  to them via putty.
>
> Start from the top:  ifconfig -a   then    ping localhost
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Thank you John

i figured it out.


During configuration of hadoop, we need to ensure that a process will
be able to ssh to localhost

Investigating a bit further, it seemed that the ssh client was timing
out on the connection on these 2 machines.
On digging further for the reason of the time out, it seems that the
loopback interface was not right on 10.1.1.2/3.


Interestingly, the loopback interace details seem to be correct
/etc/sysconfig/network-scripts/ifcfg-lo has the right details and is
exactly the same in all of the machines.
Running  /sbin/ifconfig lo on a machine with the correct loopback interface

[jerry at DMYSQL-01 ~]$ /sbin/ifconfig lo
lo        Link encap:Local Loopback
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:839 errors:0 dropped:0 overruns:0 frame:0
          TX packets:839 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:93857 (91.6 KiB)  TX bytes:93857 (91.6 KiB)

Running it on one that was not correct

[jerry at DMYSQL-03 ~]$ /sbin/ifconfig lo
lo        Link encap:Local Loopback
          LOOPBACK  MTU:16436  Metric:1
          RX packets:8 errors:0 dropped:0 overruns:0 frame:0
          TX packets:8 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:560 (560.0 b)  TX bytes:560 (560.0 b)


You can see that the loopback interface is incorrectly set. Hence ssh
cannot connect to the loopback interface when it tries for localhost

Thank you again..


Best Regards
N
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