[mpich-discuss] Can't form mpi ring

[Reuti]

Hi,

Am 27.09.2010 um 12:21 schrieb Akshey Jawa:

> I am facing problem in using mpich2 on my computer systems(having Ubuntu).
> 
> Here is what I tried:
> 
> 1) I ran 'mpd &' on one machine and then I ran 'mpdtrace -l' on the same machine. I got this as output: "my-lappy_53430 (127.0.1.1)"
> 2) On another machine I ran 'mpd -h -p 53430 &' and got this error:

you don't need a DNS for this to work, but some unique addresses for each of the machines, so that you can also login from one machine to the other by ssh for example.


> akshey-desktop_39993: conn error in connect_lhs: Connection timed out  
> akshey-desktop_39993 (connect_lhs 924): failed to connect to lhs at 10.2.28.137 52430  

Where is 10.2.28.137 coming from?

> akshey-desktop_39993 (enter_ring 879): lhs connect failed  
> akshey-desktop_39993 (run 267): failed to enter ring  
> 
> 
> 
> Can you please help with this issue? I tried to ping and ssh the first machine(on which mpd is running) from the second machine and it worked.
> 
> After this I executed 'mpdheck' on the first machine, I got this as output:
> 
> 
> *** first ipaddr for this host (via my-lappy) is: 127.0.1.1
> 
> These are the contents of /etc/hosts of the first machine:
> 
> 
> 127.0.0.1   localhost
> 127.0.1.1   my-lappy

Make this a address out of the private ones and include two entries for both machines on both of them. Either:

127.0.0.1 localhost
10.0.1.1 my-lappy
10.0.1.2 my-desktop

or

127.0.0.1 localhost
192.168.0.1 my-lappy
192.168.0.2 my-desktop

and setup your network to use these addresses. Then try on both sides a `ping my-lappy` resp. `ping my-desktop`. When this works, you can try to start the mpds again.

-- Reuti


> # The following lines are desirable for IPv6 capable hosts
> ::1     localhost ip6-localhost ip6-loopback
> fe00::0 ip6-localnet
> ff00::0 ip6-mcastprefix
> ff02::1 ip6-allnodes
> ff02::2 ip6-allrouters
> ff02::3 ip6-allhosts
> 
> Then I ran 'mpdcheck -l' and got this as output:
> 
> 
>     **********  
>     Your unqualified hostname resolves to 127.0.0.1, which is  
>     the IP address reserved for localhost. This likely means that  
>     you have a line similar to this one in your /etc/hosts file:  
>     127.0.0.1   $uqhn  
>     This should perhaps be changed to the following:  
>     127.0.0.1   localhost.localdomain localhost  
>     **********  
> 
> Even after changing the first line of /etc/hosts to "127.0.0.1 localhost.localdomain localhost" I still got the same output from 'mpdcheck -l'
> 
> Please note that I do not have access to the DNS server of the network and these machines do not have a DNS entry in the DNS server. (I think this should not be a problem because we can always use IP addresses instead of hostnames. Isn't it so?)
> 
> Thanks,
> 
> Akshey
> 
> 
> 
> 
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