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Re: [Testbed-admins] Node problems after dhcp/tftp re-configuration



Thanks for the pointers.

I logged into the node and 'tmcc bossinfo' fails as expected but with thie error: 'gethostbyname(UNKNOWN) failed'. 
If I ping 'boss', or the full domain 'boss.mydomain' it resolves to the correct IP and responds happily. 

I traced through the code and realized it wasent the DNS failing but the binary failing to actually pass the string 'boss' into the gethostbyname() function.
I noticed it was looking for a file called 'bossnode' in several directories and when found it used the single string inside as the domain name of boss.

After doing: echo "boss" > /etc/emulab/bossnode  , it suddenly started working and registers with boss

What would be the reason that the file didnt exist?

Thanks for your help!

On Fri, Jun 4, 2010 at 4:33 PM, Leigh Stoller <stoller@flux.utah.edu> wrote:
> I had everything up and working last week and then I changed the
> interface the dhcpd and tftpd were listening on. The new interface
> is on a different vlan but still can read the experiment nodes but
> on a different interface of theirs. I did this to isolate this
> acitivity from the rest of the network that I shared (used mac
> filtering with dhcp).
>
> I managed to get it all working except that when the nodes finish
> booting the freebsd.newnode image, they spit out a couple errors
> related to resolving the boss which fly by and at the very end I get
> a "*** Fatal Error 1: Unable to parse boss name from ' '". The last
> bit is ' ' or an empty string.
>
> Is this a DNS issue that I simply didnt notice or is it in a config
> file somewhere on the image? Ive narrowed it down to the tmcc.bin
> tool. How does tmcc.bin resolve the boss name?

I can't say much about the first two paragraphs since only you know
what you had and what you did to break it :-)

But, I can tell you how tmcc figures out who boss is ... it looks to
see who its DNS server. If this fails:

pc> /usr/local/etc/emulab/tmcc.bin bossinfo

Then the pc is not getting proper DNS service from boss. That could be
for any number of reasons. Does /etc/resolv.conf on the pc look right?
Can the pc ping boss' IP? You might want to closely track the other
thread that is going with Barry Trent ... lots of diagnostic overlap.

Lbs


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Chris Benninger
University of Victoria, Computer Science
cbenning@cs.uvic.ca
http://syfor.com

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