round-robin

[j773303]

I'm trying the DNS round-robin function, assume the A hostname, has 3 ip-address, 10.1.1.1 and 10.1.1.2 and 10.1.1.3, in BIND 8.12, while nslookup A, it cound be found by 10.1.1.1 10.1.1.2 10.1.1.3 by order, but when I upgrate to BIND9.2, the nslookup A would not get the order, it will get the random order, such as 10.1.1.2 10.1.1.1 10.1.1.3.... Does any one has the experience about BIND9.2 round-robin?

[Michael Tully]

Have a look at this posting:

http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=202397

[j773303]

I'm not sure the configuration problem. But now the nslookup the get random order, so the BIND 9.2 round-robin has enabled. My mean is why BIND 9.2 round-robin is rand order search? Does any one has the same problem? Or this is a featuer or bug in BIND 9.2?

[j773303]

Does anyone has the experience configure round-robin in BIND 9.2? What's your nslookup hostname search order?

[Norman_21]

Hi,

This is from the Release notes of Bind 9.2
Unsupported Features
The following BIND 8.1.2 options are not supported in BIND 9.2.0:
â ¢ no-round-robin
This option was used in BIND 8.1.2 to turn off the default round
robin, which cycles returned IP addresses for multi-homed hosts.

Look here, page 21:
http://docs.hp.com/hpux/onlinedocs/B5969-4338/B5969-4338.pdf

Hope this help
Btw: what version are you runnin

[Norman_21]

Another release note for 11.0
http://docs.hp.com/hpux/onlinedocs/5969-4366/5969-4366.html

[Sergejs Svitnevs · Accepted solution]

The code in Bind 9.0 was changed so that the nameserver doesn't have to keep track of
state regarding which "position" the rotary is in at any given point in time.

in Bind 8.x RRSET-ORDER option defines the order in which multiple records of the same type are returned.

RRSET-ORDER IS NOT YET IMPLEMENTED IN BIND 9.

Current BIND implementations return multiple records using a random-cyclic order (the starting address is randomly chosen and thereafter round-robin order).

Regards,
Sergejs

[j773303]

Thank you all for the good suggestions. I'm still have concern, that's meaning load-lancing for round-robin, if BIND9.X support round-robin, but get the random order, that's means the nslookup Ahost would get the same ip-address even if configure 3 ip-adress for Ahost. But in BIND 8.X, the round-robin will fit the load-balancing function. Any one can tell me, why BIND9.x modify the code for round-robin (load-balancing)? How does BIND9.x reached the load-balancing?

[Norman_21]

I have read somewhere that it's recommended to use dig instead of nslookup!

[Sergejs Svitnevs]

For the inbound load balancing and redundancy of your servers I suggest that you look into the "real" Load Balancing/Distribution Solutions (Alteon switches, Cisco LocalDirector, www.linux-vs.org, http://www.redhat.com/support/wpapers/piranha/,....).

Regards,
Sergejs

[Sander Sokk]

Hmm, I think with bind9 all is working just fine. You may ask from yourself, what is the goal of the round robin? Answer is to reduce traffic for those hosts. You see, on huge corporations there is always a problem, when it come's to reaching some host (read hostname) over internet and here come's to aid round robin. Let's assume that one hosts is daily in overload. Administrator then divides this traffic to multiple physical hosts (eg. 10.1.1.2 etc.) where runs original hosts mirrored webservice or smth. When someone tries access from internet to that hosts it gets to one of these hosts dynamically. But when some physical host dies then DNS don'nt know anything about that. Unfortunatelly here come's administrator again to favor, it musts wipe out that hosts address from dns round robin.

Cheers,

Sander