Alternate query results from DNS possible??
K.Y...@amc.uva.nl
We need to do load sharing over two machines to which
our users telnet and we would like to do this in a
manner transparent to our users. So a possibility is
to let our name server give the first ip-nr and then
the second in response the the queries to resolve the
hostname. Is there an easy way to do this, and if not
is there a less easy way to do this?
A course way I've come up with is to switch databases
every x minutes and send a kill -SIGHUP to named, but
I don't like that idea very much.
BTW we are running named on a SUN (if it were Linux I
could try to patch te source code :)
Thanx in advance, Ewald...
--
Ewald H. Beekman, Academical Medical Center, The Netherlands
E.H.B...@amc.uva.nl, phone +31 20 5667085, fax .. 5669020
Jesper Skriver
K.Y...@AMC.UVA.NL wrote:
>
>We need to do load sharing over two machines to which
>our users telnet and we would like to do this in a
>manner transparent to our users. So a possibility is
>to let our name server give the first ip-nr and then
>the second in response the the queries to resolve the
>hostname. Is there an easy way to do this, and if not
>is there a less easy way to do this?
>A course way I've come up with is to switch databases
>every x minutes and send a kill -SIGHUP to named, but
>I don't like that idea very much.
>BTW we are running named on a SUN (if it were Linux I
>could try to patch te source code :)
>Thanx in advance, Ewald...
Bind versions af of ? ( I know for sure that 4.9.3 supported this
feature) supports multiple A records, which does exactly what you
wants.
foo.bar.com IN A 193.10.1.1
IN A 193.10.1.2
does the trick
/Jesper
Frank Wetzels
Ewald,
fpmw> We need to do load sharing over two machines to which
fpmw> our users telnet and we would like to do this in a
fpmw> manner transparent to our users. So a possibility is
fpmw> to let our name server give the first ip-nr and then
fpmw> the second in response the the queries to resolve the
fpmw> hostname. Is there an easy way to do this, and if not
fpmw> is there a less easy way to do this?
fpmw> A course way I've come up with is to switch databases
fpmw> every x minutes and send a kill -SIGHUP to named, but
fpmw> I don't like that idea very much.
fpmw> BTW we are running named on a SUN (if it were Linux I
fpmw> could try to patch te source code :)
fpmw> Thanx in advance, Ewald...
Just kill -HUP has more consequences, you should update your
serial number in your soa-record in order to make the secondary
take over these changes (If you rely on the fact that just
the primary is queried, then you don't need a secondary anyway).
So, also should implement this on all your secondaries.
The out of syncness is not a problem, as a matter a fact, when
they are out of sync, you got loadsharing anyway.
BTW on your SUN, you're probably running a version of
bind, so your *can* patch the source code, but it is risky.
As i rember, i believe there was some discussion a while ago
about 'rotating' IP addresses connected to one hostname, but
i don't know where it ended.
Maybe somebody knows about this?
Frank
--
-------------------------------------------------
F.P.M. Wetzels Informatiseringscentrum
Turfdraagsterpad 9 Voice +31 20 5252214
1012 XT Amsterdam-Centrum Fax +31 20 5252084
-------------------------------------------------
There are only one type of mathmaticians, those
who can count and those who cannot count.
m...@f5.com
On Thu, 28 Nov 1996 K.Y...@amc.uva.nl wrote:
>
> We need to do load sharing over two machines to which
> our users telnet and we would like to do this in a
> manner transparent to our users. So a possibility is
> to let our name server give the first ip-nr and then
> the second in response the the queries to resolve the
> hostname. Is there an easy way to do this, and if not
> is there a less easy way to do this?
>
sure, read up on rotary dns and nfs ( prolly want to look
at the automounter or something similar )... there are also
a few commercial products which can do this depending on
the manner in which you configure the hosts you are offering
service on: our product, "Big/IP" ( www.f5.com ), Cisco's
Local Director, and some other software solutions which
are directed more towards load balancing http content, but
might be bent towards your needs... really, however you want
to distribute connections, with any "interactive session"
service the issue is really one of how the hosts replicate
the content ( in your case the users home directories, and
the services offered by the hosts )...
hope that helps,
m.
Matt Sommer, Network Systems Engineer InterNIC: MMS26
F5 Labs, Inc. 1218 3rd Ave., Suite 508 Seattle, WA 98101
e-mail: m...@f5.com Voice: 206.447.1817 Fax: 206.447.9636
1A7B3D4D 1996/09/27 = DD 49 89 EE 81 FF AC CA A1 19 A1 75 87 22 DC 53
K.Y...@amc.uva.nl
> fpmw> We need to do load sharing over two machines to which
> fpmw> our users telnet and we would like to do this in a
> fpmw> manner transparent to our users. So a possibility is
> fpmw> to let our name server give the first ip-nr and then
> fpmw> the second in response the the queries to resolve the
> fpmw> hostname. Is there an easy way to do this, and if not
> fpmw> is there a less easy way to do this?
> BTW on your SUN, you're probably running a version of
> bind, so your *can* patch the source code, but it is risky.
>
> As i rember, i believe there was some discussion a while ago
> about 'rotating' IP addresses connected to one hostname, but
> i don't know where it ended.
>
> Maybe somebody knows about this?
This is actually a FAQ. Many thanks for your help.
It turned out to be plain & simple; what should be done is:
machineA IN A a.b.c.d
machineB IN A a.b.c.e
cluster IN CNAME machineA
CNAME machineB
First attempt will connect you to A & second to B in a round robbin fashion.
There's a perlscript to do real load balancing. If someone needs it, i'll look
it up for you.
Ken
IainP
> >
>
> at the automounter or something similar )... there are also
> a few commercial products which can do this depending on
> the manner in which you configure the hosts you are offering
> service on: our product, "Big/IP" ( www.f5.com ), Cisco's
> Local Director, and some other software solutions which
> are directed more towards load balancing http content, but
> might be bent towards your needs... really, however you want
> to distribute connections, with any "interactive session"
> service the issue is really one of how the hosts replicate
> the content ( in your case the users home directories, and
> the services offered by the hosts )...
>
> hope that helps,
>
> m.
This now works automatically in the latest versions of BIND.
Just put the entries in the forward file as follows;
www IN A 1.2.3.4
IN A 1.2.3.5
IN A 1.2.3.6
Queries the should return a different address each time.
IainP
Larry Kahn
In article <961204085...@dopey.amc.uva.nl>, K.Y...@AMC.UVA.NL says...
\
NO this is against the rfc's what you should do is
cluster in A a.b.c.d
cluster in A a.b.c.e
Angelos Karageorgiou
In article <1996120316...@mail.ic.uva.nl>,
Frank Wetzels <wet...@ic.uva.nl> wrote:
>
>As i rember, i believe there was some discussion a while ago
>about 'rotating' IP addresses connected to one hostname, but
>i don't know where it ended.
>
>Maybe somebody knows about this?
Well i do not have it in fornt of me , but I clearly remember a flag in the
configuration header file , config.h ? the said the equivalent of rotate ip
numbers , this effectively rotates the ip numbers of a host at each query
at the server.
Also , always remember to read the README file it contains most of the
time all of the asnwers that an average mortal seeks . One just needs patience
to go through it, and not expect the mighty net to provide an immediate answer.
--
--
In the internet, nothing works all of the time !