load balancing

Matus UHLAR - fantomas uhlar at fantomas.sk
Wed Sep 19 10:14:35 UTC 2018

On 18.09.18 14:39, SIMON BABY wrote:
>I am looking DNS RR distribution. (DNS Round Robin Load distribution).
>Round robin DNS is often used to load balance requests between a number of Web
>servers <https://en.wikipedia.org/wiki/Web_server>.
> For example, a company
>has one domain name and three identical copies of the same web site
>residing on three servers with three different IP addresses. When one user
>accesses the home page it will be sent to the first IP address. The second
>user who accesses the home page will be sent to the next IP address, and
>the third user will be sent to the third IP address. In each case, once the
>IP address is given out, it goes to the end of the list. The fourth user,
>therefore, will be sent to the first IP address, and so forth.

This is standard and supoprted DNS feature.

However, it's not designed to do failover switching.

Each browser may (and apparently will - correct me if I'm wrong) access
random of those IP addresses for each request and since web pages are
usually assembled of tens of objects, each one may be fetched from different

Long time ago (>15 years) we have tried using this for failover with bad
results (half of the web page not read).

If you want failover, I recommend L3 switch like linux ipvs or similar.

>> On Tue, Sep 18, 2018 at 4:01 PM SIMON BABY <simonkbaby at gmail.com> wrote:
>>> Are we support load balancing with latest DNSSEC ? I have a DNSSEC
>>> application with unbound library. Do i have to add any extra configuration
>>> to support Load Balancing?

>On Tue, Sep 18, 2018 at 1:22 PM Warren Kumari <warren at kumari.net> wrote:
>> Your question is sufficiently light on detail that it cannot be
>> realistically answered.
>> What sort of load balancing?
>> 1: Traditional SLB - you hand out one IP address, and have a load balancer
>> widget which shares this to multiple backends?
>> 2: Global SLB - you hand out different IP addresses to different clients?
>> 3: Round Robin - you hand out different IP addresses, but randomly / in a
>> order, not tied to specific clients?
>> 4: Anycast - you hand out the same IP address, but this lives on multiple
>> sites, and routing takes care of getting people to the closest site?
>> 5: Multiple nameservers? Something else?
>> The term "load balance" is very vague / can be applied to multiple things
>> - for all of the above except  #2, this should just work without any
>> changes. GSLB *may* require more work, but may not. # 5 is sufficiently
>> undefined that it cannot really be answered :-)
>> What *exactly* is the question / scenario you are asking?

Matus UHLAR - fantomas, uhlar at fantomas.sk ; http://www.fantomas.sk/
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