[SR-Users] Kamailio Load Balancer Architecture

[Colin Morelli]

Daryn,

That response was more general, not necessarily directed at you!

DNS-based load balancing has always been problematic for clients. They tend
to not properly balance across SRV records, or failover to secondary A
records.

However, I think the best solution would be something like what Daniel
mentioned - to have multiple (maybe 2-4 but the number really depends on
your availability and scalability requirements) Kamailio instances at the
edge, each with a corresponding standby ready to take over that IP in a
failover scenario.

Combine that setup with rotating the A and SRV records in your DNS server
(most DNS servers support automatically rotating the records in a
response), and you should be able to support all kinds of clients.

Best,
Colin

On Thu, Jun 30, 2016 at 11:49 AM Daniel Tryba <d.tryba at pocos.nl> wrote:

> On Thu, Jun 30, 2016 at 05:15:19PM +0200, Giacomo Vacca wrote:
> > Remember though that the Load Balancer will be
> > your Single Point Of Failure. If the Load Balancer dies, for any reason,
> > the service is not available.
> ...
> > Depending on the capabilities of the clients you may consider removing
> the
> > Load Balancer from the equation and perform DNS-based load balancing
> across
> > your Proxy/Registrar/PSTN Gw instances. You'd be removing a SPOF, use one
> > fewer machine, and simplify the architecture. This is not always possible
> > to achieve though, because it delegates load balancing and fail over to
> the
> > clients.
>
> Clients are to stupid to do this, you have to target the lowest common
> denominator which only connect to a single ip. The loadbalancer is one
> of the most simple possible config of kamailio possible (dispatcher and
> path).
>
> So if you worry (rightly so) about a single point of failure in the
> loadbalancer setup, make that one redundant by using a failover
> mechanisme (heartbeat/keepalive/whatever). And having multiple instances
> of this setup to use DNS based loadbalancing or simple primary/secondary
> endpoints for the clients to connect to make any kind of failover
> mechanisme for any type of client possible. The resources needed for a
> loadbalancer are the least of all machines needed.
>
>
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