[SR-Users] Kamailio Load Balancer Architecture

[Daniel Tryba]

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.