Active-Active Registrar setup with users behind NAT persistence in event of server failure - sr-users

19 Feb 2020

Hi Guys,

I have a quick question wondered if anyone could provide some suggestions please?!

We have a setup of two registrars in EC2 (kamailio 4.4 running on debian VMs) which act in
an active/active fashion with a number of devices
behind NAT where  we use the DMQ dmq_t_replicate function to send the registration details
between each server and append the PATH parameter
so the registrar the device registered with is always associated with the client device.

This all works fine, the only issue is persistency should we have a failure of one of the
registrars, be it process or server and recovering the correct
PATH detail so the end device can still be reached.

I have tried this with separate databases with each registrar, which works when using
cache and db but I ideally want the same database for the two servers and not
change the architecture at this time unless it is a necessary.

I have also tested with dmq_usrloc but this again provides the usrlocation details of the
notification servers in the group(not path), again which I understand but I wondered
if there is anything else I could try or its just a question of in the event of a failure
half the registrations will be effected until it recovers and they
re-register again if I dont want to have separate databases (location tables) or I add
more network elements into the flow, such as HA pair or load balancer but just want to
make sure I have exhausted all options or consider the risk before I look to do this.

Many thanks!

Jon