Hi list, I'd like you to share the experience about running Kannel as SMS gateway in clustered environment, when there are more than one node and fail over is basically more important than load balancing. Idea behind the scenes is that on each node there is an application server running which uses Kannel for MT SMS and Wap Push (via PPG) and the goal is to be sure that if one node goes down, application continues to work. In front of the nodes there is a load balancer which is able to detect if a particular node is dead then requests should be redirected to the one which is alive.
According to my tests with SMPP drivers, neither SMSC worked with parallel transmitters and transceivers either and SMSC mostly blames with 0x00000005 (ESME Already in Bound State) or other error with the similar meaning. Saying parallel I mean having a Kannel instance running same time on the each node. So having setup of just two nodes, I only achieved kind of "fail over" with the script on both nodes constantly checking if other node is alive, hence assuring that there is one Kannel instance between nodes in a time. Load balancer then directs user to the "active" node. Are there any better setups as such? Looks like at least with SMPP in "real" clustering environment there should be several SMSC in order to achieve fail over/load balancing. Thanks. -- Dziugas
