How do I set up an ELB cluster?

Question

I read this from https://docs.wso2.com/display/ELB211/FAQ#FAQ-HowdoImaketheELBhighlyavailable , the FAQ section of WSO2's ELB documentation :

How do I make the ELB highly available? Create an ELB cluster and route the requests to them through a hardware load balancer.

How exactly do I set up an ELB cluster? I looked at the other clustering docs on wso2.com (https://docs.wso2.com/display/CLUSTER420) and didn't see how to cluster the ELB itself. My best guess is that I just get one ELB working and then set up another instance with the identical configuration but on a different host or port and then let the hardware load balancer do the rest. Is that all that's required?

Just found this, but haven't yet tried it:

http://wso2.com/library/tutorials/2013/09/make-wso2-elb-highly-available-through-aws-elb/

Answer 1

You must specify a different port value for each ELB in the cluster. Do this configuration for both the ELBs. This configuration is done primarily to make both ELBs aware of each other. If both your well-known members are ELBs, then each ELB has to know about the other ELB in order to create the ELB cluster. To do that, in each ELB's cluster configuration, you have to mention the other ELB. This is exceptionally helpful in scenarios when one ELB restarts and it would need to get the existing cluster information to serve requests again. To do that, it would need to communicate with the other ELB.