Configuring AWS Elastic Load Balancer as LB for API Gateway Cluster & API Portal

[Anon Anon]

Hi CA Community,

 

Would like to ask if there is example of guides on implementing AWS ELB as a LB for API Gateway Cluster setup. 

 

From my understanding AWS ELB does not have a elastic IP both for Internal IP and external IP to communicate between instances within the same cluster.

 

In that case, with just a external hostname (for external ELB) will this load balancer be suitable for setting up Gateway cluster? I am thinking if the IP addresses change dynamically, it will have issue with my setup on /etc/hosts on my gateway nodes of the cluster. Alternatively, creating an internal ELB might help but it still has the same problems without a static IP address for internal IP. 

 

Down the road, this might cause issues for API Portal <> API Gateway setup because the cluster IP address can't resolve correctly without a proper IP as it cannot take a hostname. While I can ping the hostname of the external LB to get the IP address, it is still not static by nature.

 

Hope I can get some advice on this setup on how to do it correctly with AWS Load Balancer as a choice of LB to integrate with Layer7.

 

Thanks for helping!

[Jay Thorne]

I'm not sure why you'd need any /etc/hosts entry so that part of your question is unclear, but best practices for us has always been to use both your DNS provider and a static external address for the ELB to set up a destination and certificate that is relevant to your organization. 

 

Changing IP address dynamically isn't something you should do - even if it saves you a little bit of money, lots of client software caches DNS lookups long enough that I wouldn't depend on DNS refresh times. 

 

Use hostnames and real DNS entries. You could use ip addresses and a hosts file internally, but that starts to be confusing to me. Are you assuming that once up, an instance changes IP addresses? I assure you, this doesn't happen in AWS, it only changes if you leave the instance down for a long time, so the portal will be at a well known, nearly static address.