ELB Health Check return code

You can have TCP and HTTP health checks. A TCP health check will simply check if the web page exists (can be pinged essentially) a HTTP health check needs to return a 200 to pass the health check. More can be found here:
http://stackoverflow.com/questions/23689333/how-to-instruct-an-aws-elb-to-consider-a-health-check-that-returns-a-403-code-as

AWS ELB instances tied to ELB and ip addresses

The Amazon Elastic Load Balancer takes care of scaling out the number of underlying EC2 instances that make up the software virtual load balancer that is the Amazon ELB. However, you may want to determine the number of instances that are servicing your requests if you plan to scale out the number of users for a large promotion or for processing of a large number of users.  Determining the number of underlying instances is easy. You can simply use the host or dig commands using the ELB DNS name. There will be a minimum of one EC2 instance for each AZ that the ELB is servicing.

1. [ec2-user@ip-10-0-0-50 ~]$host ReachForceAutoScalingELB-1342887266.us-west-2.elb.amazonaws.com
ReachForceAutoScalingELB-1342887266.us-west-2.elb.amazonaws.com has address 50.112.140.192
ReachForceAutoScalingELB-1342887266.us-west-2.elb.amazonaws.com has address 50.112.183.144


2. [ec2-user@ip-10-0-0-50 ~]$ dig ReachForceAutoScalingELB-1342887266.us-west-2.elb.amazonaws.com

; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.17.rc1.28.amzn1 <<>> ReachForceAutoScalingELB-1342887266.us-west-2.elb.amazonaws.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 813
;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;ReachForceAutoScalingELB-1142887282.us-west-2.elb.amazonaws.com. IN A

;; ANSWER SECTION:
ReachForceAutoScalingELB-1342887266.us-west-2.elb.amazonaws.com. 30 IN A 50.112.183.144
ReachForceAutoScalingELB-1342887266.us-west-2.elb.amazonaws.com. 30 IN A 50.112.140.192

;; Query time: 1 msec
;; SERVER: 10.0.0.2#53(10.0.0.2)
;; WHEN: Fri Jun  6 12:31:34 2014
;; MSG SIZE  rcvd: 113

Oracle specific protocol support on AWS ELB

Some Oracle customers are running Oracle specific protocols and when they move to AWS they would like to know if AWS services (such as ELB) support these products.  AWS ELB supports the HTTP, TCP, HTTPS and SSL protocols.  Oracle UCM IDC protocol is not supported with AWS ELB.  In looking at common on premise software and hardware load balancers (F5, Riverbed etc), I do not see any that support Intradoc (IDC).  The more important question to ask is: "What load balancer do you use on premise to load balance IDC traffic?"  If it is a software load balancer, you could run this on an EC2 instances.>

Another protocol that some Oracle customers run is Sockets Direct Protocol (SDP). SDP is an industry-standard wire protocol between InfiniBand network peers. When used over an InfiniBand network, SDP reduces TCP/IP overhead by eliminating intermediate replication of data and transferring most of the messaging burden away from the CPU and onto the network hardware.  This protocol is not supported on AWS.