I've a Amazon ELB behind which there are 3 EC2 instances distributed across 3 zones.
Following are extracts of access logs on each instances:
1st instance(Zone A):
10.210.214.231 - - [17/Sep/2011:15:40:16 -0400] "GET /healthcheck.html HTTP/1.1" 200 194 "-" "ELB-HealthChecker/1.0"
10.223.33.43 - - [17/Sep/2011:15:40:16 -0400] "GET /healthcheck.html HTTP/1.1" 200 194 "-" "ELB-HealthChecker/1.0"
10.210.214.231 - - [17/Sep/2011:15:40:17 -0400] "GET /healthcheck.html HTTP/1.1" 200 194 "-" "ELB-HealthChecker/1.0"
10.223.33.43 - - [17/Sep/2011:15:40:17 -0400] "GET /healthcheck.html HTTP/1.1" 200 194 "-" "ELB-HealthChecker/1.0"
2nd instance(Zone C):
10.116.114.11 - - [17/Sep/2011:15:40:16 -0400] "GET /healthcheck.html HTTP/1.1" 200 194 "-" "ELB-HealthChecker/1.0"
10.116.114.11 - - [17/Sep/2011:15:40:16 -0400] "GET /healthcheck.html HTTP/1.1" 200 194 "-" "ELB-HealthChecker/1.0"
3rd instance(Zone D):
10.223.33.43 - - [17/Sep/2011:15:40:16 -0400] "GET /healthcheck.html HTTP/1.1" 200 194 "-" "ELB-HealthChecker/1.0"
10.223.33.43 - - [17/Sep/2011:15:40:16 -0400] "GET /healthcheck.html HTTP/1.1" 200 194 "-" "ELB-HealthChecker/1.0"
Eager to know how come traffic is coming from separate IP's on instances behind same ELB. Also, 10.223.33.43 is showing up on two of instances. Why is that so?
Do LB's exist in each zone where an instance is launched? Sounds weird, but having separate IP's in access logs make me believe it..