Failure modes for ELB are not documented anywhere, and there’s no SLA for ELB. Sometimes there are service interruptions (rarely, actually) but the ELB does “come back to life” with the same endpoint name.

first thank for the help. I’m running jmeter with the following param -Jsun.net.inetaddr.ttl=0, and the script is configured in order to use an HTTP Request Defaults pointing to the lb dns name.
How do I check from the browser which webserver responds to the request? Shall I just check IIS logs and see if they all contain requests from my browser?
Thanks again

Did you start JMeter’s JVM with the sun.net.inetaddr.ttl property set appropriately?
Are you hitting the ELB’s DNS name in JMeter?
What happens if you hit the ELB’s DNS name via a browser and constantly refresh the page – does the traffic get distributed?

the trigger adds the instance to the elb automatically. I’ve tried to disable the keepalive flag in the Jmeter script, but still I don’t see the traffic equally distributed among the instances.

You should double-check that the AutoScaling group is connected to the ELB. As per ChrisK@AWS in this thread:

AutoScaling will not add instances to the ELB if you do not specify the ELB name in the AutoScalingGroup. Without the ELB, AutoScaling will just launch the instance and you can add the instance to your ELB whenever the instance is ready. Note however that, when AutoScaling terminates an instance, without the ELB configured, AutoScaling will not be able to remove the instance from ELB.

great post!

I’m trying to load test a website using jmeter and I’ve configured elb as member of eu-west-1a only. I’ve also configure an autoscaling trigger, in order to increase the number of instance if the load is above a threshold. I’m running jmeter from a large instance in the same availability zone. What I notice is that, once the additional instance is up and running, it doesn’t receive any traffic, while the old one stays overloaded. Am I doing anything wrong in the config? Both AppCookieStickinessPolicies LBCookieStickinessPolicies are both unset. Any thoughts?
Thanks for the great post

Nicola

I don’t know of any other way to get the client’s IP address via HTTPS when using ELB other than the workaround I propose in that thread. Perhaps other readers know of something?

As of now is there any work around for capturing client ip address through HTTPS traffic, other than the work around you had mentioned in the AWS Forum

http://developer.amazonwebservices.com/connect/thread.jspa?messageID=176811

I have a server that is configured to handle both HTTP annd HTTPS traffic. I have set the X-Forwarded-For in apache.conf and is capturing client ip address for http traffic without any issues?

So is it like as of now we don’t have any solution to capture client ip through HTTPS traffic when using ELB?

Thanks for the link to that paper – a very interesting read!

Two m1.small instances will have better network performance than a single c1.medium instance – Figures 3 and 4 in the paper show this. For network-intensive applications m1.smalls are more economical.