Dns round-robin not working despite *cache.ttl java options being set

Gatling (Open-Source)
1

Hi guys,

I’m running gatling against a bunch of servers load balanced over dns:

java.net.InetAddress.getAllByName(“my.proxy.net”)
res0: Array[java.net.InetAddress] = Array(my.proxy.net/10.70.129.38, my.proxy.net/10.70.5.7)

I also changed gatling.sh to avoid the JDK dns cache:

// gatling.sh last line
java -Dnetworkaddress.cache.ttl=0 -Dsun.net.inetaddr.ttl=0 $JAVA_OPTS -cp $CLASSPATH io.gatling.app.Gatling $@

However, running tcpdump I see that only one of the servers is taking all the hits. Is this something that I have to configure in Gatling (keep-alive, connection pooling, etc)?

Thanks for the help.

2

networkaddress.cache.ttl can’t be set on the command line, it has to be set up in java.security.

However, -Dsun.net.inetaddr.ttl=0 has the same effect.

Which version of Gatling do you use?
Which JDK?
What does your simulation look like? Do you have several users?

3

Note that you can also have Gatling perform load balancing for you with
baseUrls: https://github.com/excilys/gatling/wiki/HTTP#wiki-base-url

4

Hi Stéphane,

Thanks for answering.

Which version of Gatling do you use?

2.0.0-M3a (the latest at the time of this writing)

Which JDK?

java version “1.7.0”
Java™ SE Runtime Environment (build 1.7.0-b147)
Java HotSpot™ 64-Bit Server VM (build 21.0-b17, mixed mode)

What does your simulation look like? Do you have several users?

Here’s the scenario:

https://gist.github.com/fernandezpablo85/7344656

5

Hi Pablo,

I don’t see a reason why setting -Dsun.net.inetaddr.ttl=0 wouldn’t work.
Someone had an issue with Amazon ELB and it did fix the problem.

At this point, I advice you go with my previous suggestion and have Gatling do the round robin with baseUrls.

Cheers,

Stéphane