Amazon Autoscaling trigger not working, how do I debug it?

Question

I'm trying to use autoscaling to create new EC2 instances whenever average CPU load on existing instances goes high. Here's the situation:

• I'm setting up autoscaling using this boto script (with keys and image names removed). http://balti.ukcod.org.uk/~francis/tmp/start_scaling_ptdaemon.nokeys.py

• I've got min_size set to 2, and the AutoScalingGroup correctly creates an initial 2 instances, which both work fine. I'm pretty sure this means the LaunchConfiguration is right.

• When load goes up to nearly 100% on both those two instances, nothing happens.

Some questions / thoughts:

• Is there any way of debugging this? I can't find any API calls that give me detals of what Autoscaling is doing, or thinks it is doing. Are there any tools that give feedback either on what it is doing, or on whether it has set things up correctly?

• It would be awesome if Autoscaling appeared in the AWS Console.

• I'm using EU west availability zone. Is there any reason that should cause trouble with Autoscaling?

• Is there any documentation of the "dimensions" parameter when creating a trigger? I have no idea what it means, and have just copied its fields from an example. I can't find any documentation about it that doesn't self-referentially say it is a "dimension", without explaining what that means or what the possible values are.

Thanks for any help!

Answer 1

I'm sure you've already found these and it would be good to use AWS tool first before the Python tool to get the idea.:)

http://ec2-downloads.s3.amazonaws.com/AutoScaling-2009-05-15.zip http://docs.amazonwebservices.com/AutoScaling/latest/DeveloperGuide/

Cheers,

Rodney

Answer 2

Also, take a look at something like http://alestic.com/2011/11/ec2-schedule-instance for a simple example of how to use the tools with a demo script provided.