AWS Ruby CloudWatch API returns nothing

Question

I want to use CloudWatch to get CPU usage from the instanced created in the same program. mon-get-stats could get the metric from the instance id I specified. But when I use Ruby AWS API as below, it returns nothing. I have tried some methods in other website, but none works.

Any suggestion about this issue? Thanks in advance!

 metric = AWS::CloudWatch::Metric.new( 'AWS/EC2', 'CPUUtilization',
      :dimensions => [{ :name => 'InstanceID', :value => 'i-63be8f06' }])
 stats = metric.statistics(
 :start_time => '2013-09-21T17:01:00',
 :end_time => '2013-09-21T17:11:00',
 :period => 60,
 :statistics => ['Average'])

 stats.each do |datapoint|
   puts datapoint
 end

Answer 1

You are querying :period => 60 .. is it definitely a 1minute metric ? .. do you have detailed monitoring enabled for that instance ? ..

Try your query with :period => 300 and see if you get any data back (i.e query for 5 min)