custodian metrics filters

metrics.rst

    Metrics Filters
    ---------------
    
    Supports cloud watch metrics filters on resources.                                                                                                                                                                                                                                                                                              
                                                                                                                                                                                                                                                                                                                                                       
    Docs on cloud watch metrics                                                                                                                                                                                                                                                                                                                        
                                                                                                                                                                                                                                                                                                                                                       
    - GetMetricStatistics - http://goo.gl/w8mMEY                                                                                                                                                                                                                                                                                                       
    - Supported Metrics - http://goo.gl/n0E0L7                                                                                                                                                                                                                                                                                                         
                                                                                                                                                                                                                                                                                                                                                       
    usage:: yaml                                                                                                                                                                                                                                                                                                                                       
                                                                                                                                                                                                                                                                                                                                                       
      - name: ec2-underutilized                                                                                                                                                                                                                                                                                                                        
        filters:                                                                                                                                                                                                                                                                                                                                       
          - type: metric                                                                                                                                                                                                                                                                                                                               
            name: CPUUtilization                                                                                                                                                                                                                                                                                                                       
            days: 4                                                                                                                                                                                                                                                                                                                                    
            period: 86400                                                                                                                                                                                                                                                                                                                              
            value: 30                                                                                                                                                                                                                                                                                                                                  
            op: less-than                                                                                                                                                                                                                                                                                                                              
                                                                                                                                                                                                                                                                                                                                                       
    Note periods when a resource is not sending metrics are not part                                                                                                                                                                                                                                                                                   
    of calculated statistics as in the case of a stopped ec2 instance,                                                                                                                                                                                                                                                                                 
    nor for resources to new to have existed the entire                                                                                                                                                                                                                                                                                                
    period. ie. being stopped for an ec2 intsance wouldn't lower the                                                                                                                                                                                                                                                                                   
    average cpu utilization,