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Created February 16, 2012 00:56
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Get CloudWatch metrics for Amazon EBS volumes
# Get Cloudwatch metrics for the EBS volumes attached to an instance
import datetime
import logging
import sys
import urllib
import boto
from boto.exception import BotoServerError, EC2ResponseError
from boto.ec2.connection import EC2Connection
class InstanceDimension(dict):
Helper class for get_metric_statistics call
def __init__(self, name, value):
self[name] = value
class EBSStatsCollector(object):
Retrieve EBS stats for a given instance
Amazon metrics to retrieve for each volume
def __init__(self, minutes=60, period=60):
@param minutes: int, minutes to look back
@param period: int, sample bucket size in seconds
self._cloudwatch = boto.connect_cloudwatch()
self._connection = EC2Connection()
self._minutes = minutes
self._period = period
def get_volume_stats(self, volume_id):
Get stats for a particular EBS volume
@param volume_id: string, EBS volume identifier
@return: dict, metric -> value dict
ret = {}
for metric in self.METRICS:
end = datetime.datetime.utcnow()
start = end - datetime.timedelta(minutes=self._minutes)
stats = self._cloudwatch.get_metric_statistics(self._period, start, end, metric,
'AWS/EBS', 'Average',
InstanceDimension("VolumeId", volume_id)
if not stats:
logging.warning('Could not get %s for volume %s (or metric is empty)', metric, volume_id)
ret[metric] = stats[0][u'Average']
except BotoServerError, error:
logging.warning('Boto API error: %s', error)
ret[metric] = 0
return ret
def get_all_stats(self, instance_id):
Get CloudWatch statistics for the EBS volumes attached to a given instance
API docs:
Hint: to figure out the exact params, use the AWS console and look
at the query params when clicking on cloudwatch metrics...
@param instance: string, instance to get information for
volumes = self.get_instance_volumes(instance_id)
for (mount, volume) in volumes.items():
print '%s (%s):' % (mount,
stats = self.get_volume_stats(
print '\t', stats
def get_all_stats_localhost(self):
Get CloudWatch statistics for the EBS volumes attached to localhost.
return self.get_all_stats(self.get_instance_id())
def get_instance(self, instance_id):
Return an Instance object for the given instance id
@param instance_id: Instance id (string)
@return: Instance object, or None if not found
reservations = self._connection.get_all_instances([instance_id])
except EC2ResponseError, ex:
logging.warning('Got exception when calling EC2 for instance "%s": %s',
instance_id, ex.error_message)
return None
for r in reservations:
if len(r.instances) and r.instances[0].id == instance_id:
return r.instances[0]
return None
def get_instance_volumes(self, instance_id):
Returns volumes for a specific instance as a map of mount device to volume
@param instance_id: string, instance id
@return: dict, mount -> volume
instance = self.get_instance(instance_id)
devices = instance.block_device_mapping
if not devices:
return {}
ebs_info = {}
vs = self._connection.get_all_volumes()
volumes = {}
for volume in vs:
volumes[] = volume
for mount, device in devices.items():
ebs_info[mount] = volumes[device.volume_id]
return ebs_info
def get_instance_id(self):
Retrieve the Amazon instance id of the instance we are running on.
@return: string, instance id
return urllib.urlopen('').read()
if __name__ == "__main__":
collector = EBSStatsCollector()
if len(sys.argv) == 2:
# Argument is instance id
# Default to localhost
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@neil, @inGI

Does "Kind of Instance" refers to either "dev", "staging" or "prod" environment and extend the volume accordingly?
As per the description of the user story, we need to create a script which will trigger a CloudWatch event to monitor the EBS volumes and in-turn it should call SSM document to perform an EBS volume extension if required.

Please correct if we are missing out something.

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