Article Outline
Python mysql example 'manager'
Functions in program:
def get_db():def connect_to_database():
Modules used in program:
import mysql.connectorimport loggingimport timeimport boto3
python manager
Python mysql example: manager
import boto3
import time
import logging
import mysql.connector
from datetime import datetime, timedelta
from operator import itemgetter
'''
database config
'''
db_config = {'user': 'ece1779',
'password': 'secret',
'host': '127.0.0.1',
'database': 'project1_admin'}
'''
Functions for Database
'''
def connect_to_database():
return mysql.connector.connect(user=db_config['user'],
password=db_config['password'],
host=db_config['host'],
database=db_config['database'])
def get_db():
db = connect_to_database()
return db
'''
boto3 config
'''
ami_id = 'ami-26e84330'
ec2 = boto3.setup_default_session(region_name='us-east-1')
client = boto3.client('cloudwatch')
ec2 = boto3.resource('ec2')
metric_name = 'CPUUtilization'
namespace = 'AWS/EC2'
statistic = 'Average'
'''
Create Load Balancer
'''
elb = boto3.client('elb')
lb = elb.create_load_balancer(LoadBalancerName='myelb',
Listeners=[
{
'Protocol':'TCP',
'LoadBalancerPort':5000,
'InstanceProtocol':'TCP',
'InstancePort':5000
},
],
AvailabilityZones=['us-east-1a','us-east-1b','us-east-1c','us-east-1e']
)
# add worker security groups to load balancer
elb.apply_security_groups_to_load_balancer(LoadBalancerName='myelb',
SecurityGroups=['sg-e05d929f'])
# configure health check
health_check = elb.configure_health_check(LoadBalancerName='myelb',
HealthCheck={
'Target': 'TCP:5000',
'Timeout':2,
'Interval':5,
'UnhealthyThreshold':10,
'HealthyThreshold':2
}
)
# create the first worker
new_instance=ec2.create_instances(ImageId=ami_id,
KeyName='ece1779_project1',
MinCount=1,
MaxCount=1,
InstanceType='t2.small',
Monitoring={'Enabled': True},
# UserData =
SecurityGroupIds=[
'sg-e05d929f',
]
)
# attach the first worker instance to the lb
attachinst = elb.register_instances_with_load_balancer(LoadBalancerName='myelb',
Instances=[
{
'InstanceId':new_instance[0].id
}
])
#flag for booting up
flag = 1
num_of_instance_last_time = 0
while(1):
time.sleep(10)
# # wait for instance to boot up
# # check is there any pending worker instances
# flag = 0
# instances = ec2.instances.all()
# for instance in instances:
# if (instance.state['Name'] == 'pending'):
# print('Waiting for new instance to boot up......')
# # update the instance state
# flag = 1
# time.sleep(10)
# for status in ec2.meta.client.describe_instance_status()['InstanceStatuses']:
# if ((status['InstanceStatus']['Status']) != 'ok' or (status['SystemStatus']['Status']) != 'ok'):
# print('Waiting for new instance to register on the load balancer and pass the status check......')
# # update the instance state
# flag = 1
# time.sleep(10)
# if (flag == 1):
# continue
# compute the average cpu utilization now
instances = ec2.instances.filter(
Filters=[{'Name': 'instance.group-name', 'Values': ['worker_demo_security_group']}])
sum = 0.0
num_of_instance = 0
num_of_new_instance = 0
num_of_old_instance = 0
for instance in instances:
cpu = client.get_metric_statistics(
Period=1 * 60,
StartTime=datetime.utcnow() - timedelta(seconds=60 * 60),
EndTime=datetime.utcnow() - timedelta(seconds=0 * 60),
MetricName=metric_name,
Namespace=namespace, # Unit='Percent',
Statistics=[statistic],
Dimensions=[{'Name': 'InstanceId', 'Value': instance.id}]
)
datapoints = cpu['Datapoints']
if(datapoints!=[]):
last_datapoint = sorted(datapoints, key=itemgetter('Timestamp'))[-1]
print((last_datapoint))
utilization = last_datapoint['Average']
print((utilization))
sum = sum + utilization
num_of_instance = num_of_instance + 1
else:
continue
if(num_of_instance!=0):
utilization = sum / num_of_instance
else:
continue
if (num_of_instance_last_time==num_of_instance and flag==0):
continue
else:
flag = 1
num_of_instance_last_time = num_of_instance
# fetch the parameters from the database
cnx = get_db()
cursor = cnx.cursor()
query = '''SELECT * FROM config_parameters WHERE id =1
'''
cursor.execute(query)
parameters=cursor.fetchone()
if (parameters[3] != 1):
num_of_new_instance = num_of_instance * (parameters[3]-1)
# set back the database
query = '''UPDATE config_parameters
SET expandratio = 1
WHERE id = 1
'''
cursor.execute(query)
cnx.commit()
if (parameters[4] != 1):
num_of_old_instance = num_of_instance * (parameters[4]-1)/(parameters[4])
# set back the database
query = '''UPDATE config_parameters
SET shrinkratio = 1
WHERE id = 1
'''
cursor.execute(query)
cnx.commit()
if(utilization>parameters[1]):
num_of_new_instance = num_of_new_instance + 1
flag = 0
if(utilization<parameters[2]):
num_of_old_instance = num_of_old_instance + 1
flag = 0
if (num_of_new_instance!=0):
for i in range(num_of_new_instance):
new_instance = ec2.create_instances(ImageId=ami_id,
KeyName='ece1779_project1',
MinCount=1,
MaxCount=1,
InstanceType='t2.small',
Monitoring={'Enabled': True},
SecurityGroupIds=[
'sg-e05d929f',
]
)
attachinst = elb.register_instances_with_load_balancer(LoadBalancerName='myelb',
Instances=[
{
'InstanceId': new_instance[0].id
}
])
if (num_of_old_instance!=0):
instances = ec2.instances.filter(
Filters=[{'Name': 'instance-state-name', 'Values': ['running']}])
instances = ec2.instances.filter(
Filters=[{'Name':'instance.group-name', 'Values':['worker_demo_security_group']}]
)
i=0
for instance in instances:
elb.deregister_instances_from_load_balancer(LoadBalancerName='myelb',
Instances=[
{
'InstanceId': instance.id
}
])
instance.terminate()
i=i+1
if (i >= num_of_old_instance):
break
# delete load balancer
# elb.delete_load_balancer(LoadBalancerName='myelb')
Python links
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