Saturday, August 03, 2019

Create VPC Subnet Security Group EC2 ELB using Python Boto3

This script assumes basic knowledge of AWS, Boto3 & Python.
Prerequisites:
  • AWS Account
  • IAM Role with Access & Secret Key
  • Boto3 Installed & Configured

- Install AWS CLI & Python Boto3 Library in Python using pip, which is package management tool written in Python.
# pip install awscli boto3

- Create user in AWS from AWS console and get the Secret Access Key & Access ID to access AWS services programatically.
# aws configure
- Run script using python command 
# python <script-name>.py

import boto3
import time

ec2 = boto3.resource('ec2')
client = boto3.client('ec2')

#Create VPC
response = client.create_vpc(CidrBlock='172.16.0.0/16',InstanceTenancy='default')

#Assign tags to VPC
client.create_tags(Resources=[response['Vpc']['VpcId']],Tags=[{'Key': 'Name','Value': 'my-drupal-vpc',}])

print('***** VPC Created with ID*********',response['Vpc']['VpcId'])
vpc_id = response['Vpc']['VpcId']

# Creating Internet Gateway for Drupal Web Instance subnets and attaching to VPC
ig = ec2.create_internet_gateway()
client.attach_internet_gateway(InternetGatewayId = ig.id, VpcId=vpc_id)

routetable1_response = client.create_route_table(VpcId=vpc_id)

def create_tag_for_route_table(route_table_number, route_table_name):
    tag = client.create_tags(Resources=[route_table_number['RouteTable']['RouteTableId']],Tags=[{'Key': 'Name','Value': route_table_name}])
    return tag

create_tag_for_route_table(routetable1_response,'drupal-rt1')
print('Route Table 1 Created - ',routetable1_response['RouteTable']['RouteTableId'])
route_table1 = ec2.RouteTable(routetable1_response['RouteTable']['RouteTableId'])

# Attach internet gateway to Routetable drupal-rt1 for web instances in subnet 1 and 3
route_table1.create_route(DestinationCidrBlock='0.0.0.0/0', GatewayId=ig.id)

# Attach internet gateway to Routetable drupal-rt1 for web instances in subnet 1 and 3
route_table1.create_route(DestinationCidrBlock='0.0.0.0/0', GatewayId=ig.id)

def create_subnet(cidr, vpc_id, azname):
        subnet_response = client.create_subnet(CidrBlock=cidr, VpcId=vpc_id, AvailabilityZone=azname)
        return subnet_response

def create_tag(subnet_number,subnet_name):
    client.create_tags(Resources=[subnet_number['Subnet']['SubnetId']], Tags=[{'Key': 'Name', 'Value': subnet_name}])

def modify_subnet_attribute(subnet_name):
    client.modify_subnet_attribute(MapPublicIpOnLaunch={'Value': True,}, SubnetId=subnet_name)

#Creating first subnet
subnet1 = create_subnet('172.16.1.0/24', vpc_id, 'us-east-1a')
ec2_subnet1 = subnet1['Subnet']['SubnetId']
create_tag(subnet1,'drupal-sb1-us-east-1a')
modify_subnet_attribute(ec2_subnet1)
print('Subnet 1 is Created with ID - ',ec2_subnet1)

#Associating Route Table 1 to Subnet 1
route_table1.associate_with_subnet(SubnetId=ec2_subnet1)
print('Route table 1 associated with Subnet 1 -',ec2_subnet1)

routetable2_response = client.create_route_table(VpcId=vpc_id)
create_tag_for_route_table('drupal-rt2')
print('Route Table 2 Created - ',routetable2_response['RouteTable']['RouteTableId'])
route_table2 = ec2.RouteTable(routetable2_response['RouteTable']['RouteTableId'])

# Creating second subnet
subnet2 = create_subnet('172.16.2.0/24', vpc_id, 'us-east-1a')
ec2_subnet2 = subnet2['Subnet']['SubnetId']
create_tag(subnet2,'drupal-sb2-us-east-1a')
print('Subnet 2 is Created with ID - ',ec2_subnet2)

#Associating Route Table 2 to Subnet 2
route_table2.associate_with_subnet(SubnetId=ec2_subnet2)
print('Route table 2 associated with Subnet 2 -',ec2_subnet2)

# Creating third subnet
subnet3 = create_subnet('172.16.3.0/24', vpc_id, 'us-east-1b')
ec2_subnet3 = subnet3['Subnet']['SubnetId']
create_tag(subnet3,'drupal-sb3-us-east-1b')
modify_subnet_attribute(ec2_subnet3)
print('Subnet 3 is Created with ID - ',ec2_subnet3)

#Associating Route Table 1 to Subnet 3
route_table1.associate_with_subnet(SubnetId=ec2_subnet3)
print('Route table 1 associated with Subnet 3 -',ec2_subnet3)

# Creating fourth subnet
subnet4 = create_subnet('172.16.4.0/24', vpc_id, 'us-east-1b')
ec2_subnet4 = subnet4['Subnet']['SubnetId']
create_tag(subnet4,'drupal-sb4-us-east-1b')
print('Subnet 4 is Created with ID - ',ec2_subnet4)

#Associating Route Table 2 to Subnet 4 
route_table2.associate_with_subnet(SubnetId=ec2_subnet4)
print('Route table 2 associated with Subnet 4 -',ec2_subnet4)

def create_security_group(descript, group_name):
    sg1_response = client.create_security_group(Description=descript,GroupName=group_name,VpcId=vpc_id)
    return sg1_response

def create_sg_tag(websg_or_elbsg,sg_group_name):
    sg_tag_response = client.create_tags(Resources=[websg_or_elbsg['GroupId']],Tags=[{'Key': 'Name','Value': sg_group_name}])
    return sg_tag_response

#Create Security Group for Drupal instances which will accept traffic from ALB
web_sg1 = create_security_group('Accept traffic from ALB', 'drupal-web-sg')
sgId = web_sg1['GroupId']
create_sg_tag(web_sg1,'drupal-web-sg')
print('Created Security Group for Web Instances -',sgId)

# Create Security for ALB which will accept traffic from Internet
elb_sg1 = create_security_group('Accept traffic from Internet','drupal-elb-sg')
elbsgId = elb_sg1['GroupId']
create_sg_tag(elb_sg1,'drupal-elb-sg')
print('Created Security Group for ELB -',elbsgId)

elb1 = ec2.SecurityGroup(elbsgId)
elb1.authorize_ingress(GroupId=elbsgId,IpPermissions=[{'IpProtocol': 'tcp', 'FromPort': 80, 'ToPort': 80, 'IpRanges': [{'CidrIp': '0.0.0.0/0'}]}])

client.authorize_security_group_ingress(GroupId=sgId, IpPermissions=[{'IpProtocol': '-1','UserIdGroupPairs': [{'GroupId': elbsgId}]}])

#Creating SSH key file for drupal instances
# create a file to store the key locally                                 
outfile = open('drupal-ec2-keypair.pem','w')                                                                                                      
# call the boto ec2 function to create a key pair                        
key_pair = ec2.create_key_pair(KeyName='drupal-ec2-keypair')             
# capture the key and store it in a file                                 
KeyPairOut = str(key_pair.key_material)                                    
outfile.write(KeyPairOut)  

# Creating instances for Drupal Infrastructure 
user_data_script = """#!/bin/bash
yum clean all
yum update -y
yum install httpd -y
echo "Hello this is drupal website" >> /var/www/html/index.html
systemctl start httpd
systemctl restart httpd
systemctl enable httpd"""

def create_instances(subnet_name, instance_name):
    web_instance = ec2.create_instances(ImageId='ami-011b3ccf1bd6db744',InstanceType='t2.micro',MinCount=1,MaxCount=1,KeyName='drupal-ec2-keypair',SubnetId=subnet_name,UserData=user_data_script,SecurityGroupIds=[sgId],TagSpecifications=[{'ResourceType': 'instance','Tags': [{'Key': 'Name','Value': instance_name}]}])
    return web_instance

web1_instance = create_instances(ec2_subnet1, 'drupal-web1')
time.sleep(60)
response1 = client.describe_instances()
for reservation in response1["Reservations"]:
     for instance in reservation["Instances"]:
        ec2 = boto3.resource('ec2')
        web1 = ec2.Instance(instance["InstanceId"])
print('Launching web1 instance - ',web1.id)

web2_instance = create_instances(ec2_subnet3, 'drupal-web2')
time.sleep(60)
response2 = client.describe_instances()
for reservation in response2["Reservations"]:
     for instance in reservation["Instances"]:
        ec2 = boto3.resource('ec2')
        web2 = ec2.Instance(instance["InstanceId"])
print('Launching web2 instance - ',web2.id)

# Application Load Balancer Code Starts here

lb = boto3.client('elbv2')
create_lb_response = lb.create_load_balancer(
    Name='drupal-web-elb',
    Subnets=[
        ec2_subnet1, ec2_subnet3,
    ],
    SecurityGroups=[
        elbsgId,
    ],
    Scheme='internet-facing',
    Tags=[
        {
            'Key': 'Name',
            'Value': 'drupal-web-elb'
        },
    ],
    Type='application',
    IpAddressType='ipv4'
)

lbId = create_lb_response['LoadBalancers'][0]['LoadBalancerArn']
print('Successfully created load balancer - ',lbId)

create_tg_response = lb.create_target_group(
    Name='drupal-web-tg',
    Protocol='HTTP',
    Port=80,
    TargetType='instance',
    HealthCheckPath='/index.html',
    VpcId=vpc_id
)
tgId = create_tg_response['TargetGroups'][0]['TargetGroupArn']
print('Successfully created target group - ',tgId)
#Create Listner for web elb
listnerId = lb.create_listener(
    LoadBalancerArn=lbId,
    Protocol='HTTP',
    Port=80,
    DefaultActions=[
        {
            'Type': 'forward',
            'TargetGroupArn': tgId
        },
    ]
)

# Register web instances with web-elb
regis_targets = lb.register_targets(TargetGroupArn=tgId,Targets=[{'Id': web1.id,},{'Id': web2.id}])

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