In an e-commerce company’s AWS setup, there’s a three-tier application: a web front end, a backend application, and a database storing transactions and user data. The database currently runs on an extra-large instance with 128 GB of memory.
To meet the company’s disaster recovery requirements:
- Achieve a fast Recovery Time Objective (RTO) of 5 minutes.
- Maintain a Recovery Point Objective (RPO) of 1 hour.
- Keep the backup site at least 250 miles away from the primary site.
What solution should the Solutions Architect implement to meet these requirements while minimizing costs?
Solution
1. Create a Standby Database Instance:
# Create an RDS Read Replica (standby) in the backup region
aws rds create-db-instance-read-replica --db-instance-identifier your-primary-db-instance-identifier \
--db-instance-identifier your-standby-db-instance-identifier --region backup-region
2. Set Up EC2 Instances in the Backup Region:
# Launch EC2 instances for the web and application servers
# Using an Auto Scaling group is recommended for scalability and fault tolerance
aws ec2 run-instances --image-id your-ami-id --count 1 --instance-type your-instance-type \
--key-name your-key-pair-name --security-group-ids your-security-group-ids --subnet-id your-subnet-id \
--region backup-region
# Create an Auto Scaling group for the web server
aws autoscaling create-auto-scaling-group --auto-scaling-group-name web-asg \
--launch-configuration-name web-launch-config --min-size 1 --max-size 5 --desired-capacity 1 \
--availability-zones backup-region-az
# Create an Auto Scaling group for the application server
aws autoscaling create-auto-scaling-group --auto-scaling-group-name app-asg \
--launch-configuration-name app-launch-config --min-size 1 --max-size 5 --desired-capacity 1 \
--availability-zones backup-region-az
3. Configure an Application Load Balancer (ALB):
# Create an Application Load Balancer
aws elbv2 create-load-balancer --name your-alb-name --subnets your-subnet-ids --scheme internet-facing --region backup-region
4. Add EC2 Instances to the ALB Target Groups:
# Create a target group for the web server instances
aws elbv2 create-target-group --name web-target-group --protocol HTTP --port 80 --vpc-id your-vpc-id --region backup-region
# Create a target group for the application server instances
aws elbv2 create-target-group --name app-target-group --protocol HTTP --port 8080 --vpc-id your-vpc-id --region backup-region
# Register instances to the target groups
aws elbv2 register-targets --target-group-arn your-web-target-group-arn --targets Id=i-1234567890abcdef0 --region backup-region
aws elbv2 register-targets --target-group-arn your-app-target-group-arn --targets Id=i-1234567890abcdef1 --region backup-region
5. Set Up Amazon Route 53 for Failover:
# Create a Route 53 record with a failover routing policy
aws route53 create-health-check --caller-reference your-health-check-reference --health-check-config FailureThreshold=3,IPAddress=your-alb-dns-name,Port=80,Type=HTTP --region backup-region
# Create a Route 53 record set
aws route53 create-traffic-policy-instance --traffic-policy-instance-name your-traffic-policy-instance-name --traffic-policy-id your-traffic-policy-id --comment "Failover policy" --name your-route53-record-name --type A --set-identifier primary --failover PRIMARY --health-check-id your-health-check-id --region backup-region
# Update the Route 53 record set to point to the primary or backup region as needed
aws route53 update-traffic-policy-instance --id your-traffic-policy-instance-id --hosted-zone-id your-hosted-zone-id --region backup-region
6. Scale EC2 Instances for Demand:
To scale the instances in case of a disaster, use the autoscaling set-desired-capacity
command to update the desired capacity of your Auto Scaling groups.
# Example: Scale the web server Auto Scaling group to 3 instances
aws autoscaling set-desired-capacity --auto-scaling-group-name web-asg --desired-capacity 3 --region backup-region
# Example: Scale the application server Auto Scaling group to 2 instances
aws autoscaling set-desired-capacity --auto-scaling-group-name app-asg --desired-capacity 2 --region backup-region
This set of AWS CLI commands helps you implement a disaster recovery solution with a standby database, EC2 instances behind Application Load Balancers, and Route 53 DNS failover for your e-commerce application. Please make sure to replace the placeholder values with your actual resource identifiers and configuration details.
Solution using boto3
To implement the disaster recovery solution described in your scenario using Python and Boto3 (the AWS SDK for Python), you can follow these steps. First, ensure that you have the Boto3 library installed and properly configured with your AWS credentials.
Here’s how to implement the solution using Boto3:
import boto3
# Initialize the AWS clients for different services
ec2_client = boto3.client('ec2', region_name='backup-region')
rds_client = boto3.client('rds', region_name='backup-region')
elbv2_client = boto3.client('elbv2', region_name='backup-region')
autoscaling_client = boto3.client('autoscaling', region_name='backup-region')
route53_client = boto3.client('route53', region_name='backup-region')
# 1. Create a Standby Database Instance
rds_client.create_db_instance_read_replica(
SourceDBInstanceIdentifier='your-primary-db-instance-identifier',
DBInstanceIdentifier='your-standby-db-instance-identifier'
)
# 2. Set Up EC2 Instances in the Backup Region
ec2_client.run_instances(
ImageId='your-ami-id',
MinCount=1,
MaxCount=1,
InstanceType='your-instance-type',
KeyName='your-key-pair-name',
SecurityGroupIds=['your-security-group-ids'],
SubnetId='your-subnet-id'
)
# 3. Configure an Application Load Balancer (ALB)
elbv2_client.create_load_balancer(
Name='your-alb-name',
Subnets=['your-subnet-ids'],
Scheme='internet-facing'
)
# 4. Add EC2 Instances to ALB Target Groups
web_target_group = elbv2_client.create_target_group(
Name='web-target-group',
Protocol='HTTP',
Port=80,
VpcId='your-vpc-id'
)
app_target_group = elbv2_client.create_target_group(
Name='app-target-group',
Protocol='HTTP',
Port=8080,
VpcId='your-vpc-id'
)
# Register instances to the target groups
ec2_client.register_targets(
TargetGroupArn=web_target_group['TargetGroups'][0]['TargetGroupArn'],
Targets=[{'Id': 'i-1234567890abcdef0'}]
)
ec2_client.register_targets(
TargetGroupArn=app_target_group['TargetGroups'][0]['TargetGroupArn'],
Targets=[{'Id': 'i-1234567890abcdef1'}]
)
# 5. Set Up Amazon Route 53 for Failover
health_check = route53_client.create_health_check(
CallerReference='your-health-check-reference',
HealthCheckConfig={
'FailureThreshold': 3,
'IPAddress': 'your-alb-dns-name',
'Port': 80,
'Type': 'HTTP'
}
)
traffic_policy_instance = route53_client.create_traffic_policy_instance(
TrafficPolicyInstanceId='your-traffic-policy-instance-name',
HostedZoneId='your-hosted-zone-id',
TrafficPolicyId='your-traffic-policy-id',
Comment='Failover policy',
Name='your-route53-record-name',
Type='A',
SetIdentifier='primary',
Failover='PRIMARY',
HealthCheckId=health_check['HealthCheck']['Id']
)
# 6. Scale EC2 Instances for Demand
# Use the Boto3 Auto Scaling API to scale your instances as needed
# Example: Scale the web server Auto Scaling group to 3 instances
autoscaling_client.set_desired_capacity(
AutoScalingGroupName='web-asg',
DesiredCapacity=3
)
# Example: Scale the application server Auto Scaling group to 2 instances
autoscaling_client.set_desired_capacity(
AutoScalingGroupName='app-asg',
DesiredCapacity=2
)
Make sure to replace the placeholder values in the code with your actual resource identifiers and configuration details.
This Python script uses Boto3 to automate the creation and configuration of the components for your disaster recovery solution.