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To allow the TTL (Time to Live) of individual pages to vary while adhering to the maximum and minimum TTL settings configured for the Amazon CloudFront distribution, setting cache behaviors directly at the origin is most effective:Use Cache-Control Headers: By configuring the Cache-Control: max-age directive in the HTTP headers of the objects served from the origin, you can specify how long an object should be cached by CloudFront before it is considered stale.Integration with CloudFront: When CloudFront receives a request for an object, it checks the cache-control header to determine the TTL for that specific object. This allows individual objects to have their own TTL settings, as long as they are within the globally set minimum and maximum TTL values for the distribution.Operational Efficiency: This method does not require any additional AWS services or modifications to the distribution settings. It leverages HTTP standard practices, ensuring compatibility and ease of management.Implementing the TTL management through cache-control headers at the origin provides precise control over caching behavior, aligning with varying content freshness requirements without complex configurations.

# Enable instance scale-in protection for specific instance.aws autoscaling set-instance-protection --instance-ids i-5f2e8a0d --auto-scaling-group-name my-asg --protected-from-scale-in# Disable instance scale-in protection for the specified instance.aws autoscaling set-instance-protection --instance-ids i-5f2e8a0d --auto-scaling-group-name my-asg --no-protected-from-scale-inhttps://docs.aws.amazon.com/autoscaling/ec2/userguide/ec2-auto-scaling-instance-protection.htmlTo ensure that EC2 instances in an Auto Scaling group are not interrupted during message processing, the most effective method is to implement scale-in protection for the instances while they are actively processing messages. This can be done programmatically by modifying the Auto Scaling group's settings using the Amazon EC2 Auto Scaling API.Starting Message Processing: When an instance begins processing a message, your application should make an API call to enable scale-in protection. This is done using the SetInstanceProtection action, setting the ProtectedFromScaleIn parameter to true for that specific instance.Completing Message Processing: Once the message has been processed, another API call should be made to disable scale-in protection. This is done by calling the SetInstanceProtection action again, but this time setting the ProtectedFromScaleIn parameter to false.This method ensures that while messages are being processed, the instances are not terminated by the Auto Scaling group regardless of any scale-in activities that might be triggered by other parameters like CPU utilization or a decrease in the number of messages in the queue.AWS DocumentationReference: You can refer to the AWS documentation on managing instance scale-in protection in Auto Scaling groups for more details: Instance Scale-In Protection.

To effectively use Amazon CloudFront as a content delivery network for an application using an Application Load Balancer as the origin, several configuration steps need to be correctly implemented:DNS Configuration: Ensure that the DNS records for the domain serving the content point to the CloudFront distribution's DNS name rather than directly to the ALB. If the DNS still points to the ALB, users' requests will bypass CloudFront, leading directly to the ALB and maintaining the existing load on your web servers.TTL Settings: The Time to Live (TTL) settings in the CloudFront distribution dictate how long the content is cached in CloudFront edge locations before CloudFront fetches a fresh copy from the origin. If the TTL values are set to 0, it means that CloudFront does not cache the content at all, resulting in each user request being forwarded to the ALB, which does not reduce the load.AWS DocumentationReference: For more information on DNS and TTL configurations for CloudFront, you can refer to the following AWS documentation:Configuring DNSCloudFront TTL Settings.

AWS Systems Manager Run Command provides an efficient method to execute administrative tasks on EC2 instances. This solution will minimize the time and complexity involved:Select Document: Choose AWS-RunShellScript for Linux-based instances or AWS-RunPowerShellScript for Windows-based instances.Configure Command: Enter the mitigation script provided by the security team into the command document.Target Instances: Use the tagging system to target only the instances that match the specific OS as identified by their tags.Execute Command: Run the command across the targeted instances.Verification and Reporting: The command history in Systems Manager will serve as evidence of execution and success, which can be reported back to the security team. AWS DocumentationReference: More about Run Command can be found here: AWS Systems Manager Run Command.

This approach uses CloudWatch for monitoring and Lambda for automation, allowing for quick and efficient quota management:Setup CloudWatch Alarm: Monitor the usage of EC2 instances against the service quota using CloudWatch.Lambda Function: Write a Lambda function that triggers a quota increase request via the Service Quotas API when the threshold is met.Integration: Configure the CloudWatch alarm to trigger this Lambda function when the instance count approaches the service quota.AWS DocumentationReference: Information on monitoring with CloudWatch and automating actions with Lambda can be found in these guides: Amazon CloudWatch Alarms, AWS Lambda.

Using AWS CloudFormation stack sets allows you to manage CloudWatch alarms across multiple accounts efficiently:Create Stack Set: Use a CloudFormation template that defines the required CloudWatch alarms and configures them to publish alerts to an SNS topic.Specify SNS Topic: Ensure the SNS topic is located in the logging account and has the necessary permissions set to receive publications from all accounts in the organization.Deploy Across Organization: Implement the stack set across all accounts, ensuring centralized management and standardized deployment.AWS DocumentationReference: Learn more about deploying resources with CloudFormation StackSets: Working with AWS CloudFormation StackSets.

The requirement is to automate recovery if the service crashes on any of the EC2 instances.Option A: Install the Amazon CloudWatch agent on the EC2 instances. Configure the CloudWatch agent to monitor the service.Set the CloudWatch action to restart if the service health check fails .This is a valid solutionbecause the CloudWatch agent can be configured to monitor the service and take action (restart the service) if the health check fails .Option C: Tag the EC2 instances. Use AWS Systems Manager State Manager to create an association that uses the AWS-RunShellScript document. Configure the association command with a script that checks if the service isrunning and that starts the service if the service is not running. For targets, specify the EC2 instance tag.Schedule the association to run every 5 minutes678. This is a valid solution because AWS Systems Manager StateManager can be used to maintain a consistent state of the EC2 instances.It can run a script to check if the service is running and start the service if it's not running678.Option B: Tag the EC2 instances. Create an AWS Lambda function that uses AWS Systems Manager Session Manager to log in to the tagged EC2 instances and restart the service.Schedule the Lambda function to run every 5minutes . This is not a valid solution because AWS Lambda functions are not designed to log in to EC2 instances and restart services. They are used for running serverless applications.Option D: Update the EC2 user data that is specified in the Auto Scaling group's launch template to include a script that runs on a cron schedule every 5 minutes131415. This is not a valid solution because user data scripts arerun only during the launch of an EC2 instance. They are not designed to run on a schedule.Option E: Update the EC2 user data that is specified in the Auto Scaling group's launch template to ensure that the service runs during startup.Redeploy all the EC2 instances in the Auto Scaling group with the updated launchtemplate131416. This is not a valid solution because while user data can be used to ensure that the service runs during startup, it does not provide a solution for when the service crashes after the EC2 instance has started.

To route traffic based on the URL path during a transition period where both an EC2-based legacy application and a new AWS Lambda function are in use:Use of Application Load Balancer (ALB): ALBs support advanced request routing based on the URL path, among other criteria. This capability allows the ALB to evaluate the URL path of incoming requests and route them appropriately to either the legacy EC2 instances or the Lambda function.Path-Based Routing Rules: Configure the ALB with rules that specify which URL paths should be directed to the EC2 instances and which should be routed to the Lambda function. For example, requests to /legacy/* might go to the EC2 instances, while /new/* could be directed to the Lambda function.Integration with Lambda: ALBs can directly invoke Lambda functions in response to HTTP requests, making them ideal for scenarios where both server-based and serverless components are used in tandem.This setup not only facilitates a smooth transition by enabling simultaneous operation of both components but also leverages the native capabilities of ALBs to manage traffic based on application requirements effectively.