Selecting services to develop deployment strategies and implement appropriate rollback mechanisms

What AWS service would you primarily use to implement a blue/green deployment strategy?

AWS Elastic Beanstalk or Amazon ECS (Elastic Container Service) would be the primary services to implement a blue/green deployment strategy. AWS Elastic Beanstalk directly supports blue/green deployments by allowing you to deploy a new version of your application to a separate environment and then swap CNAMEs of the original and new environments once you are satisfied with the new version. Amazon ECS can be configured to use blue/green deployments via integration with AWS CodeDeploy, which handles the deployment orchestration.

When deploying a new application version in AWS, which service can automatically handle the rollback upon detecting deployment failures?

AWS CodeDeploy can be configured to automatically roll back deployments if predefined deployment rules (like CloudWatch alarms) are triggered. This helps ensure minimal disruption if a new deployment has issues.

How can AWS CloudFormation help in implementing rollback strategies during the infrastructure deployment?

AWS CloudFormation supports automatic rollback on error, which means if any resource fails to create or update, the entire stack rolls back to the previous stable state. You can define rollback triggers and use stack policies to prevent accidental updates.

How would you ensure zero downtime during deployments for a highly available web application in AWS?

Ensure zero downtime by using a combination of Auto Scaling, Elastic Load Balancing, and deployment strategies such as rolling updates or blue/green deployments. Rolling updates gradually replace instances with new ones, while blue/green deployments shift traffic to a completely new, parallel environment before decommissioning the old one.

Can using Amazon Route 53 assist with rollback strategies? If so, how?

Yes, Amazon Route 53 can assist with rollback strategies by allowing weighted routing policies, where different amounts of traffic are directed to different endpoints. If a new deployment needs to be rolled back, adjusting the weights can redirect traffic back to the original endpoints quickly.

Describe how you would use AWS Lambda to implement a custom rollback mechanism for an infrastructure deployment?

AWS Lambda can be used to create custom functions that are triggered in response to various AWS events, including CloudFormation stack updates. A custom Lambda function can programmatically detect when a stack update isn’t going as planned (via CloudWatch events or logs), and initiate a rollback by executing specific AWS API calls to revert to previous resource configurations.

What are some of the considerations when selecting a rollback strategy for a stateful application in AWS?

For stateful applications, rollback strategies need to consider data consistency and integrity. This means ensuring database schema changes are backward compatible, leveraging services like Amazon RDS with multi-AZ deployments for redundancy, and considering Data Migration Service (DMS) for seamless data replication. Snapshots and point-in-time recovery are also important considerations.

When implementing a canary deployment strategy on AWS, which services facilitate this approach?

AWS CodeDeploy, in conjunction with Amazon API Gateway and AWS Lambda, is suitable for implementing canary deployments. AWS CodeDeploy allows you to release the new application incrementally to a subset of instances and then monitor performance and errors before a wider rollout.

What AWS feature allows you to safely implement deployment and rollback strategies for AWS Lambda-based applications?

AWS Lambda supports versioning and aliases, with the capability to route traffic between different versions of a Lambda function. By using these features, you can safely deploy new function versions, initiate canary release, and rollback if necessary by changing the alias to point back to the stable version.

How would you utilize Amazon S3’s versioning feature in your deployment strategy for rollback capabilities?

Amazon S3 versioning can maintain multiple versions of an object in a bucket, which can be integral to a deployment strategy. In case of a failed deployment or need to rollback, you can use versioning to quickly restore previous object versions, which is especially useful for configuration files, Lambda deployment packages, and static web content.

In the context of deploying microservices on AWS ECS, what is the significance of service discovery in successful rollbacks?

Service discovery is critical in a microservices architecture as it allows microservices to dynamically discover and communicate with each other. AWS Cloud Map or third-party tools can facilitate this. In the event of a rollback, service discovery ensures that requests are correctly routed to the stable versions of services, even as instances are added or removed during rollback processes.

How would AWS Backup assist in providing a rollback option for data-centric deployments?

AWS Backup enables you to create automated and on-demand backups of various AWS services, including EBS volumes, RDS databases, and DynamoDB tables. In the context of a rollback, AWS Backup can be used to restore data from a known good state, which is critical for recovering from accidental data loss or corruption due to problematic deployments.