Tutorial / Cram Notes

Event-driven infrastructure refers to the practice of automatically changing configurations in response to specific triggers or events. These events could include changes in network traffic, application state, system health, or other metrics. The idea is to enable a system that is self-healing, scalable, and adaptive to varying loads and potential disruptions.

AWS Services for Event-Driven Infrastructure

AWS offers several services that help in altering infrastructure configurations based on events:

  • AWS CloudWatch: Monitors AWS resources and applications, allowing the collection and tracking of metrics, collection and monitoring of log files, and setting alarms.
  • AWS Lambda: Provides a compute service that lets you run code in response to events and automatically manage the underlying compute resources.
  • Amazon SNS: A flexible, fully managed pub/sub messaging and mobile notifications service for coordinating the delivery of messages to subscribing endpoints and clients.
  • AWS CloudFormation: Allows you to model and set up your AWS resources so that you can spend less time managing those resources and more time focusing on your applications.

Use Case Scenarios

Auto-Scaling Based on Traffic

One common scenario is scaling an application’s infrastructure to meet demand. AWS Auto Scaling and Elastic Load Balancing (ELB) work together with CloudWatch to automatically adjust the number of EC2 instances in response to traffic.

For example, if the CPU utilization of your EC2 instances goes above 70% for several minutes, CloudWatch can trigger an event. This event can initiate an Auto Scaling action to launch additional EC2 instances to distribute the load more evenly.

Automated Backups and Snapshots

Another example is the automated backup of data when specific conditions are reached. Using AWS Lambda in conjunction with Amazon CloudWatch Events, you can trigger Lambda functions to create snapshots of EBS volumes periodically or when a certain event like an instance-state-change occurs.

Infrastructure Updates Based on Code Commits

With AWS CodePipeline and Lambda, you can deploy updates to your infrastructure as soon as code is committed to a repository. In this scenario, a Lambda function could be triggered to run AWS CloudFormation, which would update the infrastructure as per the changes in the AWS CodeCommit repository.

Infrastructure as Code (IaC)

Infrastructure as Code (IaC) is also a critical component when it comes to modifying infrastructure configurations. AWS CloudFormation allows you to use a template file to define your AWS infrastructure, and change sets allow you to see how changes will impact your services before implementation.

For example, suppose you wanted to update the instance type of an Auto Scaling group. You would update the corresponding CloudFormation template and apply this update. CloudFormation would calculate the change set and apply these changes accordingly.

Resources:
MyAutoScalingGroup:
Type: AWS::AutoScaling::AutoScalingGroup
Properties:

LaunchConfigurationName: !Ref MyLaunchConfig
MinSize: ‘1’
MaxSize: ‘4’
DesiredCapacity: ‘2’

MyLaunchConfig:
Type: AWS::AutoScaling::LaunchConfiguration
Properties:

InstanceType: t3.large # Update this line to modify the instance type.

When you apply this modified template, the Auto Scaling group’s instances will gradually be updated to the new instance type during a rolling update.

Conclusion

When preparing for the AWS Certified DevOps Engineer – Professional (DOP-C02) exam, understanding how to effectively modify infrastructure configurations in response to events is vital. By leveraging AWS services such as CloudWatch, Lambda, SNS, Auto Scaling, and CloudFormation, you can create a robust and responsive infrastructure that adjusts automatically to the conditions defined by your operational policies. Mastery of these tools and concepts will not only help you pass the certification exam but also enable you to architect and manage AWS-based infrastructures proficiently.

Practice Test with Explanation

True or False: AWS CloudFormation cannot be used to update existing infrastructure in response to events.

  • Answer: False

Explanation: AWS CloudFormation provides a way to create and manage a collection of resources, and it can be used to update existing infrastructure when changes to the CloudFormation template are made.

You can automate responses to AWS CloudWatch alarms by triggering:

  • A. AWS Lambda functions
  • B. SNS notifications
  • C. EC2 Auto Scaling policies
  • D. All of the above

Answer: D

Explanation: AWS CloudWatch alarms can trigger various actions including AWS Lambda functions, SNS notifications, and EC2 Auto Scaling policies to respond automatically to changing conditions.

True or False: AWS CodeDeploy can be used to automate the deployment of applications, but it cannot modify the underlying infrastructure configurations.

  • Answer: True

Explanation: AWS CodeDeploy automates application deployments to various compute services such as Amazon EC2, AWS Fargate, and AWS Lambda. It does not modify the underlying infrastructure configurations.

Which AWS service enables you to define, manage, and automate infrastructure provisioning through code?

  • A. AWS CodeBuild
  • B. AWS CloudFormation
  • C. AWS CodePipeline
  • D. Amazon EC2

Answer: B

Explanation: AWS CloudFormation allows you to use programming languages or a simple text file to model and provision, in an automated and secure manner, all the resources needed for your applications across all regions and accounts.

An Amazon EC2 instance scaling action is an appropriate response to:

  • A. A high memory utilization alarm
  • B. A high CPU utilization alarm
  • C. A change in the application version
  • D. Both A and B

Answer: D

Explanation: High memory or CPU utilization alarms can trigger an EC2 instance scaling action as a response to ensure that the application meets its performance requirements.

True or False: AWS Elastic Beanstalk can monitor application health and automatically handle the details of capacity provisioning, load balancing, scaling, and application deployment.

  • Answer: True

Explanation: AWS Elastic Beanstalk automatically handles the deployment details such as capacity provisioning, load balancing, auto-scaling, and application health monitoring.

AWS Systems Manager allows you to:

  • A. Automatically update security groups based on threat intelligence
  • B. Automatically apply OS patches
  • C. Automatically create new EC2 instances during a scaling event
  • D. Automatically adjust Amazon RDS instances

Answer: B

Explanation: AWS Systems Manager provides visibility and control of the infrastructure on AWS and can automatically apply OS patches to maintain security and compliance.

True or False: Amazon SNS and AWS Lambda can be used together to automatically update DNS records in Amazon Route 53 in response to an event.

  • Answer: True

Explanation: Amazon SNS can trigger an AWS Lambda function, which can then run code to update DNS records in Amazon Route

Which AWS feature can be used to change the configuration of Amazon EC2 instances based on real-time demand?

  • A. AWS Auto Scaling
  • B. AWS Config
  • C. Amazon Inspector
  • D. AWS CloudTrail

Answer: A

Explanation: AWS Auto Scaling helps you maintain application availability and allows you to automatically scale your Amazon EC2 capacity up or down according to conditions you define.

True or False: An AWS Lambda function can be invoked as a target for an Amazon S3 event notification.

  • Answer: True

Explanation: An AWS Lambda function can be set as a target for Amazon S3 event notifications to trigger automated actions when objects are created, updated, or deleted in an S3 bucket.

Which of the following is NOT a suitable method for modifying infrastructure configurations in AWS?

  • A. Editing security group rules manually in response to a security incident
  • B. Using AWS OpsWorks Stacks to deploy and manage applications
  • C. Invoking an AWS Lambda function in response to Amazon CloudWatch Logs data
  • D. Manually resizing an Amazon RDS instance through the AWS Management Console

Answer: A

Explanation: While you can edit security group rules manually, it is not a scalable or suitable method for modifying infrastructure configurations in response to events in an automated and repeatable manner, which is the focus of AWS DevOps practices.

True or False: AWS Config rules can trigger AWS Systems Manager Automation documents to remediate non-compliant resources.

  • Answer: True

Explanation: AWS Config rules can be used to evaluate the configuration of AWS resources, and when a resource is found to be non-compliant, AWS Config can trigger an AWS Systems Manager Automation document to remediate the issue.

Interview Questions

Can you explain how AWS CloudFormation can be used to automatically respond to infrastructure events and modify configurations?

AWS CloudFormation can be integrated with AWS Lambda to respond to infrastructure events. You can use AWS Lambda custom resources in your CloudFormation templates to execute custom logic when stack events occur, such as creating, updating, or deleting resources. Additionally, using CloudFormation’s intrinsic functions and mappings, you can update stack templates and adapt configurations based on specific events or conditions.

How does Amazon CloudWatch Events help in modifying infrastructure in response to system events?

Amazon CloudWatch Events can detect changes in your AWS resources and trigger automated actions in response. By creating rules that match specific events, you can have CloudWatch Events invoke AWS Lambda functions, put messages to Amazon SNS topics, or perform various other actions defined in the rule. These actions can include modifying infrastructure configurations.

What role does AWS Lambda play in modifying infrastructure configurations in an event-driven architecture?

AWS Lambda plays a central role in event-driven architectures by providing a platform to run code in response to events. For instance, when a specific event is detected, such as a change in load or an update to an Amazon S3 bucket, a Lambda function can be triggered to programmatically modify infrastructure configurations through AWS SDK or AWS CLI commands, without requiring server provisioning or management.

Describe how AWS Config can be utilized to automate infrastructure configuration changes in response to compliance rule violations.

AWS Config continuously monitors and records your AWS resource configurations, allowing you to assess, audit, and evaluate configurations. If AWS Config detects a configuration change that violates a compliance rule, you can set up AWS Config rules to trigger an AWS Lambda function to automatically remediate the configuration and bring it back into compliance.

What is Amazon EventBridge, and how can it be used to modify infrastructure in response to events?

Amazon EventBridge is a serverless event bus that connects application data from your apps, integrated SaaS applications, and AWS services. It can route events to targets like AWS Lambda, enabling automated modification of infrastructure configurations. For example, it can trigger a Lambda function to update an Auto Scaling policy based on an event indicating a spike in traffic.

How does AWS Systems Manager help in dynamically managing the configuration of your infrastructure?

AWS Systems Manager provides visibility and control over your infrastructure on AWS. It allows you to automate operational tasks to help make your system more consistent, compliant, and secure. For example, Systems Manager can automatically apply OS patches, update software, or change environment variables across your instances in response to specific triggers or on a scheduled basis.

Can you demonstrate a scenario where the AWS Step Functions service would be utilized to modify infrastructure configurations in response to a sequence of events?

AWS Step Functions coordinate multiple AWS services into serverless workflows. In a scenario where multiple sequential steps are needed to modify infrastructure configurations, such as a multi-tier deployment or a database migration, Step Functions can orchestrate the different tasks (like Lambda functions, API calls to AWS services, or manual approvals) needed to perform the configuration changes, ensuring that each step is executed in the correct order and handling error cases smoothly.

How would you use AWS Elastic Beanstalk to automatically handle infrastructure configuration changes due to varying application load?

AWS Elastic Beanstalk automatically scales your application up and down based on defined conditions such as CPU utilization or network traffic. You can configure these scaling conditions through the Elastic Beanstalk management console or using configuration files. Beanstalk will then modify the infrastructure configurations, such as adjusting the number of EC2 instances, to match the demand without manual intervention.

Explain how you can use AWS CodeDeploy to manage infrastructure modifications caused by new application versions that may have different resource requirements.

AWS CodeDeploy can deploy application updates across your instances and handle any necessary changes in the infrastructure configuration as part of the deployment process. For example, if a new application version requires more compute resources, CodeDeploy can modify Auto Scaling groups or EC2 instances to meet the new requirements as it deploys the updated code using appspec.yml files to define the necessary hooks and tasks.

What are AWS Auto Scaling policies and how can they be used to modify EC2 instance configurations in response to changing performance metrics?

AWS Auto Scaling policies define how an EC2 fleet should automatically adjust its capacity to maintain steady, predictable performance. They can automatically change the EC2 instances configuration, such as the number of instances, in response to changing performance metrics like CPU utilization, network input/output, or custom CloudWatch metrics. Dynamic scaling policies, for instance, modify the instance count proportionally to a predefined metric, ensuring that the infrastructure scales according to workload demands.

0 0 votes
Article Rating
Subscribe
Notify of
guest
27 Comments
Oldest
Newest Most Voted
Inline Feedbacks
View all comments
Ingvild Skogsrud
7 months ago

Great post on modifying infrastructure configurations in response to different events. Very helpful for the AWS Certified DevOps Engineer (DOP-C02) exam.

Esteban Peña
6 months ago

Can someone explain the best practices for using AWS CloudFormation with CodePipeline for infrastructure modifications during an event?

سام سهيلي راد

Thank you for this detailed tutorial. It really simplifies the complexities involved in infrastructure configuration management.

Osman Rinke
7 months ago

How do you handle rollback scenarios for infrastructure changes in AWS?

Çetin Önür
7 months ago

Just passed the AWS Certified DevOps Engineer (DOP-C02) exam! This blog was really useful.

Corina Reitz
7 months ago

What’s the role of AWS Lambda in modifying infrastructure configurations during events?

Liam Moore
5 months ago

Couldn’t agree more, this blog is a goldmine of information. Thanks!

Henner Niehoff
7 months ago

I think the section on IAM roles could use more detail.

27
0
Would love your thoughts, please comment.x
()
x