Amazon Web Services Updated SOA-C02 Exam Questions and Answers by katie

To set up a notification for failed health checks of targets in the ALB, follow these steps:

Create a CloudWatch Alarm:

Navigate to CloudWatch and create a new alarm based on the UnHealthyHostCount metric of the target group.

In AWS, there are default limits (also known as quotas) for the number of various resources that can be created in an account. One of these limits is the number of Virtual Private Clouds (VPCs) that can be created in a single AWS account within a Region. The default limit for the number of VPCs per account per Region is typically 5.

If an organization is running multiple applications, each requiring a new VPC, it is possible to reach this limit, causing subsequent CloudFormation stack deployments that attempt to create additional VPCs to fail.

Check VPC Limits:

To verify the current limit and usage of VPCs in your account, you can use the AWS Service Quotas console.

Open the Service Quotas console at Service Quotas Console.

Navigate to AWS services and select Amazon VPC.

Check the VPCs per Region quota to see the limit and how many VPCs are currently in use.

Requesting a Quota Increase:

If the default limit is reached, you can request a quota increase.

In the Service Quotas console, select the quota and choose Request quota increase.

Fill in the required information and submit the request. AWS typically reviews and approves these requests, but it may take some time.

CloudFormation Stack Failure:

When a CloudFormation stack fails due to reaching the VPC limit, the error message will indicate the issue related to the quota being exceeded.

You can view the specific error in the CloudFormation console under the Events tab of the stack.

Preventative Measures:

To avoid this issue, monitor resource usage and limits regularly.

Consolidate applications within fewer VPCs if possible, using subnets and security groups to isolate resources.

Amazon VPC Quotas

Service Quotas for VPC

Requesting a Quota Increase

To resolve the issue where mobile users are being served the desktop version of the website, you need to forward the User-Agent header from CloudFront to your origin (ALB). This allows the origin to detect the type of device and serve the appropriate content.

Login to AWS Management Console:

Open the CloudFront console at Amazon CloudFront Console.

Select the Distribution:

Choose the CloudFront distribution you want to modify.

Update Cache Behavior Settings:

Go to the Behaviors tab.

Select the default behavior (or any specific behavior that you want to update) and choose Edit.

Forward Headers:

Under Cache Key and Origin Requests, choose Origin Request Policy.

Select Create Policy and include the User-Agent header in the policy.

Save the policy and apply it to the cache behavior.

This configuration ensures that the User-Agent header is forwarded to the origin, enabling it to serve different content based on the device type.

Configuring CloudFront to Forward Headers

Creating CloudFront Cache Behaviors

The most operationally efficient solution to provide email notifications and insert a record into a database when a file is put into an S3 bucket is to use S3 event notifications that target an SNS topic with two subscriptions.

Set Up S3 Event Notification:

Open the S3 console and select the bucket.

Navigate to "Properties" -> "Event notifications" -> "Create event notification."

Configure the event to trigger on s3:ObjectCreated:*.

Create an SNS Topic:

Open the SNS console and create a new topic.

Set up two subscriptions for the SNS topic:

One subscription to send the email notification.

Another subscription to invoke an AWS Lambda function that inserts the record into the database.

Lambda Function for Database Insertion:

Create an AWS Lambda function to handle the database insertion.

Configure the function to trigger from the SNS topic.

Configuring S3 Event Notifications

Amazon SNS Subscriptions

Invoking Lambda with SNS