AWS DEV: Quizzes, Cheat Sheets, Flash Cards, Mock Exams, FAQs

1

Monitor Lambda Function
You can insert logging statements into your code to help you validate that your code is working as expected. Lambda automatically integrates with Amazon CloudWatch Logs and pushes all logs from your code to a CloudWatch Logs group associated with a Lambda function (/aws/lambda/).

2

Dead Letter Queues (DLQ)
Any Lambda function invoked asynchronously is retried twice before the event is discarded. If the retries fail and you're unsure why, use Dead Letter Queues (DLQ) to direct unprocessed events to an AmazonSQS queue or an Amazon SNS topic to analyze the failure.

3

Amazon CloudWatch Agent
The Amazon CloudWatch Agent can be configured to stream logs and metrics to CloudWatch. Metric filters can be created from logs stored in CloudWatch Logs.

4

Troubleshhot unreachable instance: Secondary ENI
To allow traffic to be quickly directed to a standby instance if the application fails and becomes unreachable , a secondary ENI can be added to an instance. While primary ENIs cannot be detached from an instance, secondary ENIs can be detached and attached to a different instance.

5

Amazon ElastiCache
Amazon ElastiCache is a web service that makes it easy to deploy and run Memcached or Redis protocol-compliant server nodes in the cloud. Amazon ElastiCache improves the performance of web applications by allowing you to retrieve information from a fast, managed, in-memory caching system, instead of relying entirely on slower disk-based databases. The service simplifies and offloads the management, monitoring and operation of in-memory cache environments, enabling your engineering resources to focus on developing applications. Using Amazon ElastiCache, you can not only improve load and response times to user actions and queries, but also reduce the cost associated with scaling web applications

6

Monitor the incoming connections to the Elastic Load Balancer:
Elastic Load Balancing provides access logs that capture detailed information about requests sent to your load balancer. Each log contains information such as the time the request was received, the client's IP address, latencies, request paths, and server responses. You can use these access logs to analyze traffic patterns and troubleshoot issues.

7

Amazon Cognito Streams
Amazon Cognito Streams gives developers control and insight into their data stored in Amazon Cognito. Developers can now configure a Kinesis stream to receive events as data is updated and synchronized. Amazon Cognito can push each dataset change to a Kinesis stream you own in real time. All other options are invalid since you should use Cognito Streams

8

CloudFormation rollback
Part of your CloudFormation deployment fails due to a mis-configuration, by default what will happen? CloudFormation will rollback the entire stack

9

Troubleshoot Lambda function
If your Lambda function code is executing, but you don't see any log data being generated after several minutes, this could mean your execution role for the Lambda function did not grant permissions to write log data to CloudWatch Logs. For information about how to make sure that you have set up the execution role correctly to grant these permissions, see Manage Permissions: Using an IAM Role (Execution Role)

10

Client 429 errors
Your application is developed to pick up metrics from several servers and push them off to Cloudwatch. At times , the application gets client 429 errors. Which of the following can be done from the programming side to resolve such errors?
The main reason for such errors is that throttling is occurring when many requests are sent via API calls. The best way to mitigate this is to stagger the rate at which you make the API calls.In addition to simple retries, each AWS SDK implements exponential backoff algorithm for better flow control. The idea behind exponential backoff is to use progressively longer waits between retries for consecutive error responses. You should implement a maximum delay interval, as well as a maximum number of retries. The maximum delay interval and maximum number of retries are not necessarily fixed values and should be set based on the operation being performed, as well as other local factors, such as network latency.