AWS Certified Developer: Monitoring and Troubleshooting
A Software Engineer is refactoring a Lambda function, which currently uses a public GraphQL API from the Internet as part of its processing. The new requirement states that the function should process the data and store the results to a database hosted in your VPC. The additional VPC-specific information has already been configured in the function and the database connection has been successfully established. However, after testing, he found that the function can't connect to the Internet anymore. What 2 tasks should the Software Engineer do to fix this issue?
* Ensure that the associated security group of the Lambda function allows outbound connections * Add a NAT gateway to your VPC
An API gateway with a Lambda proxy integration takes a long time to complete its processing. There were also occurrences where some requests timed out. You want to monitor the responsiveness of your API calls as well as the underlying Lambda function. What two CloudWatch metrics should you use to troubleshoot this issue?
* Integration Latency: measure responsiveness of backend * Latency: measure responsiveness of API call as a whole
A Lambda-based application consists of several functions. Once triggered, these functions will call various downstream resources such as a DynamoDB table or an S3 bucket, or make other API calls. There is a requirement to allow the developers to trace the event source that invoked your Lambda functions and trace the downstream calls that your functions made. The number of requests and the execution duration per request should also be monitored. What two services should you use to achieve this?
* X-Ray: to trace the event source and downstream calls * CloudWatch: to monitor the number of requests and the execution duration per request
A recently deployed Lambda function has an intermittent issue in processing customer data. You enabled the active tracing option in order to detect, analyze, and optimize performance issues of your function using the X-Ray service. What two environment variables are used by AWS Lambda to facilitate communication with X-Ray?
* _X_AMZN_TRACE_ID * AWS_XRAY_CONTEXT_MISSING
A serverless application, which is composed of Lambda functions integrated with API Gateway and DynamoDB, processes ad hoc requests that are sent by its users. Due to the recent spike in incoming traffic, some of your customers are complaining that they are getting HTTP 504 errors from time to time. What is the MOST likely cause of this issue?
API Gateway request has timed out because the underlying Lambda function has been running for more than 29 seconds.
An application, which already uses X-Ray, generates thousands of trace data every hour. The developer wants to use a filter expression that will limit the results based on custom attributes or keys that he specifies. How should the developer refactor the application in order to filter the results in the X-Ray console?
Add custom attributes as annotations in your segment document
An online stock trading platform is hosted in an Auto Scaling group of EC2 instances with an Application Load Balancer in front to evenly distribute the incoming traffic. The developer must capture information about the IP traffic going to and from network interfaces in your VPC to comply with financial regulatory requirements. What should the developer do to meet the requirement?
Create a flow log in your VPC.
A new IT policy requires you to trace all calls that your Node.js application sends to external HTTP web APIs as well as SQL database queries. You have to instrument your application, which is hosted in Elastic Beanstalk, in order to properly trace the calls via the X-Ray console. What should you do to comply with the given requirement?
Enable the X-Ray daemon by including the xray-daemon.config file in the .ebextensions directory of your source code.
A mission-critical application is required to have a monitoring system which can provide immediate insight into its sub-minute activity. You are required to collect the data of all of the users who are currently logged in to the system every 10 seconds. What is the MOST suitable solution that you should do to meet the above requirements?
Publish a high-resolution custom metric to CloudWatch
A developer configured an Amazon API Gateway proxy integration named MyAPI to work with a Lambda function. However, when the API is being called, the developer receives a 502 Bad Gateway error. She tried invoking the underlying function but it properly returns the result in XML format. What is the MOST likely root cause of this issue?
There is an incompatible output type returned from a Lambda proxy integration backend.
