AWS metrics and logging services (for example, CloudWatch, X-Ray)

What is Amazon CloudWatch and how does it support monitoring in AWS?

Amazon CloudWatch is a monitoring service for AWS cloud resources and the applications running on AWS. It provides data and actionable insights to monitor applications, respond to system-wide performance changes, optimize resource utilization, and get a unified view of operational health. CloudWatch collects monitoring and operational data in the form of logs, metrics, and events, providing a unified view of AWS resources, applications, and services that run on AWS and on-premises servers.

How can you monitor and log API calls made to your AWS resources?

You can monitor and log API calls made to your AWS resources using AWS CloudTrail. CloudTrail logs all API requests and responses, including the identity of the API caller, the time of the call, the source IP address, request parameters, and response elements. This helps in security analysis, resource change tracking, and compliance auditing.

What is AWS X-Ray and what problem does it solve for developers and DevOps engineers?

AWS X-Ray is a service that provides insights into how your application and its underlying services are performing to help developers and DevOps engineers analyze and debug production, distributed applications, such as those built using a microservices architecture. X-Ray provides an end-to-end view of requests as they travel through your application, showing a map of your application’s underlying components.

Can you explain the difference between metrics and logs in the context of AWS monitoring services?

Metrics in AWS are numerical values that represent different aspects of a system at a particular point in time; they are aggregated over periods of time. For example, CPU usage, network bandwidth, and disk I/O are metrics available in CloudWatch. Logs, on the other hand, are records of events that happen within your application or resource. They provide more granular information about the operational health of systems and are often used for debugging and troubleshooting purposes.

How does Amazon CloudWatch Alarms work and when would you use them?

Amazon CloudWatch Alarms allows you to watch a single CloudWatch metric or the result of a math expression based on CloudWatch metrics. You can set alarms to notify you when a metric reaches a certain threshold over a predefined period of time. They can be used to trigger automatic actions or to initiate notifications, enabling you to react promptly to any operational issues.

What is the retention period for CloudWatch Logs and how can it be customized?

By default, CloudWatch Logs are kept indefinitely unless a retention policy is set, allowing you to transition or archive your log data automatically without any action on your part. AWS provides several predefined retention periods, ranging from 1 day up to 10 years, which you can apply to your log groups to control the retention duration for your logs.

Can you describe how you would create a dashboard in CloudWatch and what information it might display?

To create a dashboard in CloudWatch, you would navigate to the CloudWatch console, click on Dashboards, and then create a new dashboard by specifying a name and adding widgets. Widgets can display different types of information such as metrics, graphs, and alarms. You can customize the metrics shown on each widget to include data such as CPU utilization, response times, or error rates of your applications and services.

Explain the concept of high-resolution metrics in CloudWatch and when you would need them?

High-resolution metrics in CloudWatch are metrics that allow data to be available in frequencies of less than 1 minute, down to 1-second granularity. They are beneficial when you want more granular data to monitor your applications and resources, making it possible to react more quickly to events and incidents.

In CloudWatch, what is the difference between metrics and events, and when would you use each one?

Metrics in CloudWatch are quantitative data, such as performance statistics and counters that are measured over intervals of time. Events, however, are records indicating a change in your AWS environment, often in response to resources created, modified, or deleted. Metrics are used for real-time monitoring of operational health and performance, while events are used for alerting and triggering automated workflows or responses to environmental changes.

How do you secure access to the log data in CloudWatch Logs?

Access to CloudWatch Logs is secured by AWS Identity and Access Management (IAM) policies that define who has permission to view, create, or modify logs. You can attach these policies to IAM users, groups, or roles. Furthermore, you can use resource-based policies to control access on individual log groups and use encryption options to secure log data at rest and in transit.

Explain how AWS X-Ray’s trace analysis helps in identifying performance bottlenecks?

AWS X-Ray’s trace analysis allows you to follow the path of a request through your application, providing a visual representation of the components involved, and the amount of time each component took to respond. This makes it easier to identify performance bottlenecks as you can pinpoint which service or application component is adding significant latency and requires optimization.

What is the difference between standard and detailed monitoring in Amazon EC2, and how does it relate to CloudWatch?

Amazon EC2 provides two levels of monitoring. Standard monitoring occurs at five-minute intervals and is provided for free. Detailed monitoring reports data at one-minute intervals but incurs additional charges. Detailed monitoring provides more granular data, thus allowing for more immediate and precise diagnostics. Both types of monitoring metrics are available to view in CloudWatch.