20 Must-Know AWS CloudWatch Interview Questions with Answers
I have prepared the top 20 AWS CloudWatch interview questions and answers:
- What is AWS CloudWatch?
AWS CloudWatch is a monitoring service for AWS resources and applications, providing insights into performance, operational health, and resource utilization. It allows you to collect and track metrics, set alarms, and create automated actions based on defined conditions.
- What are the key features of AWS CloudWatch?
The key features of AWS CloudWatch include:
- Metrics: Collect and track performance data
- Alarms: Set custom thresholds for metrics
- Dashboards: Visualize metrics and alarms
- Logs: Centralize log data from various AWS services
- Events: Respond to changes in resource states
- Anomaly Detection: Identify unusual metric behavior
- What is the difference between CloudWatch and CloudTrail?
CloudWatch is primarily focused on performance monitoring, providing metrics, alarms, and logs for AWS resources. CloudTrail, on the other hand, is an auditing service that records AWS API calls, helping with security analysis, compliance, and operational troubleshooting.
- What are the default metrics available in CloudWatch for an EC2 instance?
The default metrics for an EC2 instance include:
- CPU Utilization
- Disk Read/Write Operations
- Disk Read/Write Bytes
- Network Packets In/Out
- Network Bytes In/Out
- Status Check Failed (Any, Instance, System)
- What is the difference between a basic and detailed monitoring in CloudWatch?
Basic monitoring collects metrics data every 5 minutes, while detailed monitoring collects data every 1 minute. Detailed monitoring incurs additional charges.
- How can you monitor custom application metrics using CloudWatch?
You can use the CloudWatch Agent or custom scripts with the AWS SDK to publish custom metrics to CloudWatch.
- What is an Alarm in CloudWatch, and what actions can be taken when an alarm is triggered?
An Alarm is a user-defined condition based on a metric. When an alarm is triggered, it can perform actions such as sending a notification via SNS, stopping or terminating an EC2 instance, or scaling an Auto Scaling group.
- What is CloudWatch Logs, and what are its primary use cases?
CloudWatch Logs is a log management service that centralizes logs from various AWS services, enabling you to monitor, store, and access log files. Primary use cases include troubleshooting, security analysis, and application performance monitoring.
- How can you use CloudWatch Events for operational tasks?
CloudWatch Events allows you to trigger Lambda functions, send notifications, or change resource states based on events. You can use it for operational tasks such as starting and stopping instances, creating backups, or deploying code.
- What is the retention period for CloudWatch Logs?
By default, CloudWatch Logs retains log data for 30 days, but you can configure a retention period from 1 day to indefinite.
- Can you monitor on-premises servers with CloudWatch?
Yes, you can use the CloudWatch Agent to collect metrics and logs from on-premises servers and publish them to CloudWatch.
- What is the cost associated with AWS CloudWatch?
CloudWatch charges are based on metrics, alarms, dashboards, log data ingestion, storage, and data transfer.
- What is the maximum retention period for CloudWatch Metrics?
CloudWatch Metrics are retained for 15 months.
- How can you monitor Lambda functions with CloudWatch?
Lambda automatically integrates with CloudWatch, providing metrics such as Invocation Count, Duration, Errors, and Throttles. Additionally, Lambda logs can be stored in CloudWatch Logs.
- What is the difference between a Period and a Granularity in CloudWatch?
A Period refers to the length of time over which a metric is aggregated, while Granularity refers to the time interval between data points in a metric. For example, if you’re monitoring CPU utilization with a period of 5 minutes, the metric data will be aggregated every 5 minutes. Granularity determines the frequency of metric data collection, such as 1-minute intervals for detailed monitoring or 5-minute intervals for basic monitoring.
- What is CloudWatch Anomaly Detection?
CloudWatch Anomaly Detection is a feature that applies machine learning algorithms to continuously analyze historical metric data, creating a model that represents expected behavior. It helps identify unusual metric patterns, enabling you to set more accurate alarms and reduce false positives.
- How can you monitor Amazon RDS instances with CloudWatch?
Amazon RDS automatically sends metrics to CloudWatch, such as CPU Utilization, Free Storage Space, and Database Connections. You can create alarms based on these metrics and visualize them on a dashboard.
- What is the difference between CloudWatch Metrics and CloudWatch Logs?
CloudWatch Metrics are numerical data points representing the performance and operational health of AWS resources, while CloudWatch Logs are text-based records of events generated by applications and services.
- How do you secure CloudWatch Logs?
CloudWatch Logs data is encrypted at rest using AWS Key Management Service (KMS) keys. You can use IAM policies to control access, and CloudWatch Logs integrates with AWS CloudTrail to provide an audit trail of API calls.
- Can you export CloudWatch data to external services?
Yes, you can export CloudWatch data to external services. For example, you can export CloudWatch Metrics to Amazon S3 for long-term storage or analysis, or you can stream CloudWatch Logs to Elasticsearch, Splunk, or custom destinations using Amazon Kinesis Data Firehose.