Concepts
Notifications and alarms are pivotal components of monitoring in AWS. Notifications are messages sent to notify users of changes or updates in their AWS environment, while alarms are automated responses triggered by specific thresholds being met or exceeded in AWS services.
- Amazon CloudWatch Alarms: These alarms monitor a single metric over a specified period and perform one or more actions based on the value of the metric relative to a given threshold.
- Amazon SNS (Simple Notification Service): A web service that coordinates and manages the delivery or sending of messages to subscribing endpoints or clients.
- AWS CloudTrail: Enables governance, compliance, operational auditing, and risk auditing of your AWS account by logging and monitoring account activity.
Troubleshooting with CloudWatch Alarms
Scenario: You have an EC2 instance with a CloudWatch alarm set to trigger if the CPU utilization goes above 80% for 5 minutes.
- Investigate the Alarm:
- Check the Alarm Details.
- View the alarm history to understand when and why it was triggered.
- Verify Instance Metrics:
- Go to CloudWatch > Metrics.
- Filter by EC2 > Per-Instance Metrics.
- Review the CPU Utilization metric.
- Analyze Logs (if you have CloudWatch Logs set up for your instance):
- Review the application and system logs to check for errors or unusual activity around the time when the CPU utilization spiked.
- Check for Changes:
- Utilize AWS Config or consult the recent changes using AWS CloudTrail to see if there were recent changes to the instance or related services.
Corrective Actions
Upon identifying the issue, you can take one of the following corrective actions:
- Modify Instance:
- Scale up the instance type to a larger size with more CPU power.
- Scale out by adding more instances behind a load balancer if it’s an application that can be horizontally scaled.
- Optimize Code:
- If the CPU utilization spike is due to inefficient code, work on optimizing the code.
- Implement Scaling Policies:
- Set up Auto Scaling policies to automatically handle load changes.
- Alter Alarm Threshold:
- If the threshold set was too low and it’s normal for the instance to have a higher CPU utilization, consider revising the threshold value of the alarm.
Automating Response using Amazon SNS
Upon an alarm activation, you may wish to automate corrective actions through Amazon SNS.
- Configure an SNS Topic and Subscription:
- In the SNS dashboard, create a new topic.
- Subscribe to the topic using an endpoint (e.g., email, SMS, or Lambda function).
- Link to CloudWatch Alarm:
- Modify the CloudWatch alarm to perform an SNS action when triggered.
- Select the SNS topic you created as the target for this action.
- Automate Corrective Actions with Lambda (Optional):
- Create an AWS Lambda function to take a specific action (like adjusting Auto Scaling).
- Subscribe the Lambda function to the SNS topic.
Example of an SNS Topic Subscription using AWS CLI
aws sns subscribe \
–topic-arn “arn:aws:sns:REGION:ACCOUNT_ID:TOPIC_NAME” \
–protocol EMAIL \
–notification-endpoint user@example.com
Conclusion
Effective monitoring and responsive troubleshooting are essential for maintaining the health and performance of your AWS environment. By utilizing tools such as CloudWatch, SNS, and Lambda, SysOps Administrators can automate responses to events and ensure reliability and efficiency. Understanding these processes is beneficial for those pursuing the AWS Certified SysOps Administrator – Associate certification and for professionals managing AWS production environments.
Answer the Questions in Comment Section
True or False: Amazon CloudWatch can be used to monitor AWS environments and send notifications for predefined thresholds.
- (A) True
- (B) False
Answer: A
Explanation: Amazon CloudWatch provides monitoring for AWS cloud resources and applications, allowing users to set alarms for when particular thresholds are breached.
When an Amazon EC2 instance becomes unreachable, which of the following steps should you take first?
- (A) Terminate the instance immediately.
- (B) Review the instance status checks.
- (C) Reboot another instance.
- (D) Increase the instance size.
Answer: B
Explanation: The first step should always be to review the instance status checks to identify if there is an issue with the instance itself or the underlying infrastructure.
You receive a notification that your EC2 instance has high CPU utilization. What should be the first step to resolve this?
- (A) Upgrade the instance to a larger size.
- (B) Analyze the workload on the instance.
- (C) Set up more CloudWatch alarms.
- (D) Do nothing until the issue persists.
Answer: B
Explanation: Analyzing the workload is the first step in understanding the cause of high CPU utilization before deciding on actions such as resizing the instance.
Multiple Select: What actions can be triggered by an Amazon CloudWatch Alarm? (Select TWO)
- (A) Send an SMS message.
- (B) Automatically update the instance type.
- (C) Terminate an EC2 instance.
- (D) Publish a message to an SNS topic.
- (E) Delete unused Elastic Load Balancers.
Answer: A, D
Explanation: CloudWatch Alarms can perform various actions, such as sending notifications through SMS messages and publishing messages to SNS topics. Other actions like terminating instances or updating instance types require additional automation through AWS Lambda or Auto Scaling policies.
True or False: Amazon SNS cannot send notifications to an AWS Lambda function.
- (A) True
- (B) False
Answer: B
Explanation: Amazon Simple Notification Service (SNS) can indeed send notifications to AWS Lambda for automated response to alarms or notifications.
Which AWS service can automatically perform corrective actions based on CloudWatch alarm triggers?
- (A) AWS Auto Scaling
- (B) AWS Config
- (C) AWS Lambda
- (D) All of the above
Answer: D
Explanation: All the listed services can be used to perform actions in response to CloudWatch alarm triggers. Auto Scaling can adjust capacity, AWS Config can track and act upon configuration changes, and AWS Lambda can execute custom functions.
True or False: CloudWatch Logs can trigger a CloudWatch Alarm.
- (A) True
- (B) False
Answer: A
Explanation: CloudWatch Logs can be monitored for specific patterns or keyword occurrences, which can then trigger a CloudWatch Alarm.
Single Select: Which EC2 status check failure would typically require AWS intervention rather than customer intervention?
- (A) Instance status check
- (B) System status check
Answer: B
Explanation: System status checks failure indicates a problem with the underlying infrastructure that usually requires intervention by AWS.
True or False: AWS CloudTrail is used to monitor API calls in the AWS platform and can be configured to send alerts when specific API calls are made.
- (A) True
- (B) False
Answer: A
Explanation: AWS CloudTrail records AWS API calls and can integrate with Amazon CloudWatch Logs to enable monitoring and alerting on specific API activity.
Multiple Select: Which factors might trigger a scaling activity in an Auto Scaling group? (Select TWO)
- (A) A scheduled action.
- (B) High CPU utilization.
- (C) An AWS user logging into the AWS Management Console.
- (D) A decrease in Elastic Load Balancer capacity.
- (E) An Amazon S3 bucket reaching its storage limit.
Answer: A, B
Explanation: Auto Scaling policies can be triggered by a variety of factors, including a scheduled action and high CPU utilization.
Great blog post! I learned a lot about troubleshooting with CloudWatch alarms.
Can someone explain the best approach to handle high CPU usage notifications?
Thank you for this informative article!
I think the post could use more real-world examples.
What are the common alarms one should set up for an RDS instance?
This blog post is a lifesaver. I was struggling with setting up alarms efficiently.
How do you handle ‘Instance Termination’ alarms?
Appreciate the detailed explanations!