CloudWatch Alarms

# CloudWatch Alarms > Set up CloudWatch monitoring and alarms You are an AWS CloudWatch expert. The user wants to set up CloudWatch monitoring and alarms to track metrics, detect anomalies, and trigger notifications. ## What to check first - Verify AWS CLI is installed and configured: `aws sts get-caller-identity` - Confirm IAM permissions include `cloudwatch:PutMetricAlarm`, `cloudwatch:PutMetricData`, and `sns:Publish` - Check if SNS topic exists for notifications: `aws sns list-topics` ## Steps 1. Create an SNS topic for alarm notifications using `aws sns create-topic --name cloudwatch-alarms` 2. Subscribe your email to the SNS topic: `aws sns subscribe --topic-arn arn:aws:sns:region:account:cloudwatch-alarms --protocol email --notification-endpoint [email protected]` 3. Confirm the SNS subscription by clicking the email link AWS sends 4. Identify the metric namespace and dimensions for your resource (e.g., `AWS/EC2` for EC2 instances) 5. Create a threshold alarm using `PutMetricAlarm` that triggers when a metric exceeds a statistic over a specified period 6. Set the `ComparisonOperator` (GreaterThanThreshold, LessThanThreshold, etc.) and `EvaluationPeriods` (consecutive periods before alarm triggers) 7. Bind the alarm to your SNS topic in the `AlarmActions` parameter so notifications are sent when the alarm state changes 8. Test the alarm by publishing a test metric: `aws cloudwatch put-metric-data --metric-name TestMetric --value 100` ## Code ```python import boto3 from datetime import datetime cloudwatch = boto3.client('cloudwatch') sns = boto3.client('sns') # Step 1: Create SNS topic (if not exists) topic_response = sns.create_topic(Name='cloudwatch-alarms') topic_arn = topic_response['TopicArn'] print(f"SNS Topic ARN: {topic_arn}") # Step 2: Create a high CPU alarm for EC2 instance cloudwatch.put_metric_alarm( AlarmName='High-CPU-Usage-Production', ComparisonOperator='GreaterThanThreshold', EvaluationPeriods=2, MetricName='CPUUtilization', Namespace='AWS/EC2', Period=300, # 5 minutes Statistic='Average', Threshold=80.0, ActionsEnabled=True, AlarmActions=[topic_arn], AlarmDescription='Alert when EC2 CPU exceeds 80% for 10 minutes', Dimensions=[ { 'Name': 'InstanceId', 'Value': 'i-0123456789abcdef0' # Replace with your instance ID } ] ) print("CPU ``` *Note: this example was truncated in the source. See [the GitHub repo](https://github.com/Samarth0211/claude-skills-hub) for the latest full version.* ## Common Pitfalls - Treating this skill as a one-shot solution — most workflows need iteration and verification - Skipping the verification steps — you don't know it worked until you measure - Applying this skill without understanding the underlying problem — read the related docs first ## When NOT to Use This Skill - When a simpler manual approach would take less than 10 minutes - On critical production systems without testing in staging first - When you don't have permission or authorization to make these changes ## How to Verify It Worked - Run the verification steps documented above - Compare the output against your expected baseline - Check logs for any warnings or errors — silent failures are the worst kind ## Production Considerations - Test in staging before deploying to production - Have a rollback plan — every change should be reversible - Monitor the affected systems for at least 24 hours after the change --- *From [CLSkills.in](https://clskills.in/browse) — 2,300+ free Claude Code skills*