[Solved] You have this CloudWatch Events rule JSON:{"EventPattern": {"source": ["aws.ec2"]}, "Targets": [{"Id": "target1", "Arn":... What is the most probable reason? | AWS

AWS - CloudWatch

You have this CloudWatch Events rule JSON:

{"EventPattern": {"source": ["aws.ec2"]}, "Targets": [{"Id": "target1", "Arn": "arn:aws:lambda:us-east-1:123456789012:function:ProcessEvent"}]}

The Lambda function is not invoked when EC2 events occur. What is the most probable reason?

AThe rule is missing permissions to invoke the Lambda function.

BThe event pattern is incorrect and does not match any EC2 events.

CThe target ARN is invalid because it uses the wrong region.

DThe rule does not specify a schedule expression.

Step-by-Step Solution

Solution:

Step 1: Check event pattern
The event pattern matches EC2 events, so it is likely correct.
Step 2: Verify target ARN
The ARN appears valid and region is consistent.
Step 3: Consider permissions
EventBridge requires permission to invoke the Lambda function via resource-based policy.
Final Answer:
The rule is missing permissions to invoke the Lambda function. -> Option A
Quick Check:
Missing Lambda invoke permissions [OK]

Quick Trick: Lambda needs invoke permissions from EventBridge [OK]

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You have this CloudWatch Events rule JSON: