Start EC2 instances event base.

Question

I would like to start an ec2 instance event base. Suppose instance is stopped and when someone trying to SSH/RDP or by running a python script, instance should start may be through lambda function or using event bridge.

Answer

What about triggering the connection in the Systems Manager session manager to start Lambda?  
This would allow us to run Lambda and launch EC2 when Amazon EventBridge detects a session manager event.  
Below is an example of an Amazon EventBridge event pattern.

```
{
  "source": ["aws.ssm"],
  "detail-type": ["AWS API Call via CloudTrail"],
  "detail": {
    "eventSource": ["ssm.amazonaws.com"],
    "eventName": ["StartSession"],
    "requestParameters": {
      "target": ["EC2 ID"]
    }
  }
}
```

Another possibility would be to enable VPC flow logging and use CloudWatch Logs subscription filters to share logs to Lambda when there is an SSH connection.  
https://docs.aws.amazon.com/AmazonCloudWatch/latest/logs/SubscriptionFilters.html#LambdaFunctionExample

Please refer to the example in the following document for the Lambda function to be used for startup.  
https://repost.aws/knowledge-center/start-stop-lambda-eventbridge

Start EC2 instances event base.

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