Using AWS Lambda to handle EventBridge events

To copy a completed snapshot to another Region

1. Create an IAM policy, such as the one shown in the following example, to provide permissions to use the CopySnapshot action and write to the EventBridge log. Assign the policy to the user that will handle the EventBridge event.

   {
     "Version": "2012-10-17",
     "Statement": [
       {
         "Effect": "Allow",
         "Action": [
           "logs:CreateLogGroup",
           "logs:CreateLogStream",
           "logs:PutLogEvents"
         ],
         "Resource": "arn:aws:logs:*:*:*"
       },
       {
         "Effect": "Allow",
         "Action": [
           "ec2:CopySnapshot"
         ],
         "Resource": "*"
       }
     ]
   }

2. Define a function in Lambda that will be available from the EventBridge console. The sample Lambda function below, written in Node.js, is invoked by EventBridge when a matching createSnapshot event is emitted by Amazon EBS (signifying that a snapshot was completed). When invoked, the function copies the snapshot from us-east-2 to us-east-1.

   // Sample Lambda function to copy an EBS snapshot to a different Region
    
   var AWS = require('aws-sdk');
   var ec2 = new AWS.EC2();
    
   // define variables
   var destinationRegion = 'us-east-1';
   var sourceRegion = 'us-east-2';
   console.log ('Loading function');
    
   //main function
   exports.handler = (event, context, callback) => {
    
       // Get the EBS snapshot ID from the event details
       var snapshotArn = event.detail.snapshot_id.split('/');
       const snapshotId = snapshotArn[1];
       const description = `Snapshot copy from ${snapshotId} in ${sourceRegion}.`;
       console.log ("snapshotId:", snapshotId);
   
       // Load EC2 class and update the configuration to use destination Region to initiate the snapshot.
       AWS.config.update({region: destinationRegion});
       var ec2 = new AWS.EC2();
   
       // Prepare variables for ec2.modifySnapshotAttribute call
       const copySnapshotParams = {
           Description: description,
           DestinationRegion: destinationRegion,
           SourceRegion: sourceRegion,
           SourceSnapshotId: snapshotId
       };
    
       // Execute the copy snapshot and log any errors
       ec2.copySnapshot(copySnapshotParams, (err, data) => {
           if (err) {
               const errorMessage = `Error copying snapshot ${snapshotId} to Region ${destinationRegion}.`;
               console.log(errorMessage);
               console.log(err);
               callback(errorMessage);
           } else {
               const successMessage = `Successfully started copy of snapshot ${snapshotId} to Region ${destinationRegion}.`;
               console.log(successMessage);
               console.log(data);
               callback(null, successMessage);
           }
       });
   };                

   To ensure that your Lambda function is available from the EventBridge console, create it in the Region where the EventBridge event will occur. For more information, see the AWS Lambda Developer Guide.

3. Open the Amazon EventBridge console at https://console.aws.amazon.com/events/.

4. In the navigation pane, choose Rules, and then choose Create rule.

5. For Step 1: Define rule detail, do the following:

   1. Enter values for Name and Description.

   2. For Event bus, keep default.

   3. Ensure that Enable the rule on the selected event bus is toggled on.

   4. For Event type, select Rule with an event pattern.

   5. Choose Next.

6. For Step 2: Build event pattern, do the following:

   1. For Event source, select AWS events or EventBridge partner events.

   2. In the Event pattern section, for Event source, ensure that AWS service is selected, and for AWS service, select EC2.

   3. For Event type, select EBS Snapshot Notification, select Specific event(s), and then choose createSnapshot.

   4. Select Specific result(s) and then choose succeeded.

   5. Choose Next.

7. For Step 3: Select targets, do the following:

   1. For Target types, choose AWS service.

   2. For Select target, choose Lambda function, and for Function select the function that you created earlier.

   3. Choose Next

8. For Step 4: Configure tags, specify tags for the rule if needed, and then choose Next.

9. For Step 5: Review and create, review the rule and then choose Create rule.