Is it possible to have AWS CloudWatch Alarm send a notification to an SNS topic in another region?

Question

I am trying to create CloudWatch alarms in N. California region because that is where my EC2s are.

I want to send a notification to an SNS topic that supports both email and SMS, which n. california does not, so I created an SNS topic in Oregon instead which supports both.

The topic does not appear in the "Send Notification To:" dropdown, reading online it seems like i'm supposed to be able to click 'enter list' and put in an ARN from another region, however when I do this I get an error saying:

Error:
There was an error saving the alarm. Please try again.

Answer 1

Cross region SNS will not be available to be configured for CloudWatch alarm notifications.

Alternatively, the following steps will help you achieve the same though not a fancy way of doing.

1. Configure a SNS in the same region and configure CloudWatch to send alarm notifications to this SNS in the same region
2. Subscribe a Lambda as a consumer for this SNS to listen and process the events sent from CloudWatch
3. The Lambda will reside in the same region which will receive the event from local SNS and publish (literally forward) the message (using SNS publish method) to the SNS in a different region.
4. The SNS in other region can have SMS and/or email subscriptions.