What is everyone doing for error handling in vRA8 in case a deployment or day-2 action fails?
I can certainly generate alerts in case there is a failure in an ABX action, but if this happens do fail the action on purpose? Also how do you generate alerts in case one of the built in tasks fails instead of one of your actions?
Without notifications working in on-prem I don't think you need to spend effort on alerts if deployments fails. Generally speaking you're either launching it from the UI and can easily see the status, or launching with automation which can tail the request and alert if required. It's obviously not ideal but with how early/unfinished the product is now you may spend a lot of time iterating on something that gets thrown away with the next minor release.
As for failure states in debugging the basic build, I currently use EBS recovery runnables. Using certain properties in the payload I can either skip all EBS subscriptions, or if my custom property "debugModeEnabled" is true and the primary EBS target fails, the recovery runnable checks that property. If true don't error, if false throw the original exception; in both cases skip all remaining EBS.