How does Auto Healing or Self Healing work?

Every instance has an agent process called scalarium-agent running. This agent keeps a permanent connection to the Scalarium backend.

If this agent disconnects or times out, Scalarium notices and starts to observe the instance. If the instance agent does not reconnect within a couple of minutes, Scalarium 'auto-heals' the instance.

Auto Healing an instance means to first stop the instance to make sure it is really shut down. After the shutdown, Scalarium will restart the instance as defined in Scalarium. So a new AWS instance will be started with the same configuration as the instance defined in Scalarium. It will have the same instance name, the same EBS volumes mounted, and the same roles and configuration applied.

Auto Healing is enabled for all instances but MySQL servers by default. You can disable auto healing if you want to handle this cases by yourself or enable it if you don't.