Specify default value of ‘HA_Enabled’ instance metadata

Masakari checks if ‘HA_Enabled’ instance metadata is ‘True’ to select instances as recovery target. If ‘HA_Enabled’ is not specified, the instance is not treated as a recovery target, which is same as ‘False’ value of ‘HA_Enabled.’

This blueprint is to suggest to add a configuration to change the target selection of the instance which metadata has no HA_Enabled record. By setting the configuration to ‘True,’ Masakari adds instances without having ‘HA_Enabled’ metadata to recovery targets in system wide. The instance which ‘HA_Enabled’ metadata explicitly set to ‘False’ remains to exclude from recovery targets.

Automatic restarting the instance in failure scenario is not so harmful in most cases and typically contribute to shorten the time to recovery. Setting system wide default reduces the learning cost of users while the system provides the way to opt-out by setting the metadata per instance.