`EphemeralNode`s should certainly not be tracked. I am less sure about other `AbstractCloudSlave`s though. If they are not marked as `EphemeralNode` then they are persisted in `config.xml` and there may be a good reason for that. There may have been configuration associated with them.

On the other hand @kohsuke seems to think that even automatically provisioned cloud slaves should _not_ be ephemeral, meaning they would stick around after a Jenkins restart unless and until manually deleted or deleted by some criterion in the plugin defining the `Cloud` (such as there having been no build on it for a while). Under this interpretation, the slave is still meaningless to the user configuration despite not being `EphemeralNode`.