cluster with cloud and physical dedicated servers

  1. Is it possible to form a cluster between physical dedicated server and cloud server?
  2. cluster between multiple servers vs cluster in a single box - which one is good? and also tell me the differences between them?
  1. Yes it’s possible, only depends on what cloud server do you mean.
  2. If you want high availability then only multiple servers make sense. Not sure what differences you wanted to be explained?