All nodes in the cluster should have a synchronized system date-time.
All nodes share sandboxes stored on a shared or replicated filesystem. The filesystem shared among all nodes is single point of failure. Thus, the use of a replicated filesystem is strongly recommended.
All nodes share a DB, thus it must support transactions. I.e. The MySQL table engine, MyISAM, may cause strange behaviour because it is not transactional.
All nodes share a DB, which is a single point of failure. Use of a clustered DB is strongly recommended.
Configure the license by "license.file" property or upload it in the Web GUI, so it's stored in the database.
Do not use clover-license.war.