[majidazimi]

Essentially if each instance can keep track of validating transactions locally, the whole thing can be easily implemented with Bookkeeper and distributed log API [0]. Bookeeper guarantees single writer (the master node which is appending to log) for each ledger. All it needs to be done is to put concurrency control metadata (like version, timestamp, ...) inside the message so each node can validate stuff locally.

[0] https://bookkeeper.apache.org/docs/4.9.2/api/distributedlog-...