Can a split brain situation occur in the etcd system?

In the etcd system, which is based on the Raft consensus algorithm, the split brain situation is theoretically possible, but in practice it is minimized thanks to the leader election mechanism and quorum.

Split brain is a state where the cluster is divided into two or more parts, each of which considers itself active and can accept writes, leading to data inconsistency.

In etcd:

• Writing requires a quorum (majority of nodes).
• If quorum is not achieved (for example, due to a network split), writing is blocked to prevent inconsistency.
• The leader is elected among the nodes, and only it can accept writes.

Thus, if the network splits, only one part with a quorum will continue to operate, while the other will stop accepting writes, preventing split brain.

However, with incorrect network configuration or hardware failures, temporary availability issues may occur, but etcd is designed to avoid data inconsistency.