In the event of a node failure within Vault's architecture, what must happen for the system to continue functioning?

In Vault's architecture, when there is a node failure, the system is designed to ensure high availability and resilience through automatic leader election. If the leader node fails, the remaining nodes within the system will automatically initiate a process to elect a new leader without the need for manual intervention. This mechanism allows the Vault to continue functioning seamlessly, maintaining its capability to handle requests and manage secrets without significant downtime or manual error.

This automatic promotion to leader is critical in environments where availability is paramount. The architecture relies on consensus algorithms that allow for quick failover, ensuring that a new leader can be established rapidly to maintain service continuity.

In contrast, the other options represent less ideal scenarios that would hinder operation. Manually restarting the failed node would lead to unnecessary delays, conducting manual leader elections would complicate operations, and resetting all nodes could result in complete downtime and loss of accessibility to secrets, highlighting why automatic leader promotion is essential for robust operational continuity.