HashiCorp Vault Associate (003) Question 180
Single answer7 Vault architecture fundamentalsA company is deploying Vault for a production application used by teams in multiple regions. They want Vault to remain available if one server fails and to avoid split-brain behavior. An engineer proposes running three Vault servers with integrated storage so the nodes can elect a leader and continue operating if one node goes down. Which statement best describes how this architecture should work?
- A
With three Vault servers using integrated storage, Vault can tolerate one server failure because a quorum of two nodes can still participate in leader election and storage operations.
- B
With three Vault servers using integrated storage, all three nodes must be online at all times or Vault automatically becomes sealed to protect consistency.
- C
With three Vault servers using integrated storage, every node independently accepts writes, and Vault later merges changes between leaders after connectivity is restored.
- D
With three Vault servers using integrated storage, high availability requires an external load balancer because Vault cannot redirect client requests from standby nodes to the active node.
Show answer and explanation
Correct answer: A
Explanation
This question tests core Vault architecture fundamentals around high availability and integrated storage. Vault integrated storage uses Raft, which depends on quorum-based consensus and a single elected leader. In a three-node cluster, quorum is two, so the cluster can survive the loss of one node without split-brain. This is why HashiCorp guidance commonly recommends an odd number of nodes for Raft-based HA clusters. Standby nodes do not process writes as independent leaders; instead, they forward or redirect clients to the active node depending on request type and configuration. For exam purposes, candidates should understand the relationship between HA, Raft quorum, leader election, and why three nodes can tolerate one failure but not two. References: HashiCorp Vault documentation on Integrated Storage, Raft consensus, and High Availability behavior.
- A. Correct.
Correct. Vault integrated storage uses the Raft consensus protocol. In a three-node cluster, quorum is two nodes, so the cluster can continue functioning if one node fails. One node is active for serving write operations, and the cluster avoids split-brain by requiring quorum for leadership and committed writes.
- B. Incorrect.
Incorrect. Vault does not require all three nodes to be online in a three-node Raft cluster. The purpose of having an odd number of nodes is to maintain quorum during a failure. If two of three nodes are available, Vault can continue operating. The misconception is confusing redundancy with a requirement for full node availability.
- C. Incorrect.
Incorrect. Vault does not support multiple simultaneous leaders that later merge writes. Integrated storage relies on Raft, which elects a single leader at a time. This option describes behavior more like eventually consistent multi-master systems, which is not how Vault maintains consistency.
- D. Incorrect.
Incorrect. While an external load balancer is commonly used in front of Vault for client access, Vault standby nodes can redirect client requests to the active node in HA deployments. Therefore, a load balancer is helpful operationally but not required because Vault lacks redirect capability.