VA-003 Explain Vault architecture Practice Question
A company runs Vault in a single cluster with three nodes using the Raft storage backend. The nodes are behind a load balancer that distributes traffic to all nodes. The operations team notices that occasionally, write operations (e.g., writing a secret or creating a policy) fail with a '502 Bad Gateway' error, while read operations succeed. The Vault audit logs show no errors. The load balancer health checks are configured to check the /v1/sys/health endpoint with a 200 response expected. The Vault nodes are all unsealed and the cluster is healthy. Which of the following is the most likely cause of the intermittent write failures?
⚠ Common exam trap
HashiCorp often tests the misconception that all Vault nodes in a cluster can handle writes equally, but in reality only the leader node processes write operations; the trap here is assuming that a healthy, unsealed node can always accept writes.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The load balancer is sending write requests to standby nodes, which cannot handle writes.
In a Vault cluster with Raft storage, only the elected leader node can handle write operations (e.g., writing secrets, creating policies). Standby nodes serve read requests and forward writes to the leader. If the load balancer distributes traffic to all nodes without considering leadership, write requests sent to a standby node will fail with a 502 Bad Gateway error because the standby cannot process the write locally and the load balancer may not properly handle the forwarded response or timeout.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The Raft storage backend does not support write operations.
Why it's wrong here
Raft supports writes, but only on the leader.
- ✓
The load balancer is sending write requests to standby nodes, which cannot handle writes.
Why this is correct
Only the active node can process writes; standby nodes return a 502.
- ✗
The load balancer is not configured to use the /v1/sys/leader endpoint for routing.
Why it's wrong here
Even if the load balancer used the leader endpoint, the issue is that standby nodes reject writes, not that routing is incorrect.
- ✗
One of the Vault nodes is sealed, causing write requests to fail.
Why it's wrong here
The problem states all nodes are unsealed.
Go deeper
Related to this question
About these practice questions
Courseiva writes every VA-003 question from scratch — 498 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or dumps. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This VA-003 practice question is part of Courseiva's free HashiCorp certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the VA-003 exam.