Proxmox VE: nodes, clusters, quorum and high availability
How Proxmox VE nodes form a cluster with Corosync and the cluster file system, what quorum protects and what happens without it, when a QDevice helps, how to remove a node safely, and what the HA manager needs (three nodes, shared storage, watchdog fencing) to restart guests after a failure.
- Level
- Intermediate
- Length
- About 55 minutes
- Contents
- 3 lessons · final exam
- Status
- Published · updated 1 Oct 2026
- Proxmox VE · open source
Skills you'll practise
- Describe the network and time requirements for a Proxmox VE cluster and why Corosync needs a low-latency, preferably dedicated network
- Explain what quorum loss does to a node and when an external vote (QDevice) is appropriate
- Remove a node from a cluster without risking the cluster's consistency
- List the requirements for HA and explain how self-fencing with a watchdog protects data
- Choose the right HA resource state and use maintenance mode for planned node work
Course outline
- 1.Nodes and the cluster file systemLesson · 17 min
- 2.Quorum, two-node clusters and removing nodesLesson · 18 min
- 3.High availabilityLesson · 20 min
- 4.Proxmox VE: nodes, clusters, quorum and high availability: knowledge checkKnowledge check · 13 questions
- 5.Two-node cluster: one node down, nothing will startScenario
- 6.Final exam8 questions · passing it completes the course, so people who already know the material can test out
Sources it draws on
The lessons and questions are written from these references, so learners can go back to the original.
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