139 lines
4.8 KiB
Markdown
139 lines
4.8 KiB
Markdown
# PVE 3-Node HA Cluster for Iron Legion
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**Status:** Draft | **Author:** Artemis | **Date:** 2026-06-04
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## 1. Objective
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Configure MK33, MK34, and MK39 as a Proxmox VE 3-node cluster with shared NFS storage from TrueNAS. Enable manual live migration of VMs/LXCs between nodes, and optionally automatic HA failover for critical workloads.
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## 2. Current State
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| Node | CPU | RAM | Storage | Role |
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|------|-----|-----|---------|------|
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| MK33 (Silver Centurion) | Intel N150 4c/4t | 16GB | Local SSD | PVE HA |
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| MK34 (Southpaw) | Intel N150 4c/4t | 16GB | Local SSD | PVE HA |
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| MK39 (Gemini) | Intel N150 4c/4t | 16GB | Local SSD | PVE HA (spare)
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| TrueNAS SCALE | 4c | 11GB | HDD pool | NFS server |
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All nodes on `192.168.0.0/18`. TrueNAS at `192.168.16.254`.
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## 3. Architecture
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### 3.1 Cluster Model: Proxmox 3-Node Cluster (No Ceph)
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```
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MK33 (192.168.7.33) ──┐
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├─ Corosync Ring ── Shared NFS (TrueNAS)
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MK34 (192.168.7.34) ──┤
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│
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MK39 (192.168.7.39) ──┘
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```
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- **Quorum:** 3-node cluster = 2 votes needed for quorum. If one node dies, remaining 2 form quorum.
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- **Shared storage:** TrueNAS NFSv4.2 export `/mnt/Ice/Backup`
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- **HA manager:** Proxmox HA services (`pve-ha-crm`, `pve-ha-lrm`) for automatic restart
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### 3.2 Storage Flow
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```
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Build on local disk → Test workload → Shutdown → Move disk to NFS → Restart on NFS
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↓
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If node fails: HA manager detects → Restarts VM/LXC on surviving node (same NFS disk)
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```
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### 3.3 Workload Planning
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| Type | Count per node | Resources each |
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|------|---------------|----------------|
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| VM (general) | 1 | 4 vCPU, 4096 MB RAM |
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| LXC (lightweight) | 5–10 | 1 vCPU, 512–1024 MB RAM |
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**Total per node estimated:** 9–14 vCPUs (but N100 is 4c/4t — LXCs share cores opportunistically via cgroups)
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**Total RAM per node:** VM 4GB + 5×1GB LXCs = ~9GB allocated, 7GB headroom
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## 4. Pros vs Cons
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### 4.1 3-Node Cluster (Recommended)
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**Pros:**
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- Unified web UI for all 3 nodes from any one node
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- Live migration of VMs/LXCs between nodes (zero downtime)
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- Automatic HA failover for critical VMs/LXCs
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- Quorum maintained with 2 of 3 nodes online
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- Shared NFS storage means VMs are portable across nodes
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**Cons:**
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- Corosync ring traffic adds minor network overhead
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- If 2 nodes fail simultaneously, quorum lost, cluster stops
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- HA failover is restart (brief downtime), not live migration
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- N100 CPU is modest — 3 VMs + 15 LXCs across cluster is tight but workable
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### 4.2 Standalone Nodes (Current)
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**Pros:**
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- Simple, no cluster complexity
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- Node failure doesn't affect others
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- No Corosync network overhead
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**Cons:**
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- No live migration — moving a VM requires export/import
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- No automatic failover — manual intervention if node dies
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- 3 separate web UIs to manage
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## 5. Implementation Plan
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### Phase 1: Cluster Formation
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1. Add all 3 nodes to `/etc/hosts` on each node (or DNS via Technitium)
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2. On MK33: `pvecm create iron-legion`
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3. On MK34/MK39: `pvecm add 192.168.7.33`
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4. Verify: `pvecm status` shows 3 nodes, quorum 2/3
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### Phase 2: NFS Storage Setup
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1. Ensure TrueNAS exports `/mnt/Ice/Backup` with:
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- NFSv4.2
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- `maproot` or `mapall` to `root` (PVE nodes need root access)
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- ACL allows `192.168.0.0/18`
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2. On PVE Datacenter → Storage → Add → NFS:
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- ID: `truenas-backup`
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- Server: `192.168.16.254`
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- Export: `/mnt/Ice/Backup`
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- Content: `images,rootdir`
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3. Verify storage shows on all 3 nodes
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### Phase 3: HA Configuration
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1. Proxmox HA → Add groups:
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- `critical`: nodes mk33,mk34,mk39 (any node)
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- `local-only`: single-node constraint for local-disk VMs
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2. For each VM/LXC on NFS storage:
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- Datacenter → HA → Add → Select VM → Group `critical` → Start on any
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3. Start fencing daemon if IPMI/ watchdog available (optional for N100)
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### Phase 4: Workload Migration Testing
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1. Build a test LXC on local storage
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2. Migrate disk to NFS: `Move disk` → target `truenas-backup`
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3. Verify LXC starts from NFS
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4. Test live migration: right-click → Migrate → select target node
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5. Test HA failover: power off source node, verify restart on surviving node
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## 6. Open Questions
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1. Do we need HA fencing? (IPMI not available on N100 — watchdog only)
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2. Should we reserve one node as "management" and only run LXCs on two?
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3. What's the Tailscale story — do we bind Corosync to LAN only or also Tailscale?
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## 7. Decision Points
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| Decision | Option A | Option B |
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|----------|----------|----------|
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| Cluster type | 3-node with quorum (recommended) | 2-node + witness (not recommended) |
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| HA level | Manual migration only | Full HA with auto-restart |
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| Storage | NFS only (current) | Add local Ceph later |
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| Resource reserve | 1 node mostly idle | Distribute evenly |
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---
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**Awaiting Commander Bobby review and approval.** |