WolfStack Keepalived HA Setup

Files

File	Node	Priority	Intended State
`keepalived-node1-primary.conf`	192.168.5.214	150	MASTER
`keepalived-node2-secondary.conf`	`192.168.15.182`	BACKUP	130
`keepalived-node3-tertiary.conf`	192.168.50.41	110	BACKUP

Shared VIP: 192.168.63.254 on interface eth0

Quick Install (per node)

sudo apt install keepalived netcat-openbsd -y
sudo cp keepalived-nodeX-*.conf /etc/keepalived/keepalived.conf
sudo systemctl enable keepalived --now
sudo systemctl status keepalived

Watch the syslog:

sudo journalctl -u keepalived -f

Network Confirmation

All three nodes (.5.x, .50.x) and the VIP (.63.254) fall within the same 192.168.0.0/18 network (192.168.0.0 – 192.168.63.255). This means they share Layer 2/L3 broadcast domain and VRRP unicast failover works cleanly across all nodes — no VLAN bridging or routing tricks required. ✅

What Happens In Practice

Scenario	Outcome
Node 1 dies, Node 2 healthy	VIP moves to Node 2 ✅
Node 1 + Node 2 die, Node 3 alive	VIP moves to Node 3 ✅ (clients reach it directly)
Node 3 is primary but 1 & 2 alive	Node 3 will NOT win because priority 110 < 150 / 130 ✅
All 3 nodes lose peer connectivity	Split-brain risk — each may claim VIP. Use fencing/STONITH if this is production-critical.

Track Script Explained

script "/usr/bin/nc -z -w 2 127.0.0.1 8553"

This checks whether the local WolfStack UI (port 8553) is accepting TCP connections.

If WolfStack crashes / stops on the MASTER, keepalived subtracts weight -40 from that node's priority.
Priority drops from 150 → 110, which is below Node 2 (130). Node 2 promotes to MASTER and takes the VIP.
If Node 1 comes back online and WolfStack is healthy, its priority returns to 150. The VIP will move back unless you keep nopreempt.

Preempt Behaviour

Setting	Behaviour
`nopreempt` present	Once VIP is on a backup node, it stays there even when higher-priority node recovers. Good for stability. Manual failback required.
`nopreempt` removed	Highest priority node reclaims VIP automatically. Good for deterministic primary/secondary but causes brief flap.

⚠️ WolfStack-Specific Caveats (from research)

No native UI HA: WolfStack's web UI is single-node. If you point browsers at the VIP and Node 2 takes over, users must re-authenticate (sessions are local to each node).
No reverse-proxy awareness: The UI doesn't have a "behind proxy" setting. If you terminate SSL on a proxy and forward to http://backend:8553, you may hit mixed-content or CSP issues.
WebSockets: The dashboard uses websockets for the terminal and real-time graphs. Make sure your proxy (or keepalived direct-access path) supports websocket upgrades if not hitting the VIP directly.
WolfProxy: WolfStack ships a sibling WolfProxy (NGINX-compatible), but that is a separate reverse proxy for other services, not for making the WolfStack UI highly available.

Suggested Topology

                 Clients / Browsers
                         |
                         v
              +---------------------+
              |   VIP: 192.168.63.254  |
              |  (keepalived floating)  |
              +----------+----------+
                         |
        +----------------+----------------+
        |                                 |
   Node 1 (MASTER)                   Node 2 (BACKUP)
 192.168.5.214:8553               192.168.15.182:8553
   priority 150                      priority 130
        |                                 |
     WolfStack                       WolfStack
     WolfNet Mesh                      WolfNet Mesh
        +------------+ 192.168.50.41 +---+
                     Node 3 (BACKUP)
                    priority 110
                   (same VLAN?)

Testing Failover

From any client, curl -k https://192.168.63.254:8553 should show the WolfStack UI.
On the MASTER node: sudo systemctl stop wolfstack (simulating WolfStack crash).
Watch journalctl -u keepalived -f on Node 2 — it should promote to MASTER within ~6 seconds (3 x 2s intervals).
ip addr show eth0 on Node 2 should now show 192.168.63.254/32.
Client traffic should continue via the VIP.
Restart WolfStack on Node 1. If nopreempt is enabled, VIP stays on Node 2. If removed, VIP moves back to Node 1.

Rollback

sudo systemctl stop keepalived
sudo ip addr del 192.168.63.254 dev eth0   # if needed manually
sudo systemctl disable keepalived

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