Failover multi-regione con una mesh WireGuard

# 01 Scegli tre domini di guasto indipendenti

Different countries, ideally different transit mixes. Amsterdam, Ashburn and Singapore is the classic triangle. Three is the minimum for quorum — two gives you a split-brain problem rather than redundancy.

# 02 Costruisci la mesh

Each node gets a stable private address. Every node peers with every other node; with three nodes that is three tunnels.

# node A — /etc/wireguard/mesh.conf
[Interface]
Address = 10.10.0.1/24
ListenPort = 51821
PrivateKey = <A private>

[Peer]                       # node B
PublicKey = <B public>
Endpoint = b.example.net:51821
AllowedIPs = 10.10.0.2/32
PersistentKeepalive = 25

[Peer]                       # node C
PublicKey = <C public>
Endpoint = c.example.net:51821
AllowedIPs = 10.10.0.3/32
PersistentKeepalive = 25

# 03 Collega i servizi solo alla mesh

The database, the cache and the internal API should listen on 10.10.0.x, never on the public address. This removes an entire class of exposure without a single firewall rule.

# 04 Replica il database in modo appropriato

Synchronous replication across regions is impractical — a 160 ms round trip becomes the floor for every write. Use asynchronous replication across regions and know your recovery point objective.

# 05 Health check a livello DNS

Short TTLs plus health-checked failover records, or anycast if your regions support it. Then run a failure drill: kill a region deliberately, on a weekday, while you are watching.