Multi-region failover with a WireGuard mesh

# 01 Choose three independent failure domains

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 Build the 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 Bind services to the mesh only

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 适当复制数据库

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 在DNS层进行健康检查

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.