The access layer of AnalyticDB for MySQL uses full redundancy and a Multi-Master architecture to eliminate single points of failure and maintain service availability when individual nodes fail.
Architecture components
The access layer consists of multiple frontend nodes, all attached to the same Server Load Balancer (SLB) instance.
| Component | Role |
|---|---|
| Frontend nodes | Serve queries and hold an up-to-date routing table for storage and compute nodes |
| SLB instance | Distributes incoming connections across all frontend nodes |
| Master node | One frontend node elected as master; manages heartbeats and pushes routing updates to the other nodes |
Because every frontend node maintains a current routing table, each frontend node can equally serve queries.
Failover behavior
When a frontend node goes down, SLB automatically reroutes its connections to the remaining healthy nodes without affecting your business.
Coverage
The Multi-Master architecture protects against individual frontend node failures. SLB detects the failure and redirects traffic to other frontend nodes, implementing high availability at the access layer.
This failover applies to the access layer only. For storage and compute layer availability, see the relevant architecture documentation.