# rpc错误：代码=不可用 描述=服务器当前正在关闭

- **ID:** `go/grpc-unavailable-server-shutdown`
- **领域:** go
- **类别:** network_error
- **验证级别:** ai_generated
- **修复率:** 80%

## 根因

gRPC服务器正在优雅关闭过程中，不接受新请求。

## 版本兼容性

| 版本 | 状态 | 引入 | 弃用 |
|------|------|------|------|
| 1.0 | active | — | — |
| 1.1 | active | — | — |

## 解决方案

1. **Implement retry with backoff to wait for the server to restart.** (80% 成功率)
   ```
   for i := 0; i < 5; i++ {
    resp, err := client.SomeRPC(ctx, req)
    if err == nil { return resp }
    if status.Code(err) != codes.Unavailable { return err }
    time.Sleep(time.Duration(1<<i) * time.Second)
}
   ```
2. **Use a load balancer to redirect requests to healthy instances.** (85% 成功率)
   ```
   Configure a load balancer that detects server health and routes traffic away from shutting down instances.
   ```

## 无效尝试

- **Retry the request immediately.** — The server is still shutting down; it may take some time to become available again. (90% 失败率)
- **Force the server to stop shutdown.** — Shutdown is initiated by the server; clients cannot override it. (100% 失败率)