# [Know Issue] 使用 tiup scale-out 方式部署 drainer 失败

## Key Words

tiup, drainer, initial_commit_ts, startup, failed

## Description

执行 tiup cluster scale-out tidb-prd scale-out_drainer_tidb.yaml 命令进行 drainer 的部署失败，tiup 命令返回报错如下：

```log
Error: failed to start drainer: failed to start: xxx.xxx.xxx.xxx drainer-8251.service, please check the instance's log(/data/tidb-deploy/drainer-8251/log) for more detail.: timed out waiting for port 8251 to be started after 2m0s
```

查看 drainer 日志发现 drainer 启动的时候报错，无法识别参数 initial_commit_ts，详细报错内容：

```log
[2022/10/25 14:47:55.512 +08:00] [FATAL] [main go:39] ["verifying flags failed, See 'drainer - -help'."] [error="component drainer's config file conf/drainer.toml contained unknown config uration options: initial_commit_ts"] [errorVerl bose="component drainer's config file conf/drainer.toml contained unknown configuration options: initial committs\ngithub.com/pingcap/tidb- binlog/pkg/util.strictDecodeFile\n\t/home/jenk.ns/agent/workspace/build-common/go/src/github.c om/pingcap/tidb-binlog/pkg/util/util.go:209\ngit hub.com/pingcap/tidb-binlog/drainer(*Config).configFromFile\n\t/home/jenkins/agent/workspace/buildcommon/go/src/github.com/pingcap/tidb- binlog/drainer/config.go:348\ngithub.com/pingcap/tidb-binlog7drainer (*Config).Parse\n\t/hom e/jenkins/agent/workspace/build-common/go/src/( jithub.com/pingcap/tidb-binlog/drainer/config.go:261\nmain.main\n\t/home/jenkins/agent/workspace/build-common/go/src/github.com/pingcap/tidb -binlog/cmd/drainer/main.go:38\nruntime.main\n t/usr/local/go/src/runtime/proc.go:225\nruntime goexit\n\t/usr/local/go/src/runtime/asm amd64.s:1371"] [stadk="mainmaininvtyhorejenkins/a gent/workspace/buildcommon/go/src/github.com/p pingcap/tidb-binlog/cmd/drainer/main.go:39\nrunt ime.main\n\t/usr/local/go/src/runtime/proc.go:2225" ]

```

## Root Cause

tiup 工具[缺陷](https://github.com/pingcap/tiup/issues/1825)，生成 initial_commit_ts 带有下划线形式的参数名 config 文件，导致 drainer 无法识别而启动失败。

## Diagnostic Steps

N/A

## Resolution

升级 tiup 到 v1.9.2 及以后版本（建议默认升级到最新版本）。

## Workaround

N/A

## Affected Versions

<v1.9.2