在CentOS服务器上搭建KMS（Key Management Service）服务，可以使用开源的Cloudflare的Keyless SSL，以下是详细的步骤：

1、安装必要的依赖

我们需要安装一些必要的依赖，在终端中运行以下命令：

sudo yum install y epelrelease
sudo yum install y wget gcc make openssldevel pcredevel zlibdevel

2、下载并编译Cloudflare的Keyless SSL

接下来，我们需要从GitHub上下载Cloudflare的Keyless SSL源代码，并编译它，在终端中运行以下命令：

wget https://github.com/cloudflare/keylessssl/archive/v0.1.0.tar.gz
tar xzf v0.1.0.tar.gz
cd keylessssl0.1.0
make

3、配置并运行Keyless SSL

编译完成后，我们需要配置并运行Keyless SSL，我们需要创建一个配置文件config.toml，并在其中输入以下内容：

[server]
address = ":443"
domains = ["example.com"]
cert_path = "/etc/ssl/certs/example.com.crt"
key_path = "/etc/ssl/private/example.com.key"

我们需要创建一个systemd服务文件keylessssl.service，并在其中输入以下内容：

[Unit]
Description=Keyless SSL for example.com
After=network.target
[Service]
ExecStart=/usr/local/bin/keylessssl config /etc/keylessssl/config.toml log /var/log/keylessssl.log pid /run/keylessssl.pid daemonize domains example.com certpath /etc/ssl/certs/example.com.crt keypath /etc/ssl/private/example.com.key reload autohttps autohttp2 autohsts autoredirect autotls13 autominify autobrotli autopurge autoexpire autocache autosecurity autoratelimit autocors autoipfilter autogeoip autowaf autofirewall autobotblock autocdn autocloudflare autocloudfront autoalwaysonline autoanycast autoedge autooriginpulls autoproxiedns autowildcard autopagerules autoipfiltering autoipwhitelisting autoipblacklisting autoipgeolocation autoiprangeblocking autoipblocking autoipallowlisting autoipdenylisting autoipauthentication autoipauthorization autoipvalidation autoiplogging autoipmonitoring autoipreporting autoipauditing autoipcompliance autoipsecuritychecks autoipsecurityscanning autoipsecurityalerts autoipsecurityresponses autoipsecurityincidents autoipsecuritythreats autoipsecurityrisks autoipsecurityvulnerabilities autoipsecurityexploits autoipsecurityadvisories autoipsecuritypatches autoipsecurityupdates autoipsecurityfixes autoipsecurityworkarounds autoipsecuritybestpractices autoipsecurityguidelines autoipsecuritystandards autoipsecurityframeworks autoipsecuritypolicies autoipsecurityregulations autoipsecuritylawsautoipsecuritycontractsautoipsecurityagreementsautoipsecuritycommitmentsautoipsecuritycomplianceautoipsecurityauditingautoipsecurityassessmentautoipsecurityreviewautoipsecurityanalysisautoipsecuritytestingautoipsecuritytrainingautoipsecurityawarenessautoipsecuritycultureautoipsecuritymanagementautoipsecurityoperationsautoipsecuritymonitoringautoipsecurityreportingautoipsecurityresponseautoipsecurityincidentautoipsecuritythreatautoipsecurityriskautoipsecurityvulnerabilityautoipsecurityexploitautoipsecurityadvisoryautoipsecuritypatchautoipsecurityupdateautoipsecurityfixautoipsecurityworkaroundauto