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Systemd 服务创建符号链接

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Systemd 服务创建符号链接

我希望 Systemd 管理符号链接的存在。符号链接应存在于/var/run/mysqld/mysqld.sock并指向/var/run/proxysql/mysqld.sock。原因显而易见/有争议（我不会深入讨论）。让我们忽略这些细节，专注于所请求的解决方案。

到目前为止我已经创建了这个单元文件/usr/lib/systemd/system/mysqldsocket.service：

[Unit]
Description=Create a symlink to the ProxySQL MySQL UNIX socket
After=network.target

[Service]
Type=oneshot
RuntimeDirectory=mysqld
RuntimeDirectoryMode=0775
ExecStart=/usr/bin/ln -s /var/run/proxysql/mysqld.sock /var/run/mysqld/mysqld.sock
ExecStop=rm -f /var/run/mysqld/mysqld.sock
RemainAfterExit=yes

[Install]
WantedBy=multi-user.target

运行systemctl start mysqldsocket.service确实会创建符号链接并将systemctl stop mysqldsocket.service其删除。但是 systemd 不知道该文件是否真的存在，systemctl status mysqldsocket.service并不总是与实际情况相符。

# systemctl start mysqldsocket.service
# rm /var/run/mysqld/mysqld.sock
# systemctl status mysqldsocket.service 
● mysqldsocket.service - Create a symlink to the ProxySQL MySQL UNIX socket
     Loaded: loaded (/lib/systemd/system/mysqldsocket.service; disabled; vendor preset: enabled)
     Active: active (exited) since Sun 2022-04-03 22:21:46 UTC; 14s ago
    Process: 750220 ExecStart=/usr/bin/ln -s /var/run/proxysql/mysqld.sock /var/run/mysqld/mysqld.sock (code=exited, status=0/SUCCE>
   Main PID: 750220 (code=exited, status=0/SUCCESS)

我可以添加一些内容来/usr/lib/systemd/system/mysqldsocket.service告诉 systemd 验证符号链接确实存在并据此报告正确的状态吗？

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