在dcos环境下，rexray服务的默认配置文件为/opt/mesosphere/etc/rexray.conf，而其服务文件则是
/etc/systemd/system/dcos-rexray.service。
# vim /etc/systemd/system/dcos-rexray.service
[Unit]
Description=REX-Ray: A vendor agnostic storage orchestration engine
[Service]
StartLimitInterval=0
Restart=always
RestartSec=15
LimitNOFILE=16384
EnvironmentFile=/opt/mesosphere/environment
EnvironmentFile=/opt/mesosphere/etc/proxy.env
Environment=REXRAY_HOME=/
# REX-Ray fails to clean up stale lock files by itself.
ExecStartPre=/bin/rm -f /var/run/libstorage/lsx.lock
# Allow REX-Ray configuration to be changed during upgrade.
ExecStartPre=/bin/cp /opt/mesosphere/etc/rexray.conf /etc/rexray/config.yml
ExecStart=/opt/mesosphere/packages/rexray--da7f17f8a4b772c0bac3f8d289a08abd4ff272b4/bin/rexray start -f
根据该服务文件可看出，其基本功能就是拷贝/opt/mesosphere/etc/rexray.conf到rexray的配置文件/etc/rexray/config.yml中，然后启动rexray服务。
启动rexray服务：
# systemctl start dcos-rexray
