手动启动，查看日志如下。
图片发自简书App
This system doesn't provide enough entropy to quickly generate high-quality random numbers.
Installing the rng-utils/rng-tools, jitterentropy or haveged packages may help.
On virtualized Linux environments, also consider using virtio-rng.
The service will not start until enough entropy has been collected.
解决办法:
yum 安装 rng-tools
并在init的ss启动脚本中，ss-server启动前添加一行执行语句rngd -r /dev/urandom
