新搭建的环境。启动需要耗费5分钟以上。。网上找了一堆资料总结一下：
步骤1:
yum
install rng-tools
步骤2:
systemctl
start rngd
步骤3:
cp /usr/lib/systemd/
system/rngd.service /etc/systemd/
system
步骤4:
vim /etc/systemd/
system/rngd.service
步骤5:
修改其中对应的为：
ExecStart
=/sbin/rngd
-f -r /dev/urandom
步骤6:
systemctl daemon
-reload
步骤7:
systemctl restart rngd
