1. 安装依赖包

[root@rpi3 ~]# yum -y install gc gcc gcc++ gcc-c++ wget make libxml2  libxml2-devel  openssl  openssl-devel  curl-devel  libjpeg-devel  libpng-devel freetype-devel bison autoconf openldap-devel pcre-devel zlib-devel

1. 需要安装python, 2.7以上版本

2. 下载 letsencrypt   git clone https://github.com/letsencrypt/letsencrypt