报错信息：

nginx: [alert] failed to load the 'resty.core' module (https://github.com/openresty/lua-resty-core); ensure you are using an OpenResty release from openresty.org/en/download.html (reason: module 'resty.core' not found:
        no field package.preload['resty.core']
        no file './resty/core.lua'
        no file '/usr/local/share/luajit-2.1.0-beta3/resty/core.lua'
        no file '/usr/local/share/lua/5.1/resty/core.lua'
        no file '/usr/local/share/lua/5.1/resty/core/init.lua'
        no file './resty/core.so'
        no file '/usr/local/lib/lua/5.1/resty/core.so'
        no file '/usr/local/lib/lua/5.1/loadall.so'
        no file './resty.so'
        no file '/usr/local/lib/lua/5.1/resty.so'
        no file '/usr/local/lib/lua/5.1/loadall.so') in /usr/local/nginx/conf/nginx.conf:222

原因分析：

找不到lualib库和resty模块，默认到/usr/local/lib/ 去找lualib，然而在编译安装OpenResty时lualib库默认放到/usr/local/openresty/lualib
 $ ln -s /usr/local/openresty/lualib /usr/local/lib/lua $ ln -s /usr/local/openresty/lualib/resty /usr/local/lib

如果是之前已配置“ln -s /usr/local/openresty/lualib/resty /usr/local/lib”，本次执行“/usr/local/nginx/sbin/nginx -c /usr/local/nginx/conf/nginx.conf”仍报上述错误，则删除已有的软连接，重新执行“ln -s /usr/local/openresty/lualib/resty /usr/local/lib”

即：

 # cd /usr/local/lib
 # ls
libluajit-5.1.a  libluajit-5.1.so  libluajit-5.1.so.2  libluajit-5.1.so.2.1.0  lua  pkgconfig  resty
 # rm -rf ./resty
 # ln -s /usr/local/openresty/lualib/resty /usr/local/lib
 # /usr/local/nginx/sbin/nginx -c /usr/local/nginx/conf/nginx.conf