首次在阿里云服务器上安装的Redis，应用连接报错了，如下图：

org.springframework.data.redis.RedisSystemException: Redis exception; nested exception is io.lettuce.core.RedisException: io.lettuce.core.RedisConnectionException: DENIED Redis is running in protected mode because protected mode is enabled, no bind address was specified, no authentication password is requested to clients. In this mode connections are only accepted from the loopback interface. If you want to connect from external computers to Redis you may adopt one of the following solutions: 1) Just disable protected mode sending the command 'CONFIG SET protected-mode no' from the loopback interface by connecting to Redis from the same host the server is running, however MAKE SURE Redis is not publicly accessible from internet if you do so. Use CONFIG REWRITE to make this change permanent. 2) Alternatively you can just disable the protected mode by editing the Redis configuration file, and setting the protected mode option to 'no', and then restarting the server. 3) If you started the server manually just for testing, restart it with the '--protected-mode no' option. 4) Setup a bind address or an authentication password. NOTE: You only need to do one of the above things in order for the server to start accepting connections from the outside.

问题排查：
1、ps -ef|grep redis 查看Redis服务是否正常启动

2、telnet看下是否能够ping通

3、查看Redis中redis.conf

redis.conf 文件修改以下内容：

1、# bind 127.0.0.1  防止远程连接不上
2、daemonize  yes  #后台运行
3、protected-mode no #关闭保护模式

然后重启即可

./redis-server ../redis.conf  #根据配置文件启动