Redis是NoSQL（No Only SQL，非关系型数据库）的一种，NoSQL是以Key-Value的形式存储数据。当前主流的分布式缓存技术有redis,memcached,ssdb,MongoDB等。既可以把redis理解为理解为缓存技术，因为它的数据都是缓存在内从中的；也可以理解为数据库，因为redis可以周期性的将数据写入磁盘或者把操作追加到记录文件中。而我个人更倾向理解为缓存技术，因为当今互联网应用业务复杂、高并发、大数据的特性，正是各种缓存技术引入最终目的。
关于redis与传统关系型数据的对比、redis与memcached的对比、redis的优缺点，在此将不介绍，因为都各有各的好处，只有结合了具体的业务场景，才能深刻体会它们之间的差别和优缺点。下面开始redis在Linux上的安装。
1)、下载redis安装包
下载地址：http://redis.io/
或者命令行下载：
[root@localhost ftpuser]# wget http://download.redis.io/releases/redis-3.2.0.tar.gz 1 12)、编译源程序
[root@localhost ftpuser]# tar zxvf redis-3.2.0.tar.gz [root@localhost ftpuser]# cd redis-3.2.0 [root@localhost redis-3.2.0]# make [root@localhost redis-3.2.0]# cd src && make install 1234 1234创建目录存放redis配置文件和命令文件
[root@localhost redis-3.2.0]# mkdir -p /usr/local/redis/conf [root@localhost redis-3.2.0]# mkdir -p /usr/local/redis/bin 12 12移动配置文件和命令文件到上面创建的地址
[root@localhost redis-3.2.0]# mv redis.conf /usr/local/redis/conf [root@localhost redis-3.2.0]# cd src [root@localhost src]# cp mkreleasehdr.sh redis-benchmark redis-check-aof redis-check-rdb redis-cli redis-server redis-sentinel redis-trib.rb /usr/local/redis/bin 123 123注：如果不移动，操作的redis.conf配置文件在redis的根目录，操作相关命令在根下的src下面
除此之外，一般还创建run、log、rdb、aof文件夹，分别用于存放运行进程id(pid)、log日志、持久化RDB方式二进制快照文件dump.rdb(持久化AOF方式数据文件appendonly.aof、集群节点配置文件nodes-6379.conf也都会生成到rdb这个文件夹中，与dump.rdb同目录存储)，这些都需要修改redis.conf配置文件中默认的路径。
运行端口pid以及日志log：
################################# GENERAL ##################################### # By default Redis does not run as a daemon. Use 'yes' if you need it. # Note that Redis will write a pid file in /var/run/redis.pid when daemonized. daemonize no # If you run Redis from upstart or systemd, Redis can interact with your # supervision tree. Options: # supervised no - no supervision interaction # supervised upstart - signal upstart by putting Redis into SIGSTOP mode # supervised systemd - signal systemd by writing READY=1 to $NOTIFY_SOCKET # supervised auto - detect upstart or systemd method based on # UPSTART_JOB or NOTIFY_SOCKET environment variables # Note: these supervision methods only signal "process is ready." # They do not enable continuous liveness pings back to your supervisor. supervised no # If a pid file is specified, Redis writes it where specified at startup # and removes it at exit. # # When the server runs non daemonized, no pid file is created if none is # specified in the configuration. When the server is daemonized, the pid file # is used even if not specified, defaulting to "/var/run/redis.pid". # # Creating a pid file is best effort: if Redis is not able to create it # nothing bad happens, the server will start and run normally. # pidfile /var/run/redis_6379.pid pidfile "/usr/local/redis/run/redis_6379.pid" # Specify the server verbosity level. # This can be one of: # debug (a lot of information, useful for development/testing) # verbose (many rarely useful info, but not a mess like the debug level) # notice (moderately verbose, what you want in production probably) # warning (only very important / critical messages are logged) loglevel notice # Specify the log file name. Also the empty string can be used to force # Redis to log on the standard output. Note that if you use standard # output for logging but daemonize, logs will be sent to /dev/null logfile "/usr/local/redis/log/redis.log" 1234567891011121314151617181920212223242526272829303132333435363738394041 1234567891011121314151617181920212223242526272829303132333435363738394041快照rdb：
################################ SNAPSHOTTING ################################ # # Save the DB on disk: # # save <seconds> <changes> # # Will save the DB if both the given number of seconds and the given # number of write operations against the DB occurred. # # In the example below the behaviour will be to save: # after 900 sec (15 min) if at least 1 key changed # after 300 sec (5 min) if at least 10 keys changed # after 60 sec if at least 10000 keys changed # # Note: you can disable saving completely by commenting out all "save" lines. # # It is also possible to remove all the previously configured save # points by adding a save directive with a single empty string argument # like in the following example: # # save "" save 900 1 save 300 10 save 60 10000 # By default Redis will stop accepting writes if RDB snapshots are enabled # (at least one save point) and the latest background save failed. # This will make the user aware (in a hard way) that data is not persisting # on disk properly, otherwise chances are that no one will notice and some # disaster will happen. # # If the background saving process will start working again Redis will # automatically allow writes again. # # However if you have setup your proper monitoring of the Redis server # and persistence, you may want to disable this feature so that Redis will # continue to work as usual even if there are problems with disk, # permissions, and so forth. stop-writes-on-bgsave-error yes # Compress string objects using LZF when dump .rdb databases? # For default that's set to 'yes' as it's almost always a win. # If you want to save some CPU in the saving child set it to 'no' but # the dataset will likely be bigger if you have compressible values or keys. rdbcompression yes # Since version 5 of RDB a CRC64 checksum is placed at the end of the file. # This makes the format more resistant to corruption but there is a performance # hit to pay (around 10%) when saving and loading RDB files, so you can disable it # for maximum performances. # # RDB files created with checksum disabled have a checksum of zero that will # tell the loading code to skip the check. rdbchecksum yes # The filename where to dump the DB dbfilename dump.rdb # The working directory. # # The DB will be written inside this directory, with the filename specified # above using the 'dbfilename' configuration directive. # # The Append Only File will also be created inside this directory. # # Note that you must specify a directory here, not a file name. # dir ./ dir "/usr/local/redis/rdb" 123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869 1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465666768693)、启动redis服务，主要有两种方式：
方式一：直接启动
#加上`&`号使redis以后台程序方式运行 [root@localhost src]# redis-server & 12 12方式二：指定配置文件启动
[root@localhost src]# redis-server ../redis.conf & 1 1如上，启动redis服务需要指定配置文件，也可以需要修改redis.conf文件，daemonize no —- >daemonize yes实现后台启动。 redis服务端默认链接端口是6379，最好也将IP绑定为本机IP。
4)、验证是否启动成功
[root@localhost ~]# ps -ef | grep redis #或者 [root@localhost ~]# netstat -tunpl | grep 6379 123 1235)、客户端连接
[root@localhost src]# redis-cli #远程连接方式 [root@localhost src]# redis-cli -h 127.0.0.1 -p 6379 redis> set foo bar OK redis> get foo "bar" 1234567 12345676)、停止redis服务
[root@localhost src]# redis-cli shutdown #或者 [root@localhost ~]# pkill redis-server #或者 [root@localhost ~]# kill -9 PID 12345 12345以上为转载内容，来源于：http://www.cnblogs.com/hjwublog/p/5637150.html
=============================分割线：验证上述过程(远程连接时)发现的问题：一波三折======================================
所抛出的异常已经给出了详细原因：
redis是在protected mode下运行的；经查询可知，在redis3.2之后，redis增加了protected mode模式，是为了禁止公网访问redis cache，加强redis安全。同时redis默认只允许本地访问。综合异常信息里面给出的解决方案，我选择方案2，修改redis.conf配置文件，将protected mode yes修改为no，同时将redis默认只允许本地访问的配置注释[# bind 127.0.0.1]，修改redis.conf内容如下：
################################## NETWORK ##################################### # By default, if no "bind" configuration directive is specified, Redis listens # for connections from all the network interfaces available on the server. # It is possible to listen to just one or multiple selected interfaces using # the "bind" configuration directive, followed by one or more IP addresses. # # Examples: # # bind 192.168.1.100 10.0.0.1 # bind 127.0.0.1 ::1 # # ~~~ WARNING ~~~ If the computer running Redis is directly exposed to the # internet, binding to all the interfaces is dangerous and will expose the # instance to everybody on the internet. So by default we uncomment the # following bind directive, that will force Redis to listen only into # the IPv4 lookback interface address (this means Redis will be able to # accept connections only from clients running into the same computer it # is running). # # IF YOU ARE SURE YOU WANT YOUR INSTANCE TO LISTEN TO ALL THE INTERFACES # JUST COMMENT THE FOLLOWING LINE. # ~~~~~~~~~~~~~~~~~~~~~~~~~~将可以访问的ip绑定注释掉~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ # bind 127.0.0.1 # Protected mode is a layer of security protection, in order to avoid that # Redis instances left open on the internet are accessed and exploited. # # When protected mode is on and if: # # 1) The server is not binding explicitly to a set of addresses using the # "bind" directive. # 2) No password is configured. # # The server only accepts connections from clients connecting from the # IPv4 and IPv6 loopback addresses 127.0.0.1 and ::1, and from Unix domain # sockets. # # By default protected mode is enabled. You should disable it only if # you are sure you want clients from other hosts to connect to Redis # even if no authentication is configured, nor a specific set of interfaces # are explicitly listed using the "bind" directive. # ~~~~~~~~~~~~~~~~~~~~~~~~~~将protected-mode yes修改为protected-mode no~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ # protected-mode yes protected-mode no 123456789101112131415161718192021222324252627282930313233343536373839404142434445 123456789101112131415161718192021222324252627282930313233343536373839404142434445或者直接把bind的地址更改为服务器本机ip，注意不是127.0.0.1的形式，是真实的ip，这样不用修改protected-mode 也没有关系，因为默认情况，127.0.0.1是受保护的ip，只能本机访问。
重启redis服务，尝试远程连接：
[root@localhost src]# redis-server [root@localhost src]# redis-cli -h 127.0.0.1 -p 6379 12 12注意：是不是发现结果是一样的，上面的异常依然存在，这个是因为启动redis的方式造成的。
按照方式一启动，修改redis.conf文件不起作用，需要本地登录redis客户端，然后采用异常里面提供的方案1，即通过命令修改，CONFIG SET protected-mode no，具体执行如下：
#启动redis服务 [root@localhost src]# redis-server #本地登录客户端 [root@localhost src]# redis-cli -p 6379 #命令修改protected-mode为no 127.0.0.1:6379> CONFIG SET protected-mode no #远程登录 [root@localhost src]# redis-cli -h 127.0.0.1 -p 6379 12345678 12345678如果就想通过修改redis.conf配置文件来实现远程登录(即按照异常里面的方案2操作)，那么启动redis服务的方式，就应该选择方式二，需要指定redis.conf配置启动，这个比较好理解，你修改了哪个，我就用哪个启动，具体操作如下：
#先修改redis.conf配置文件，修改内容看上面代码 #指定redis.conf配置文件启动redis服务 [root@localhost src]# redis-server ../redis.conf #远程登录 [root@localhost src]# redis-cli -h 127.0.0.1 -p 6379 12345 12345上面两种方式结果一切正常。
redis默认使用端口为6379，意思是说：使用redis-server、redis-cli、redis-cli shutdown都使用6379端口，如果将redis.conf端口修改为6389，然后执行以下操作：
#不能使用redis-server直接启动，否则redis.conf配置文件修改无效 #指定配置文件启动 [root@localhost src]# redis-server ../redis.conf 6081:M 25 Aug 11:02:21.488 * The server is now ready to accept connections on port 6389 [root@localhost src]# redis-cli Could not connect to Redis at 127.0.0.1:6379: Connection refused [root@localhost src]# redis-cli shutdown Could not connect to Redis at 127.0.0.1:6379: Connection refused 12345678910 12345678910因为默认使用了6379端口，所以此处需要为其显示指定修改后的6389端口：
#客户端登录 [root@localhost src]# redis-cli -p 6389 127.0.0.1:6389> #停止redis服务 [root@localhost src]# redis-cli -p 6389 shutdown 6081:M 25 Aug 11:02:21.488 * The server is now ready to accept connections on port 6389 6081:M 25 Aug 11:07:56.652 # User requested shutdown... 12345678 12345678远程连接默认是无权限认证的，添加权限认证，需修改redis.conf配置文件，内容如下：
################################## SECURITY ################################### # Require clients to issue AUTH <PASSWORD> before processing any other # commands. This might be useful in environments in which you do not trust # others with access to the host running redis-server. # # This should stay commented out for backward compatibility and because most # people do not need auth (e.g. they run their own servers). # # Warning: since Redis is pretty fast an outside user can try up to # 150k passwords per second against a good box. This means that you should # use a very strong password otherwise it will be very easy to break. # # ~~~~~~~~~~~~~~~~~~~~~~~~~~将requirepass foobared权限认证开放~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ # requirepass foobared requirepass foobared 12345678910111213141516 12345678910111213141516 #指定配置文件启动 [root@localhost src]# redis-server ../redis.conf #远程登录 [root@localhost src]# redis-cli -h 127.0.0.1 -p 6389 -a foobared 127.0.0.1:6389> 123456 123456除了在登录时通过 -a 参数制定密码外，还可以登录时不指定密码，而在执行操作前进行认证：
[root@localhost src]# redis-cli -h 127.0.0.1 -p 6389 127.0.0.1:6389> config get requirepass (error) NOAUTH Authentication required. 127.0.0.1:6389> auth foobared OK 127.0.0.1:6389> config get requirepass 1) "requirepass" 2) "foobared" 127.0.0.1:6389> 123456789 123456789注：(error) NOAUTH Authentication required.指的是开放了权限验证，但连接或者执行时没有使用密码。
抛出这样的异常，可以从一下几个方面去排查：
ping redis服务ip，是否可以ping通telnet redis端口，要确保redis服务正在使用的6379或者6389等端口有没有被防火墙屏蔽其它===============补充====================== 通常的配置如下：
//绑定服务器本地只是ip bind 192.168.1.222
//绑定端口号，默认6379 port 6381
//客户端连接超时时间，如果为，则永不超时 timeout 1000
//设置redis进程为守护进程启动，redis-server redis.conf & 效果一样 daemonize yes
//设置守护进程启动之后，保存进程号的文件位置 pidfile /usr/local/redis/master/6381/run/redis_6381.pid
//配置日志级别，debug、verbose、notice、warning loglevel debug
//配置日志文件存储地址，是一个文件 logfile “/usr/local/redis/master/6381/logs/redis.log”
//rdb持久化机制，主从配置中，一般主服务器关闭rdb持久化，从服务器负责持久化，一般使用aof代替rdb模式，将save注释即可 save 900 1 save 300 10 save 60 10000
//rdb持久化文件名称 dbfilename dump.rdb
//rdb持久化文件保存地址，aof持久化也是用这个地址 dir /usr/local/redis/master/6381/rdb
//将当前服务作为从服务器，隶属的主服务如下，如果是开启了集群模式，手动配置主从关系导致无法启动，需要将slaveof注释掉，由redis-trib负责分配主从关系 slaveof 192.168.1.222 6379
//如果主服务有密码的话，配置主服务密码，集群模式，需要考虑主从切换的问题，所以建议主从密码一致或不启用 masterauth 123
//从服务的读写能力，默认只读，主服务会忽略这个配置 slave-read-only yes
//当前服务启用密码验证，集群模式，需要考虑主从切换的问题，所以建议主从密码一致或不启用 requirepass 123
//启用aof持久化机制，推荐使用aof模式替换rdb模式 appendonly yes
//aof持久化机制的文件名称 appendfilename “appendonly.aof”
//aof持久化采用的默认机制，每秒持久化一次，还有always和no两种 appendfsync everysec
//启动集群模式，注意不要手动配置主从关系 cluster-enabled yes
//指定集群节点超时时间 cluster-node-timeout 5000
//指定集群节点配置文件，默认使用的路径为上面配置的dir cluster-config-file nodes-6381.conf
================分割线=============
主从配置文件路径参考： /usr/local/redis/master/6379 /usr/local/redis/slave/7031 –redis.conf 服务配置文件 –bin 负责存放命令文件 –rdb 负责存放持久化文件 –logs 负责存放日志 –run 负责存放进程id
==============分割线===============
集群配置文件路径参考：
/usr/local/redis-cluster/ --6379/ --6380/ --6381/ --7031/ --7032/ --7033/ --redis.conf 服务配置文件 --bin 负责存放命令文件 --rdb 负责存放持久化文件 --logs 负责存放日志 --run 负责存放进程id