Redis高級(jí)實(shí)用特性：安全性與主從復(fù)制
安全性
設(shè)置客戶端連接后進(jìn)行任何其他指定前需要使用的密碼。
警告：因?yàn)閞edis速度相當(dāng)快，所以在一臺(tái)比較好的服務(wù)器下，一個(gè)外部的用戶可以在一秒鐘進(jìn)行150K次的密碼嘗試，這意味著你需要指定非常非常強(qiáng)大的密碼來(lái)防止暴力破解。
- # requirepass foobared
- requirepass beijing
下面我們做一個(gè)實(shí)驗(yàn)，說(shuō)明redis的安全性是如何實(shí)現(xiàn)的。
我們?cè)O(shè)置了連接的口令是beijing
那么們啟動(dòng)一個(gè)客戶端試一下:
- [root@localhost redis-2.2.12]# src/redis-cli
- redis 127.0.0.1:6379> keys *
- (error) ERR operation not permitted
- redis 127.0.0.1:6379>
說(shuō)明權(quán)限太小，我們可以當(dāng)前的這個(gè)窗口中設(shè)置口令
- redis 127.0.0.1:6379> auth beijing
- OK
- redis 127.0.0.1:6379> keys *
- 1) "name"
- redis 127.0.0.1:6379>
我們還可以在連接到服務(wù)器期間就指定一個(gè)口令，如下:
- [root@localhost redis-2.2.12]# src/redis-cli -a beijing
- redis 127.0.0.1:6379> keys *
- 1) "name"
- redis 127.0.0.1:6379>
可以看到我們?cè)谶B接的時(shí)候就可以指定一個(gè)口令。
主從復(fù)制
Redis主從復(fù)制配置和使用都非常簡(jiǎn)單。通過(guò)主從復(fù)制可以允許多個(gè)slave server擁有和master server相同的數(shù)據(jù)庫(kù)副本。
1、redis主從復(fù)制特點(diǎn):
(1)、master可以擁有多個(gè)slave
(2)、多個(gè)slave可以連接同一個(gè)master外，還可以連接到其他slave
(3)、主從復(fù)制不會(huì)阻塞master，在同步數(shù)據(jù)時(shí)，master可以繼續(xù)處理client請(qǐng)求
(4)、提高系統(tǒng)的伸縮性
2、redis主從復(fù)制過(guò)程:
當(dāng)配置好slave后，slave與master建立連接，然后發(fā)送sync命令。無(wú)論是第一次連接還是重新連接，master都會(huì)啟動(dòng)一個(gè)后臺(tái)進(jìn)程，將數(shù)據(jù)庫(kù)快照保存到文件中，同時(shí)master主進(jìn)程會(huì)開(kāi)始收集新的寫(xiě)命令并緩存。后臺(tái)進(jìn)程完成寫(xiě)文件后，master就發(fā)送文件給slave，slave將文件保存到硬盤(pán)上，再加載到內(nèi)存中，接著master就會(huì)把緩存的命令轉(zhuǎn)發(fā)給slave，后續(xù)master將收到的寫(xiě)命令發(fā)送給slave。如果master同時(shí)收到多個(gè)slave發(fā)來(lái)的同步連接命令，master只會(huì)啟動(dòng)一個(gè)進(jìn)程來(lái)寫(xiě)數(shù)據(jù)庫(kù)鏡像，然后發(fā)送給所有的slave。
3、如何配置
配置slave服務(wù)器很簡(jiǎn)單，只需要在slave的配置文件中加入如下配置
- slaveof 192.168.1.1 6379 #指定master的ip和端口
下面我們做一個(gè)實(shí)驗(yàn)來(lái)演示如何搭建一個(gè)主從環(huán)境:
- # slaveof <masterip> <masterport>
- slaveof localhost 6379
我們?cè)谝慌_(tái)機(jī)器上啟動(dòng)主庫(kù)(端口6379)，從庫(kù)(端口6378)
啟動(dòng)后主庫(kù)控制臺(tái)日志如下:
- [root@localhost redis-2.2.12]# src/redis-server redis.conf
- [7064] 09 Aug 20:13:12 * Server started, Redis version 2.2.12
- [7064] 09 Aug 20:13:12 # WARNING overcommit_memory is set to 0! Background save may fail under low memory condition. To fix this issue add 'vm.overcommit_memory = 1' to /etc/sysctl.conf and then reboot or run the command 'sysctl vm.overcommit_memory=1' for this to take effect.
- [7064] 09 Aug 20:13:12 * The server is now ready to accept connections on port 6379
- [7064] 09 Aug 20:13:13 - 0 clients connected (0 slaves), 539512 bytes in use
- [7064] 09 Aug 20:13:18 - 0 clients connected (0 slaves), 539512 bytes in use
- [7064] 09 Aug 20:13:20 - Accepted 127.0.0.1:37789
- [7064] 09 Aug 20:13:20 * Slave ask for synchronization
- [7064] 09 Aug 20:13:20 * Starting BGSAVE for SYNC
- [7064] 09 Aug 20:13:20 * Background saving started by pid 7067
- [7067] 09 Aug 20:13:20 * DB saved on disk
- [7064] 09 Aug 20:13:20 * Background saving terminated with success
- [7064] 09 Aug 20:13:20 * Synchronization with slave succeeded
- [7064] 09 Aug 20:13:23 - 0 clients connected (1 slaves), 547380 bytes in use
啟動(dòng)后從庫(kù)控制臺(tái)日志如下:
- [root@localhost redis-2.2.12]# src/redis-server redis.slave
- [7066] 09 Aug 20:13:20 * Server started, Redis version 2.2.12
- [7066] 09 Aug 20:13:20 # WARNING overcommit_memory is set to 0! Background save may fail under low memory condition. To fix this issue add 'vm.overcommit_memory = 1' to /etc/sysctl.conf and then reboot or run the command 'sysctl vm.overcommit_memory=1' for this to take effect.
- [7066] 09 Aug 20:13:20 * The server is now ready to accept connections on port 6378
- [7066] 09 Aug 20:13:20 - 0 clients connected (0 slaves), 539548 bytes in use
- [7066] 09 Aug 20:13:20 * Connecting to MASTER...
- [7066] 09 Aug 20:13:20 * MASTER <-> SLAVE sync started: SYNC sent
- [7066] 09 Aug 20:13:20 * MASTER <-> SLAVE sync: receiving 10 bytes from master
- [7066] 09 Aug 20:13:20 * MASTER <-> SLAVE sync: Loading DB in memory
- [7066] 09 Aug 20:13:20 * MASTER <-> SLAVE sync: Finished with success
- [7068] 09 Aug 20:13:20 * SYNC append only file rewrite performed
- [7066] 09 Aug 20:13:20 * Background append only file rewriting started by pid 7068
- [7066] 09 Aug 20:13:21 * Background append only file rewriting terminated with success
- [7066] 09 Aug 20:13:21 * Parent diff flushed into the new append log file with success (0 bytes)
- [7066] 09 Aug 20:13:21 * Append only file successfully rewritten.
- [7066] 09 Aug 20:13:21 * The new append only file was selected for future appends.
- [7066] 09 Aug 20:13:25 - 1 clients connected (0 slaves), 547396 bytes in use
我們?cè)谥鲙?kù)上設(shè)置一對(duì)鍵值對(duì)
- redis 127.0.0.1:6379> set name HongWan
- OK
- redis 127.0.0.1:6379>
在從庫(kù)上取一下這個(gè)鍵
- redis 127.0.0.1:6378> get name
- "HongWan"
- redis 127.0.0.1:6378>
說(shuō)明主從是同步正常的.
那么我們?nèi)绾闻袛嗄膫€(gè)是主哪個(gè)是從呢?我們只需調(diào)用info這個(gè)命令就可以得到主從的信息了,我們?cè)趶膸?kù)上執(zhí)行info命令
- redis 127.0.0.1:6378> info
- .
- .
- .
- role:slave
- master_host:localhost
- master_port:6379
- master_link_status:up
- master_last_io_seconds_ago:10
- master_sync_in_progress:0
- db0:keys=1,expires=0
- redis 127.0.0.1:6378>
里面有一個(gè)角色標(biāo)識(shí),來(lái)判斷是主庫(kù)還是從庫(kù),對(duì)于本例是一個(gè)從庫(kù)，同時(shí)還有一個(gè)master_link_status用于標(biāo)明主從是否異步，如果此值=up，說(shuō)明同步正常;如果此值=down，說(shuō)明同步異步;
db0:keys=1,expires=0， 用于說(shuō)明數(shù)據(jù)庫(kù)有幾個(gè)key,以及過(guò)期key的數(shù)量。
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