Redis-Sentinel是官方推薦的高可用解決方案,當redis在做master-slave的高可用方案時,假如master宕機了,redis本身(以及其很多客戶端)都沒有實現自動進行主備切換,而redis-sentinel本身也是獨立運行的進程,可以部署在其他與redis集群可通訊的機器中監控... ...
Redis-Sentinel是官方推薦的高可用解決方案,當redis在做master-slave的高可用方案時,假如master宕機了,redis本身(以及其很多客戶端)都沒有實現自動進行主備切換,而redis-sentinel本身也是獨立運行的進程,可以部署在其他與redis集群可通訊的機器中監控redis集群。
v哨兵作用
監控(Monitoring): 哨兵(sentinel) 會不斷地檢查你的Master和Slave是否運作正常。 提醒(Notification):當被監控的某個Redis節點出現問題時, 哨兵(sentinel) 可以通過 API 向管理員或者其他應用程式發送通知。 自動故障遷移(Automatic failover):當一個Master不能正常工作時,哨兵(sentinel) 會開始一次自動故障遷移操作,它會將失效Master的其中一個Slave升級為新的Master, 並讓失效Master的其他Slave改為複製新的Master;當客戶端試圖連接失效的Master時,集群也會向客戶端返回新Master的地址,使得集群可以使用現在的Master替換失效Master。Master和Slave伺服器切換後,Master的redis.conf、Slave的redis.conf和sentinel.conf的配置文件的內容都會發生相應的改變,即,Master主伺服器的redis.conf配置文件中會多一行slaveof的配置,sentinel.conf的監控目標會隨之調換。圖解
v工作機制
Redis提供了sentinel(哨兵)機制,通過sentinel模式啟動redis後,自動監控master/slave的運行狀態,基本原理是:心跳機制+投票裁決 。每個sentinel會向其它sentinal、master、slave定時發送消息,以確認對方是否“活”著,如果發現對方在指定時間(可配置)內未回應,則暫時認為對方已掛(所謂的“主觀認為宕機” Subjective Down,簡稱SDOWN)。
若”哨兵群”中的多數sentinel,都報告某一master沒響應,系統才認為該master”徹底死亡”(即:客觀上的真正down機,Objective Down,簡稱ODOWN),通過一定的vote演算法,從剩下的slave節點中,選一臺提升為master,然後自動修改相關配置。
vredis-sentinel環境搭建
搭建哨兵環境之前,需要先安裝Redis,若你還沒有安裝Redis,可以先看這裡《centos安裝Redis》
1.0 在/usr/local/ 下新建一個目錄redis-sentinelmkdir /usr/local/redis-sentinel
1.1 在新目錄下簡7個目錄mkdir /usr/local/redis-sentinel/{7501,7502,7503,7504,7505,7506,7507}
1.2 依次將redis安裝目錄下的reids.conf,拷貝到前4個目錄下cp /root/redis-5.0.2/redis.conf /usr/local/redis-sentinel/7501/redis-7501.conf
1.3 依次修改新拷貝的4個redis.conf文件內容
daemonize yes
pidfile /var/run/redis_7501.pid
port 7501
# bind 127.0.0.1 可選,預設就處理所有請求。
logfile "./redis-7501.log"
dir "/usr/local/redis-sentinel/7501"
#redis配置密碼的話,需要以下配置
#masterauth "123456"
#requirepass "123456"
appendonly yes
1.4 redis.conf詳細介紹
##redis配置詳解 # Redis configuration file example. # # Note that in order to read the configuration file, Redis must be # started with the file path as first argument: # # ./redis-server /path/to/redis.conf # Note on units: when memory size is needed, it is possible to specify # it in the usual form of 1k 5GB 4M and so forth: # # 1k => 1000 bytes # 1kb => 1024 bytes # 1m => 1000000 bytes # 1mb => 1024*1024 bytes # 1g => 1000000000 bytes # 1gb => 1024*1024*1024 bytes # # units are case insensitive so 1GB 1Gb 1gB are all the same. ################################## INCLUDES ################################### ################################## 包含 ################################### # Include one or more other config files here. This is useful if you # have a standard template that goes to all Redis servers but also need # to customize a few per-server settings. Include files can include # other files, so use this wisely. # # Notice option "include" won't be rewritten by command "CONFIG REWRITE" # from admin or Redis Sentinel. Since Redis always uses the last processed # line as value of a configuration directive, you'd better put includes # at the beginning of this file to avoid overwriting config change at runtime. # # If instead you are interested in using includes to override configuration # options, it is better to use include as the last line. # # 假如說你有一個可用於所有的 redis server 的標準配置模板, # 但針對某些 server 又需要一些個性化的設置, # 你可以使用 include 來包含一些其他的配置文件,這對你來說是非常有用的。 # # 但是要註意哦,include 是不能被 config rewrite 命令改寫的 # 由於 redis 總是以最後的加工線作為一個配置指令值,所以你最好是把 include 放在這個文件的最前面, # 以避免在運行時覆蓋配置的改變,相反,你就把它放在後面 # include /path/to/local.conf # include /path/to/other.conf ################################ GENERAL ##################################### ################################ 常用 ##################################### # 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. # 預設情況下 redis 不是作為守護進程運行的,如果你想讓它在後臺運行,你就把它改成 yes。 # 當redis作為守護進程運行的時候,它會寫一個 pid 到 /var/run/redis.pid 文件裡面。 daemonize yes # When running daemonized, Redis writes a pid file in /var/run/redis.pid by # default. You can specify a custom pid file location here. # 當 Redis 以守護進程的方式運行的時候,Redis 預設會把 pid 文件放在/var/run/redis.pid # 可配置到其他地址,當運行多個 redis 服務時,需要指定不同的 pid 文件和埠 # 指定存儲Redis進程號的文件路徑 pidfile /var/run/redis.pid # Accept connections on the specified port, default is 6379. # If port 0 is specified Redis will not listen on a TCP socket. # 埠,預設埠是6379,生產環境中建議更改埠號,安全性更高 # 如果你設為 0 ,redis 將不在 socket 上監聽任何客戶端連接。 port 9966 # TCP listen() backlog. # # In high requests-per-second environments you need an high backlog in order # to avoid slow clients connections issues. Note that the Linux kernel # will silently truncate it to the value of /proc/sys/net/core/somaxconn so # make sure to raise both the value of somaxconn and tcp_max_syn_backlog # in order to get the desired effect. # TCP 監聽的最大容納數量 # 此參數確定了TCP連接中已完成隊列(完成三次握手之後)的長度, # 當系統併發量大並且客戶端速度緩慢的時候,你需要把這個值調高以避免客戶端連接緩慢的問題。 # Linux 內核會一聲不響的把這個值縮小成 /proc/sys/net/core/somaxconn 對應的值,預設是511,而Linux的預設參數值是128。 # 所以可以將這二個參數一起參考設定,你以便達到你的預期。 # tcp-backlog 511 # By default Redis listens for connections from all the network interfaces # available on the server. It is possible to listen to just one or multiple # interfaces using the "bind" configuration directive, followed by one or # more IP addresses. # # Examples: # # bind 192.168.1.100 10.0.0.1 # 有時候為了安全起見,redis一般都是監聽127.0.0.1 但是有時候又有同網段能連接的需求,當然可以綁定0.0.0.0 用iptables來控制訪問許可權,或者設置redis訪問密碼來保證數據安全 # 不設置將處理所有請求,建議生產環境中設置,有個誤區:bind是用來限制外網IP訪問的,其實不是,限制外網ip訪問可以通過iptables;如:-A INPUT -s 10.10.1.0/24 -p tcp -m state --state NEW -m tcp --dport 9966 -j ACCEPT ; # 實際上,bind ip 綁定的是redis所在伺服器網卡的ip,當然127.0.0.1也是可以的 #如果綁定一個外網ip,就會報錯:Creating Server TCP listening socket xxx.xxx.xxx.xxx:9966: bind: Cannot assign requested address # bind 127.0.0.1 bind 127.0.0.1 10.10.1.3 # 假設綁定是以上ip,使用 netstat -anp|grep 9966 會發現,這兩個ip被bind,其中10.10.1.3是伺服器網卡的ip # tcp 0 0 10.10.1.3:9966 0.0.0.0:* LISTEN 11188/redis-server # tcp 0 0 127.0.0.1:9966 0.0.0.0:* LISTEN 11188/redis-server # Specify the path for the Unix socket that will be used to listen for # incoming connections. There is no default, so Redis will not listen # on a unix socket when not specified. # # unixsocket /tmp/redis.sock # unixsocketperm 700 # Close the connection after a client is idle for N seconds (0 to disable) # 客戶端和Redis服務端的連接超時時間,預設是0,表示永不超時。 timeout 0 # TCP keepalive. # # If non-zero, use SO_KEEPALIVE to send TCP ACKs to clients in absence # of communication. This is useful for two reasons: # # 1) Detect dead peers. # 2) Take the connection alive from the point of view of network # equipment in the middle. # # On Linux, the specified value (in seconds) is the period used to send ACKs. # Note that to close the connection the double of the time is needed. # On other kernels the period depends on the kernel configuration. # # A reasonable value for this option is 60 seconds. # tcp 心跳包。 # # 如果設置為非零,則在與客戶端缺乏通訊的時候使用 SO_KEEPALIVE 發送 tcp acks 給客戶端。 # 這個之所有有用,主要由兩個原因: # # 1) 防止死的 peers # 2) Take the connection alive from the point of view of network # equipment in the middle. # # 推薦一個合理的值就是60秒 tcp-keepalive 0 # 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) # 日誌記錄等級,4個可選值debug,verbose,notice,warning # 可以是下麵的這些值: # debug (適用於開發或測試階段) # verbose (many rarely useful info, but not a mess like the debug level) # notice (適用於生產環境) # warning (僅僅一些重要的消息被記錄) 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 #配置 log 文件地址,預設列印在命令行終端的視窗上,也可設為/dev/null屏蔽日誌、 logfile "/data/logs/redis/redis.log" # To enable logging to the system logger, just set 'syslog-enabled' to yes, # and optionally update the other syslog parameters to suit your needs. # 要想把日誌記錄到系統日誌,就把它改成 yes, # 也可以可選擇性的更新其他的syslog 參數以達到你的要求 # syslog-enabled no # Specify the syslog identity. # 設置 syslog 的 identity。 # syslog-ident redis # Specify the syslog facility. Must be USER or between LOCAL0-LOCAL7. # syslog-facility local0 # Set the number of databases. The default database is DB 0, you can select # a different one on a per-connection basis using SELECT <dbid> where # dbid is a number between 0 and 'databases'-1 # 可用的資料庫數,預設值為16,預設資料庫為0,資料庫範圍在0-(database-1)之間 databases 16 ################################ SNAPSHOTTING ################################ ################################ 快照 ################################ # # 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 "" # 在 900 秒內最少有 1 個 key 被改動,或者 300 秒內最少有 10 個 key 被改動,又或者 60 秒內最少有 1000 個 key 被改動,以上三個條件隨便滿足一個,就觸發一次保存操作。 # if(在60秒之內有10000個keys發生變化時){ # 進行鏡像備份 # }else if(在300秒之內有10個keys發生了變化){ # 進行鏡像備份 # }else if(在900秒之內有1個keys發生了變化){ # 進行鏡像備份 # } 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. # 預設情況下,如果 redis 最後一次的後臺保存失敗,redis 將停止接受寫操作, # 這樣以一種強硬的方式讓用戶知道數據不能正確的持久化到磁碟, # 否則就會沒人註意到災難的發生。 # # 如果後臺保存進程重新啟動工作了,redis 也將自動的允許寫操作。 # # 然而你要是安裝了靠譜的監控,你可能不希望 redis 這樣做,那你就改成 no 好 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. # 在進行備份時,是否進行壓縮 # 是否在 dump .rdb 資料庫的時候使用 LZF 壓縮字元串 # 預設都設為 yes # 如果你希望保存子進程節省點 cpu ,你就設置它為 no , # 不過這個數據集可能就會比較大 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. # 讀取和寫入的時候是否支持CRC64校驗,預設是開啟的 rdbchecksum yes # The filename where to dump the DB # 備份文件的文件名 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. # 資料庫備份的文件放置的路徑 # 路徑跟文件名分開配置是因為 Redis 備份時,先會將當前資料庫的狀態寫入到一個臨時文件 # 等備份完成時,再把該臨時文件替換為上面所指定的文件 # 而臨時文件和上面所配置的備份文件都會放在這個指定的路徑當中 # 預設值為 ./ dir /data/data/redis/ ################################# REPLICATION ################################# ################################# 主從複製 ################################# # Master-Slave replication. Use slaveof to make a Redis instance a copy of # another Redis server. A few things to understand ASAP about Redis replication. # # 1) Redis replication is asynchronous, but you can configure a master to # stop accepting writes if it appears to be not connected with at least # a given number of slaves. # 2) Redis slaves are able to perform a partial resynchronization with the # master if the replication link is lost for a relatively small amount of # time. You may want to configure the replication backlog size (see the next # sections of this file) with a sensible value depending on your needs. # 3) Replication is automatic and does not need user intervention. After a # network partition slaves automatically try to reconnect to masters # and resynchronize with them. # # 設置該資料庫為其他資料庫的從資料庫 # slaveof <masterip> <masterport> 當本機為從服務時,設置主服務的IP及埠 # slaveof <masterip> <masterport> # If the master is password protected (using the "requirepass" configuration # directive below) it is possible to tell the slave to authenticate before # starting the replication synchronization process, otherwise the master will # refuse the slave request. # # 指定與主資料庫連接時需要的密碼驗證 # masterauth <master-password> 當本機為從服務時,設置訪問master伺服器的密碼 # masterauth <master-password> # When a slave loses its connection with the master, or when the replication # is still in progress, the slave can act in two different ways: # # 1) if slave-serve-stale-data is set to 'yes' (the default) the slave will # still reply to client requests, possibly with out of date data, or the # data set may just be empty if this is the first synchronization. # # 2) if slave-serve-stale-data is set to 'no' the slave will reply with # an error "SYNC with master in progress" to all the kind of commands # but to INFO and SLAVEOF. # # 當slave伺服器和master伺服器失去連接後,或者當數據正在複製傳輸的時候,如果此參數值設置“yes”,slave伺服器可以繼續接受客戶端的請求,否則,會返回給請求的客戶端如下信息“SYNC with master in progress”,除了INFO,SLAVEOF這兩個命令 slave-serve-stale-data yes # You can configure a slave instance to accept writes or not. Writing against # a slave instance may be useful to store some ephemeral data (because data # written on a slave will be easily deleted after resync with the master) but # may also cause problems if clients are writing to it because of a # misconfiguration. # # Since Redis 2.6 by default slaves are read-only. # # Note: read only slaves are not designed to be exposed to untrusted clients # on the internet. It's just a protection layer against misuse of the instance. # Still a read only slave exports by default all the administrative commands # such as CONFIG, DEBUG, and so forth. To a limited extent you can improve # security of read only slaves using 'rename-command' to shadow all the # administrative / dangerous commands. # 是否允許slave伺服器節點只提供讀服務 slave-read-only yes # Replication SYNC strategy: disk or socket. # # ------------------------------------------------------- # WARNING: DISKLESS REPLICATION IS EXPERIMENTAL CURRENTLY # ------------------------------------------------------- # # New slaves and reconnecting slaves that are not able to continue the replication # process just receiving differences, need to do what is called a "full # synchronization". An RDB file is transmitted from the master to the slaves. # The transmission can happen in two different ways: # # 1) Disk-backed: The Redis master creates a new process that writes the RDB # file on disk. Later the file is transferred by the parent # process to the slaves incrementally. # 2) Diskless: The Redis master creates a new process that directly writes the # RDB file to slave sockets, without touching the disk at all. # # With disk-backed replication, while the RDB file is generated, more slaves # can be queued and served with the RDB file as soon as the current child producing # the RDB file finishes its work. With diskless replication instead once # the transfer starts, new slaves arriving will be queued and a new transfer # will start when the current one terminates. # # When diskless replication is used, the master waits a configurable amount of # time (in seconds) before starting the transfer in the hope that multiple slaves # will arrive and the transfer can be parallelized. # # With slow disks and fast (large bandwidth) networks, diskless replication # works better. repl-diskless-sync no # When diskless replication is enabled, it is possible to configure the delay # the server waits in order to spawn the child that transfers the RDB via socket # to the slaves. # # This is important since once the transfer starts, it is not possible to serve # new slaves arriving, that will be queued for the next RDB transfer, so the server # waits a delay in order to let more slaves arrive. # # The delay is specified in seconds, and by default is 5 seconds. To disable # it entirely just set it to 0 seconds and the transfer will start ASAP. repl-diskless-sync-delay 5 # Slaves send PINGs to server in a predefined interval. It's possible to change # this interval with the repl_ping_slave_period option. The default value is 10 # seconds. # # Slaves 在一個預定義的時間間隔內發送 ping 命令到 server 。 # 你可以改變這個時間間隔。預設為 10 秒。 # repl-ping-slave-period 10 # The following option sets the replication timeout for: # # 1) Bulk transfer I/O during SYNC, from the point of view of slave. # 2) Master timeout from the point of view of slaves (data, pings). # 3) Slave timeout from the point of view of masters (REPLCONF ACK pings). # # It is important to make sure that this value is greater than the value # specified for repl-ping-slave-period otherwise a timeout will be detected # every time there is low traffic between the master and the slave. # # 設置主從複製過期時間 # 這個值一定要比 repl-ping-slave-period 大 # repl-timeout 60 # Disable TCP_NODELAY on the slave socket after SYNC? # # If you select "yes" Redis will use a smaller number of TCP packets and # less bandwidth to send data to slaves. But this can add a delay for # the data to appear on the slave side, up to 40 milliseconds with # Linux kernels using a default configuration. # # If you select "no" the delay for data to appear on the slave side will # be reduced but more bandwidth will be used for replication. # # By default we optimize for low latency, but in very high traffic conditions # or when the master and slaves are many hops away, turning this to "yes" may # be a good idea. # 指定向slave同步數據時,是否禁用socket的NO_DELAY選 項。若配置為“yes”,則禁用NO_DELAY,則TCP協議棧會合併小包統一發送,這樣可以減少主從節點間的包數量並節省帶寬,但會增加數據同步到 slave的時間。若配置為“no”,表明啟用NO_DELAY,則TCP協議棧不會延遲小包的發送時機,這樣數據同步的延時會減少,但需要更大的帶寬。 通常情況下,應該配置為no以降低同步延時,但在主從節點間網路負載已經很高的情況下,可以配置為yes。 repl-disable-tcp-nodelay no # Set the replication backlog size. The backlog is a buffer that accumulates # slave data when slaves are disconnected for some time, so that when a slave # wants to reconnect again, often a full resync is not needed, but a partial # resync is enough, just passing the portion of data the slave missed while # disconnected. # # The bigger the replication backlog, the longer the time the slave can be # disconnected and later be able to perform a partial resynchronization. # # The backlog is only allocated once there is at least a slave connected. # # 設置主從複製容量大小。這個 backlog 是一個用來在 slaves 被斷開連接時 # 存放 slave 數據的 buffer,所以當一個 slave 想要重新連接,通常不希望全部重新同步, # 只是部分同步就夠了,僅僅傳遞 slave 在斷開連接時丟失的這部分數據。 # # The biggest the replication backlog, the longer the time the slave can be # disconnected and later be able to perform a partial resynchronization. # 這個值越大,salve 可以斷開連接的時間就越長。 # repl-backlog-size 1mb # After a master has no longer connected slaves for some time, the backlog # will be freed. The following option configures the amount of seconds that # need to elapse, starting from the time the last slave disconnected, for # the backlog buffer to be freed. # # A value of 0 means to never release the backlog. # # 在某些時候,master 不再連接 slaves,backlog 將被釋放。 # 如果設置為 0 ,意味著絕不釋放 backlog 。 # repl-backlog-ttl 3600 # The slave priority is an integer number published by Redis in the INFO output. # It is used by Redis Sentinel in order to select a slave to promote into a # master if the master is no longer working correctly. # # A slave with a low priority number is considered better for promotion, so # for instance if there are three slaves with priority 10, 100, 25 Sentinel will # pick the one with priority 10, that is the lowest. # # However a special priority of 0 marks the slave as not able to perform the # role of master, so a slave with priority of 0 will never be selected by # Redis Sentinel for promotion. # # By default the priority is 100. # 指定slave的優先順序。在不只1個slave存在的部署環境下,當master宕機時,Redis # Sentinel會將priority值最小的slave提升為master。 # 這個值越小,就越會被優先選中,需要註意的是, # 若該配置項為0,則對應的slave永遠不會自動提升為master。 slave-priority 100 # It is possible for a master to stop accepting writes if there are less than # N slaves connected, having a lag less or equal than M seconds. # # The N slaves need to be in "online" state. # # The lag in seconds, that must be <= the specified value, is calculated from # the last ping received from the slave, that is usually sent every second. # # This option does not GUARANTEE that N replicas will accept the write, but # will limit the window of exposure for lost writes in case not enough slaves # are available, to the specified number of seconds # # For example to require at least 3 slaves with a lag <= 10 seconds use: # # min-slaves-to-write 3 # min-slaves-max-lag 10 # # Setting one or the other to 0 disables the feature. # # By default min-slaves-to-write is set to 0 (feature disabled) and # min-slaves-max-lag is set to 10. ################################## SECURITY ################################### ################################## 安全 ################################### # 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. # # 設置連接redis的密碼 # redis速度相當快,一個外部用戶在一秒鐘進行150K次密碼嘗試,需指定強大的密碼來防止暴力破解 requirepass set_enough_strong_passwd # Command renaming. # # It is possible to change the name of dangerous commands in a shared # environment. For instance the CONFIG command may be renamed into something # hard to guess so that it will still be available for internal-use tools # but not available for general clients. # # Example: # # rename-command CONFIG b840fc02d524045429941cc15f59e41cb7be6c52 # # It is also possible to completely kill a command by renaming it into # an empty string: # # rename-command CONFIG "" # # Please note that changing the name of commands that are logged into the # AOF file or transmitted to slaves may cause problems. # 重命名一些高危命令,用來禁止高危命令 rename-command FLUSHALL ZYzv6FOBdwflW2nX rename-command CONFIG aI7zwm1GDzMMrEi rename-command EVAL S9UHPKEpSvUJMM rename-command FLUSHDB D60FPVDJuip7gy6l ################################### LIMITS #################################### ################################### 限制 #################################### # Set the max number of connected clients at the same time. By default # this limit is set to 10000 clients, however if the Redis server is not # able to configure the process file limit to allow for the specified limit # the max number of allowed clients is set to the current file limit # minus 32 (as Redis reserves a few file descriptors for internal uses). # # Once the limit is reached Redis will close all the new connections sending # an error 'max number of clients reached'. # # 限制同時連接的客戶數量,預設是10000 # 當連接數超過這個值時,redis 將不再接收其他連接請求,客戶端嘗試連接時將收到 error 信息 # maxclients 10000 # Don't use more memory than the specified amount of bytes. # When the memory limit is reached Redis will try to remove keys # according to the eviction policy selected (see maxmemory-policy). # # If Redis can't remove keys according to the policy, or if the policy is # set to 'noeviction', Redis will start to reply with errors to commands # that would use more memory, like SET, LPUSH, and so on, and will continue # to reply to read-only commands like GET. # # This option is usually useful when using Redis as an LRU cache, or to set # a hard memory limit for an instance (using the 'noeviction' policy). # # WARNING: If you have slaves attached to an instance with maxmemory on, # the size of the output buffers needed to feed the slaves are subtracted # from the used memory count, so that network problems / resyncs will # not trigger a loop where keys are evicted, and in turn the output # buffer of slaves is full with DELs of keys evicted triggering the deletion # of more keys, and so forth until the database is completely emptied. # # In short... if you have slaves attached it is suggested that you set a lower # limit for maxmemory so that there is some free RAM on the system for slave # output buffers (but this is not needed if the policy is 'noeviction'). # # 設置redis能夠使用的最大記憶體。 # 達到最大記憶體設置後,Redis會先嘗試清除已到期或即將到期的Key(設置過expire信息的key) # 在刪除時,按照過期時間進行刪除,最早將要被過期的key將最先被刪除 # 如果已到期或即將到期的key刪光,仍進行set操作,那麼將返回錯誤 # 此時redis將不再接收寫請求,只接收get請求。 # maxmemory的設置比較適合於把redis當作於類似memcached 的緩存來使用 # maxmemory <bytes> # MAXMEMORY POLICY: how Redis will select what to remove when maxmemory # is reached. You can select among five behaviors: # # volatile-lru -> remove the key with an expire set using an LRU algorithm # allkeys-lru -> remove any key according to the LRU algorithm # volatile-random -> remove a random key with an expire set # allkeys-random -> remove a random key, any key # volatile-ttl -> remove the key with the nearest expire time (minor TTL) # noeviction -> don't expire at all, just return an error on write operations # # Note: with any of the above policies, Redis will return an error on write # operations, when there are no suitable keys for eviction. # # At the date of writing these commands are: set setnx setex append # incr decr rpush lpush rpushx lpushx linsert lset rpoplpush sadd # sinter sinterstore sunion sunionstore sdiff sdiffstore zadd zincrby # zunionstore zinterstore hset hsetnx hmset hincrby incrby decrby # getset mset msetnx exec sort # # The default is: # # maxmemory-policy noeviction # LRU and minimal TTL algorithms are not precise algorithms but approximated # algorithms (in order to save memory), so you can tune it for speed or # accuracy. For default Redis will check five keys and pick the one that was # used less recently, you can change the sample size using the following # configuration directive. # # The default of 5 produces good enough results. 10 Approximates very closely # true LRU but costs a bit more CPU. 3 is very fast but not very accurate. # # maxmemory-samples 5 ############################## APPEND ONLY MODE ############################### # By default Redis asynchronously dumps the dataset on disk. This mode is # good enough in many applications, but an issue with the Redis process or # a power outage may result into a few minutes of writes lost (depending on # the configured save points). # # The Append Only File is an alternative persistence mode that provides # much better durability. For instance using the default data fsync policy # (see later in the config file) Redis can lose just one second of writes in a # dramatic event like a server power outage, or a single write if something # wrong with the Redis process itself happens, but the operating system is # still running correctly. # # AOF and RDB persistence can be enabled at the same time without problems. # If the AOF is enabled on startup Redis will load the AOF, that is the file # with the better durability guarantees. # # Please check http://redis.io/topics/persistence for more information. # redis 預設每次更新操作後會在後臺非同步的把資料庫鏡像備份到磁碟,但該備份非常耗時,且備份不宜太頻繁 # redis 同步數據文件是按上面save條件來同步的 # 如果發生諸如拉閘限電、拔插頭等狀況,那麼將造成比較大範圍的數據丟失 # 所以redis提供了另外一種更加高效的資料庫備份及災難恢復方式 # 開啟append only 模式後,redis 將每一次寫操作請求都追加到appendonly.aof 文件中 # redis重新啟動時,會從該文件恢復出之前的狀態。 # 但可能會造成 appendonly.aof 文件過大,所以redis支持BGREWRITEAOF 指令,對appendonly.aof重新整理,預設是不開啟的。 appendonly no # The name of the append only file (default: "appendonly.aof") # 預設為appendonly.aof。 appendfilename "appendonly.aof" # The fsync() call tells the Operating System to actually write data on disk # instead of waiting for more data in the output buffer. Some OS will really flush # data on disk, some other OS will just try to do it ASAP. # # Redis supports three different modes: # # no: don't fsync, just let the OS flush the data when it wants. Faster. # always: fsync after every write to the append only log. Slow, Safest. # everysec: fsync only one time every second. Compromise. # # The default is "everysec", as that's usually the right compromise between # speed and data safety. It's up to you to understand if you can relax this to # "no" that will let the operating system flush the output buffer when # it wants, for better performances (but if you can live with the idea of # some data loss consider the default persistence mode that's snapshotting), # or on the contrary, use "always" that's very slow but a bit safer than # everysec. # # More details please check the following article: # http://antirez.com/post/redis-persistence-demystified.html # # If unsure, use "everysec". # 設置對 appendonly.aof 文件進行同步的頻率,有三種選擇always、everysec、no,預設是everysec表示每秒同步一次。 # always 表示每次有寫操作都進行同步,everysec 表示對寫操作進行累積,每秒同步一次。 # no表示等操作系統進行數據緩存同步到磁碟,都進行同步,everysec 表示對寫操作進行累積,每秒同步一次 # appendfsync always # appendfsync everysec # appendfsync no # When the AOF fsync policy is set to always or everysec, and a background # saving process (a background save or AOF log background rewriting) is # performing a lot of I/O against the disk, in some Linux configurations # Redis may block too long on the fsync() call. Note that there is no fix for # this currently, as even performing fsync in a different thread will block # our synchronous write(2) call. # # In order to mitigate this problem it's possible to use the following option # that will prevent fsync() from being called in the main process while a # BGSAVE or BGREWRITEAOF is in progress. # # This means that while another child is saving, the durability of Redis is # the same as "appendfsync none". In practical terms, this means that it is # possible to lose up to 30 seconds of log in the worst scenario (with the # default Linux settings). # # If you have latency problems turn this to "yes". Otherwise leave it as # "no" that is the safest pick from the point of view of durability. # 指定是否在後臺aof文件rewrite期間調用fsync,預設為no,表示要調用fsync(無論後臺是否有子進程在刷盤)。Redis在後臺寫RDB文件或重寫afo文件期間會存在大量磁碟IO,此時,在某些linux系統中,調用fsync可能會阻塞。 no-appendfsync-on-rewrite yes # Automatic rewrite of the append only file. # Redis is able to automatically rewrite the log file implicitly calling # BGREWRITEAOF when the AOF log size grows by the specified percentage. # # This is how it works: Redis remembers the size of the AOF file after the # latest rewrite (if no rewrite has happened since the restart, the size of # the AOF at startup is used). # # This base size is compared to the current size. If the current size is # bigger than the specified percentage, the rewrite is triggered. Also # you need to specify a minimal size for the AOF file to be rewritten, this # is useful to avoid rewriting the AOF file even if the percentage increase # is reached but it is still pretty small. # # Specify a percentage of zero in order to disable the automatic AOF # rewrite feature. # 指定Redis重寫aof文件的條件,預設為100,表示與上次rewrite的aof文件大小相比,當前aof文件增長量超過上次afo文件大小的100%時,就會觸發background rewrite。若配置為0,則會禁用自動rewrite auto-aof-rewrite-percentage 100 # 指定觸發rewrite的aof文件大小。若aof文件小於該值,即使當前文件的增量比例達到auto-aof-rewrite-percentage的配置值,也不會觸發自動rewrite。即這兩個配置項同時滿足時,才會觸發rewrite。 auto-aof-rewrite-min-size 64mb # An AOF file may be found to be truncated at the end during the Redis # startup process, when the AOF data gets loaded back into memory. # This may happen when the system where Redis is running # crashes, especially when an ext4 filesystem is mounted without the # data=ordered option (however this can't happen when Redis itself # crashes or aborts but the operating system still works correctly). # # Redis can either exit with an error when this happens, or load as much # data as possible (the default now) and start if the AOF file is found # to be truncated at the end. The following option controls this behavior. # # If aof-load-truncated is set to yes, a truncated AOF file is loaded and # the Redis server starts emitting a log to inform the user of the event. # Otherwise if the option is set to no, the server aborts with an error # and refuses to start. When the option is set to no, the user requires # to fix the AOF file using the "redis-check-aof" utility before to restart # the server. # # Note that if the AOF file will be found to be corrupted in the middle # the server will still exit with an error. This option only applies when # Redis will try to read more data from the AOF file but not enough bytes # will be found. aof-load-truncated yes ################################ LUA SCRIPTING ############################### # Max execution time of a Lua script in milliseconds. # # If the maximum execution time is reached Redis will log that a script is # still in execution after the maximum allowed time and will start to # reply to queries with an error. # # When a long running script exceeds the maximum execution time only the # SCRIPT KILL and SHUTDOWN NOSAVE commands are available. The first can be # used to stop a script that did not yet called write commands. The second # is the only way to shut down the server in the case a write command was # already issued by the script but the user doesn't want to wait for the natural # termination of the script. # # Set it to 0 or a negative value for unlimited execution without warnings. # 一個Lua腳本最長的執行時間,單位為毫秒,如果為0或負數表示無限執行時間,預設為5000 lua-time-limit 5000 ################################ REDIS CLUSTER ############################### # # ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ # WARNING EXPERIMENTAL: Redis Cluster is considered to be stable code, however # in order to mark it as "mature" we need to wait for a non trivial percentage # of users to deploy it in production. # ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ # # Normal Redis instances can't be part of a Redis Cluster; only nodes that are # started as cluster nodes can. In order to start a Redis instance as a # cluster node enable the cluster support uncommenting the following: # # cluster-enabled yes # Every cluster node has a cluster configuration file. This file is not # intended to be edited by hand. It is created and updated by Redis nodes. # Every Redis Cluster node requires a different cluster configuration file. # Make sure that instances running in the same system do not have # overlapping cluster configuration file names. # # cluster-config-file nodes-6379.conf # Cluster node timeout is the amount of milliseconds a node must be unreachable # for it to be considered in failure state. # Most other internal time limits are multiple of the node timeout. # # cluster-node-timeout 15000 # A slave of a failing master will avoid to start a failover if its data # looks too old. # # There is no simple way for a slave to actually have a exact measure of # its "data age", so the following two checks are performed: # # 1) If there are multiple slaves able to failover, they exchange messages # in order to try to give an advantage to the slave with the best # replication offset (more data from the master processed). # Slaves will try to get their rank by offset, and apply to the start # of the failover a delay proportional to their rank. # # 2) Every single slave computes the time of the last interaction with # its master. This can be the last ping or command received (if the master # is still in the "connected" state), or the time that elapsed since the # disconnection with the master (if the replication link is currently down). # If the last interaction is too old, the slave will not try to failover # at all. # # The point "2" can be tuned by user. Specifically a slave will not perform # the failover if, since the last interaction with the master, the time # elapsed is greater than: # # (node-timeout * slave-validity-factor) + repl-ping-slave-period # # So for example if node-timeout is 30 seconds, and the slave-validity-factor # is 10, and assuming a default repl-ping-slave-period of 10 seconds, the # slave will not try to failover if it was not able to talk with the master # for longer than 310 seconds. # # A large slave-validity-factor may allow slaves with too old data to failover # a master, while a too small value may prevent the cluster from being able to # elect a slave at all. # # For maximum availability, it is possible to set the slave-validity-factor # to a value of 0, which means, that slaves will always try to failover the # master regardless of the last time they interacted with the master. # (However they'll always try to apply a delay proportional to their # offset rank). # # Zero is the only value able to guarantee that when all the partitions heal # the cluster will always be able to continue. # # cluster-slave-validity-factor 10 # Cluster slaves are able to migrate to orphaned masters, that are masters # that are left without working slaves. This improves the cluster ability # to resist to failures as otherwise an orphaned master can't be failed over # in case of failure if it has no working slaves. # # Slaves migrate to orphaned masters only if there are still at least a # given number of other working slaves for their old master. This number # is the "migration barrier". A migration barrier of 1 means that a slave # will migrate only if there is at least 1 other working slave for its master # and so forth. It usually reflects the number of slaves you want for every # master in your cluster. # # Default is 1 (slaves migrate only if their masters remain with at least # one slave). To disable migration just set it to a very large value. # A value of 0 can be set but is useful only for debugging and dangerous # in production. # # cluster-migration-barrier 1 # By default Redis Cluster nodes stop accepting queries if they detect there # is at least an hash slot uncovered (no available node is serving it). # This way if the cluster is partially down (for example a range of hash slots # are no longer covered) all the cluster becomes, eventually, unavailable. # It automatically returns available as soon as all the slots are covered again. # # However sometimes you want the subset of the cluster which is working, # to continue to accept queries for the part of the key space that is still # covered. In order to do so, just set the cluster-require-full-coverage # option to no. # # cluster-require-full-coverage yes # In order to setup your cluster make sure to read the documentation # available at http://redis.io web site. ################################## SLOW LOG ################################### # The Redis Slow Log is a system to log queries that exceeded a specified # execution time. The execution time does not include the I/O operations # like talking with the client, sending the reply and so forth, # but just the time needed to actually execute the command (this is the only # stage of command execution where the thread is blocked and can not serve # other requests in the meantime). # # You can configure the slow log with two parameters: one tells Redis # what is the execution time, in microseconds, to exceed in order for the # command to get logged, and the other parameter is the length of the # slow log. When a new command is logged the oldest one is removed from the # queue of logged commands. # The following time is expressed in microseconds, so 1000000 is equivalent # to one second. Note that a negative number disables the slow log, while # a value of zero forces the logging of every command. slowlog-log-slower-than 10000 # There is no limit to this length. Just be aware that it will consume memory. # You can reclaim memory used by the slow log with SLOWLOG RESET. slowlog-max-len 128 ################################ LATENCY MONITOR ############################## # The Redis latency monitoring subsystem samples different operations # at runtime in order to collect data related to possible sources of # latency of a Redis instance. # # Via the LATENCY command this information is available to the user that can # print graphs and obtain reports. # # The system only logs operations that were performed in a time equal or # greater than the amount of milliseconds specified via the # latency-monitor-threshold configuration directive. When its value is set # to zero, the latency monitor is turned off. # # By default latency monitoring is disabled since it is mostly not needed # if you don't have latency issues, and collecting data has a performance # impact, that while very small, can be measured under big load. Latency # monitoring can easily be enabled at runtime using the command # "CONFIG SET latency-monitor-threshold <milliseconds>" if needed. latency-monitor-threshold 0 ############################# EVENT NOTIFICATION ############################## # Redis can notify Pub/Sub clients about events happening in the key space. # This feature is documented at http://redis.io/topics/notifications # # For instance if keyspace events notification is enabled, and a client # performs a DEL operation on key "foo" stored in the Database 0, two # messages will be published via Pub/Sub: # # PUBLISH __keyspace@0__:foo del # PUBLISH __keyevent@0__:del foo # # It is possible to select the events that Redis will notify among a set # of classes. Every class is identified by a single character: # # K Keyspace events, published with __keyspace@<db>__ prefix. # E Keyevent events, published with __keyevent@<db>__ prefix. # g Generic commands (non-type specific) like DEL, EXPIRE, RENAME, ... # $ String commands # l List commands # s Set commands # h Hash commands # z Sorted set commands # x Expired events (events generated every time a key expires) # e Evicted events (events generated when a key is evicted for maxmemory) # A Alias for g$lshzxe, so that the "AKE" string means all the events. # # The "notify-keyspace-events" takes as argument a string that is composed # of zero or multiple characters. The empty string means that notifications # are disabled. # # Example: to enable list and generic events, from the point of view of the # event name, use: # # notify-keyspace-events Elg # # Example 2: to get the stream of the expired keys subscribing to channel # name __keyevent@0__:expired use: # # notify-keyspace-events Ex # # By default all notifications are disabled because most users don't need # this feature and the feature has some overhead. Note that if you don't # specify at least one of K or E, no events will be delivered. notify-keyspace-events "" ############################### ADVANCED CONFIG ############################### # Hashes are encoded using a memory efficient data structure when they have a # small number of entries, and the biggest entry does not exceed a given # threshold. These thresholds can be configured using the following directives. # 當hash中包含超過指定元素個數並且最大的元素沒有超過臨界時, # hash將以一種特殊的編碼方式(大大減少記憶體使用)來存儲,這裡可以設置這兩個臨界值 hash-max-ziplist-entries 512 hash-max-ziplist-value 64 # Similarly to hashes, small lists are also encoded in a special way in order # to save a lot of space. The special representation is only used when # you are under the following limits: # list數據類型多少節點以下會採用去指針的緊湊存儲格式。 # list數據類型節點值大小小於多少位元組會採用緊湊存儲格式。 list-max-ziplist-entries 512 list-max-ziplist-value 64 # Sets have a special encoding in just one case: when a set is composed # of just strings that happen to be integers in radix 10 in the range # of 64 bit signed integers. # The following configuration setting sets the limit in the size of the # set in order to use this special memory saving encoding. # set數據類型內部數據如果全部是數值型,且包含多少節點以下會採用緊湊格式存儲。 set-max-intset-entries 512 # Similarly to hashes and lists, sorted sets are also specially encoded in # order to save a lot of space. This encoding is only used when the length and # elements of a sorted set are below the following limits: # zsort數據類型多少節點以下會採用去指針的緊湊存儲格式。 # zsort數據類型節點值大小小於多少位元組會採用緊湊存儲格式。 zset-max-ziplist-entries 128 zset-max-ziplist-value 64 # HyperLogLog sparse representation bytes limit. The limit includes the # 16 bytes header. When an HyperLogLog using the sparse representation crosses # this limit, it is converted into the dense representation. # # A value greater than 16000 is totally useless, since at that point the # dense representation is more memory efficient. # # The suggested value is ~ 3000 in order to have the benefits of # the space efficient encoding without slowing down too much PFADD, # which is O(N) with the sparse encoding. The value can be raised to # ~ 10000 when CPU is not a concern, but space is, and the data set is # composed of many HyperLogLogs with cardinality in the 0 - 15000 range. hll-sparse-max-bytes 3000 # Active rehashing uses 1 millisecond every 100 milliseconds of CPU time in # order to help rehashing the main Redis hash table (the one mapping top-level # keys to values). The hash table implementation Redis uses (see dict.c) # performs a lazy rehashing: the more operation you run into a hash table # that is rehashing, the more rehashing "steps" are performed, so if the # server is idle the rehashing is never complete and some more memory is used # by the hash table. # # The default is to use this millisecond 10 times every second in order to # actively rehash the main dictionaries, freeing memory when possible. # # If unsure: # use "activerehashing no" if you have hard latency requirements and it is # not a good thing in your environment that Redis can reply from time to time # to queries with 2 milliseconds delay. # # use "activerehashing yes" if you don't have such hard requirements but # want to free memory asap when possible. # Redis將在每100毫秒時使用1毫秒的CPU時間來對redis的hash表進行重新hash,可以降低記憶體的使用 # 當你的使用場景中,有非常嚴格的實時性需要,不能夠接受Redis時不時的對請求有2毫秒的延遲的話,把這項配置為no。 # 如果沒有這麼嚴格的實時性要求,可以設置為yes,以便能夠儘可能快的釋放記憶體 activerehashing yes # The client output buffer limits can be used to force disconnection of clients # that are not reading data from the server fast enough for some reason (a # common reason is that a Pub/Sub client can't consume messages as fast as the # publisher can produce them). # # The limit can be set differently for the three different classes of clients: # # normal -> normal clients including MONITOR clients # slave -> slave clients # pubsub -> clients subscribed to at least one pubsub channel or pattern # # The syntax of every client-output-buffer-limit directive is the following: # # client-output-buffer-limit <class> <hard limit> <soft limit> <soft seconds> # # A client is immediately disconnected once the hard limit is reached, or if # the soft limit is reached and remains reached for the specified number of # seconds (continuously). # So for instance if the hard limit is 32 megabytes and the soft limit is # 16 megabytes / 10 seconds, the client will get disconnected immediately # if the size of the output buffers reach 32 megabytes, but will also get # disconnected if the client reaches 16 megabytes and continuously overcomes # the limit for 10 seconds. # # By default normal clients are not limited because they don't receive data # without asking (in a push way), but just after a request, so only # asynchronous clients may create a scenario where data is requested faster # than it can read. # # Instead there is a default limit for pubsub and slave clients, since # subscribers and slaves receive data in a push fashion. # # Both the hard or the soft limit can be disabled by setting them to zero. client-output-buffer-limit normal 0 0 0 client-output-buffer-limit slave 256mb 64mb 60 client-output-buffer-limit pubsub 32mb 8mb 60 # Redis calls an internal function to perform many background tasks, like # closing connections of clients in timeout, purging expired keys that are # never requested, and so forth. # # Not all tasks are performed with the same frequency, but Redis checks for # tasks to perform according to the specified "hz" value. # # By default "hz" is set to 10. Raising the value will use more CPU when # Redis is idle, but at the same time will make Redis more responsive when # there are many keys expiring at the same time, and timeouts may be # handled with more precision. # # The range is between 1 and 500, however a value over 100 is usually not # a good idea. Most users should use the default of 10 and raise this up to # 100 only in environments where very low latency is required. hz 10 # When a child rewrites the AOF file, if the following option is enabled # the file will be fsync-ed every 32 MB of data generated. This is useful # in order to commit the file to the disk more incrementally and avoid # big latency spikes. # aof rewrite過程中,是否採取增量文件同步策略,預設為“yes”。 rewrite過程中,每32M數據進行一次文件同步,這樣可以減少aof大文件寫入對磁碟的操作次數 aof-rewrite-incremental-fsync yes # redis數據存儲 redis的存儲分為記憶體存儲、磁碟存儲和log文件三部分,配置文件中有三個參數對其進行配置。 save seconds updates,save配置,指出在多長時間內,有多少次更新操作,就將數據同步到數據文件。可多個條件配合,預設配置了三個條件。 appendonly yes/no ,appendonly配置,指出是否在每次更新操作後進行日誌記錄,如果不開啟,可能會在斷電時導致一段時間內的數據丟失。因為redis本身同步數據文件是按上面的save條件來同步的,所以有的數據會在一段時間內只存在於記憶體中。 appendfsync no/always/everysec ,appendfsync配置,no表示等操作系統進行數據緩存同步到磁碟,always表示每次更新操作後手動調用fsync()將數據寫到磁碟,everysec表示每秒同步一次。View Code
1.5 依次將redis安裝目錄下的sentinel.conf,拷貝到後3個目錄下cp /root/redis-5.0.2/sentinel.conf /usr/local/redis-sentinel/7505/sentinel-7505.conf
1.6 依次修改新拷貝的3個sentinel.conf文件內容
daemonize yes
port 7505
#指定工作目錄
dir