Redis

2024-04-11 09:25| 来源: 网络整理| 查看: 265

文章目录 Redis之以经典的3节点方式部署哨兵集群1. 哨兵的配置文件2. 搭建过程2.1 配置2.2 启动哨兵进程2.3 检查哨兵状态 3. 哨兵节点管理3.1 哨兵节点增加与删除3.2 slave的永久下线3.3 slave切换为Master的优先级3.4 基于哨兵集群架构下的安全认证3.5 故障恢复 4. 哨兵的生产环境部署

Redis之以经典的3节点方式部署哨兵集群

Redis之Sentinal（哨兵） Redis之哨兵底层原理解析

1. 哨兵的配置文件

redis的解压目录下sentinel.conf为模板文件在这里插入图片描述最小的配置

每一个哨兵都可以去监控多个maser-slaves的主从架构

因为可能在公司里，为不同的项目，部署了多个master-slaves的redis主从集群

相同的一套哨兵集群，就可以去监控不同的多个redis主从集群

你自己给每个redis主从集群分配一个逻辑的名称，下文中的mymaster和resque均为逻辑名称，可根据实际需要自由配置

sentinel monitor mymaster 127.0.0.1 6379 2 sentinel down-after-milliseconds mymaster 60000 sentinel failover-timeout mymaster 180000 sentinel parallel-syncs mymaster 1 sentinel monitor resque 192.168.75.3 6380 4 sentinel down-after-milliseconds resque 10000 sentinel failover-timeout resque 180000 sentinel parallel-syncs resque 5

sentinel monitor mymaster 127.0.0.1 6379 类似这种配置，来指定对一个master的监控，给监控的master指定的一个名称，因为后面分布式集群架构里会讲解，可以配置多个master做数据拆分

sentinel down-after-milliseconds mymaster 60000 #1分钟 sentinel failover-timeout mymaster 180000 #3分钟 sentinel parallel-syncs mymaster 1

上面的三个配置，都是针对某个监控的master配置的，给其指定上面分配的名称即可

上面这段配置，就监控了两个master node

这是最小的哨兵配置，如果发生了master-slave故障转移，或者新的哨兵进程加入哨兵集群，那么哨兵会自动更新自己的配置文件

sentinel monitor master-group-name hostname port quorum

quorum：

至少多少个哨兵要一致同意，master进程挂掉了，或者slave进程挂掉了，或者要启动一个故障转移操作quorum是用来识别故障的，真正执行故障转移的时候，还是要在哨兵集群执行选举，选举一个哨兵进程出来执行故障转移操作假设有5个哨兵，quorum设置了2，那么如果5个哨兵中的2个都认为master挂掉了; 2个哨兵中的一个就会做一个选举，选举一个哨兵出来，执行故障转移; 如果5个哨兵中有3个哨兵都是运行的，那么故障转移就会被允许执行

down-after-milliseconds：超过多少毫秒跟一个redis实例断了连接，哨兵就可能认为这个redis实例挂了

parallel-syncs：新的master别切换之后，同时有多少个slave被切换到去连接新master，重新做同步，数字越低，花费的时间越多

假设部署的redis是1个master，4个slave

然后master宕机了，4个slave中有1个切换成了master，剩下3个slave就要挂到新的master上面去

这个时候，如果parallel-syncs是1，那么3个slave，一个一个地挂接到新的master上面去，1个挂接完，而且从新的master sync完数据之后，再挂接下一个

如果parallel-syncs是3，那么一次性就会把所有slave挂接到新的master上去

failover-timeout：执行故障转移的timeout超时时长

2. 搭建过程 2.1 配置

哨兵默认用26379端口，默认不能跟其他机器在指定端口连通，只能在本地访问执行命令

mkdir -p /var/sentinel/5000 mkdir -p /etc/sentinel

参考模板文件sentinel.conf修改配置内容修改如下，并重命名为5000.conf，将该文件放置到/etc/sentinel目录下

不包含注释的配置文件内容 master节点配置文件 port 5000 bind 192.168.75.143 dir /var/sentinel/5000 sentinel monitor mymaster 192.168.75.143 6379 2 sentinel down-after-milliseconds mymaster 30000 sentinel failover-timeout mymaster 60000 sentinel parallel-syncs mymaster 1

slave节点配置，IP 192.168.75.144和192.168.75.145均为slave节点IP

192.168.75.144机器下的/etc/sentinel/5000.conf文件内容

port 5000 bind 192.168.75.144 dir /var/sentinel/5000 sentinel monitor mymaster 192.168.75.143 6379 2 sentinel down-after-milliseconds mymaster 30000 sentinel failover-timeout mymaster 60000 sentinel parallel-syncs mymaster 1

192.168.75.145机器下的/etc/sentinel/5000.conf文件内容

port 5000 bind 192.168.75.145 dir /var/sentinel/5000 sentinel monitor mymaster 192.168.75.143 6379 2 sentinel down-after-milliseconds mymaster 30000 sentinel failover-timeout mymaster 60000 sentinel parallel-syncs mymaster 1 包含注释的配置文件内容 # Example sentinel.conf # *** IMPORTANT *** # # By default Sentinel will not be reachable from interfaces different than # localhost, either use the 'bind' directive to bind to a list of network # interfaces, or disable protected mode with "protected-mode no" by # adding it to this configuration file. # # Before doing that MAKE SURE the instance is protected from the outside # world via firewalling or other means. # # For example you may use one of the following: # bind 192.168.75.143 #修改成机器IP # # protected-mode no # port # The port that this sentinel instance will run on port 5000 # sentinel announce-ip # sentinel announce-port # # The above two configuration directives are useful in environments where, # because of NAT, Sentinel is reachable from outside via a non-local address. # # When announce-ip is provided, the Sentinel will claim the specified IP address # in HELLO messages used to gossip its presence, instead of auto-detecting the # local address as it usually does. # # Similarly when announce-port is provided and is valid and non-zero, Sentinel # will announce the specified TCP port. # # The two options don't need to be used together, if only announce-ip is # provided, the Sentinel will announce the specified IP and the server port # as specified by the "port" option. If only announce-port is provided, the # Sentinel will announce the auto-detected local IP and the specified port. # # Example: # # sentinel announce-ip 1.2.3.4 # dir # Every long running process should have a well-defined working directory. # For Redis Sentinel to chdir to /tmp at startup is the simplest thing # for the process to don't interfere with administrative tasks such as # unmounting filesystems. dir /var/sentinel/5000 #需要修改部分 # sentinel monitor # # Tells Sentinel to monitor this master, and to consider it in O_DOWN # (Objectively Down) state only if at least sentinels agree. # # Note that whatever is the ODOWN quorum, a Sentinel will require to # be elected by the majority of the known Sentinels in order to # start a failover, so no failover can be performed in minority. # # Slaves are auto-discovered, so you don't need to specify slaves in # any way. Sentinel itself will rewrite this configuration file adding # the slaves using additional configuration options. # Also note that the configuration file is rewritten when a # slave is promoted to master. # # Note: master name should not include special characters or spaces. # The valid charset is A-z 0-9 and the three characters ".-_". sentinel monitor mymaster 192.168.75.143 6379 2 #机器IP为需要修改部分 # sentinel auth-pass # # Set the password to use to authenticate with the master and slaves. # Useful if there is a password set in the Redis instances to monitor. # # Note that the master password is also used for slaves, so it is not # possible to set a different password in masters and slaves instances # if you want to be able to monitor these instances with Sentinel. # # However you can have Redis instances without the authentication enabled # mixed with Redis instances requiring the authentication (as long as the # password set is the same for all the instances requiring the password) as # the AUTH command will have no effect in Redis instances with authentication # switched off. # # Example: # # sentinel auth-pass mymaster MySUPER--secret-0123passw0rd # sentinel down-after-milliseconds # # Number of milliseconds the master (or any attached slave or sentinel) should # be unreachable (as in, not acceptable reply to PING, continuously, for the # specified period) in order to consider it in S_DOWN state (Subjectively # Down). # # Default is 30 seconds. sentinel down-after-milliseconds mymaster 30000 # sentinel parallel-syncs # # How many slaves we can reconfigure to point to the new slave simultaneously # during the failover. Use a low number if you use the slaves to serve query # to avoid that all the slaves will be unreachable at about the same # time while performing the synchronization with the master. sentinel parallel-syncs mymaster 1 # sentinel failover-timeout # # Specifies the failover timeout in milliseconds. It is used in many ways: # # - The time needed to re-start a failover after a previous failover was # already tried against the same master by a given Sentinel, is two # times the failover timeout. # # - The time needed for a slave replicating to a wrong master according # to a Sentinel current configuration, to be forced to replicate # with the right master, is exactly the failover timeout (counting since # the moment a Sentinel detected the misconfiguration). # # - The time needed to cancel a failover that is already in progress but # did not produced any configuration change (SLAVEOF NO ONE yet not # acknowledged by the promoted slave). # # - The maximum time a failover in progress waits for all the slaves to be # reconfigured as slaves of the new master. However even after this time # the slaves will be reconfigured by the Sentinels anyway, but not with # the exact parallel-syncs progression as specified. # # Default is 3 minutes. sentinel failover-timeout mymaster 180000 # SCRIPTS EXECUTION # # sentinel notification-script and sentinel reconfig-script are used in order # to configure scripts that are called to notify the system administrator # or to reconfigure clients after a failover. The scripts are executed # with the following rules for error handling: # # If script exits with "1" the execution is retried later (up to a maximum # number of times currently set to 10). # # If script exits with "2" (or an higher value) the script execution is # not retried. # # If script terminates because it receives a signal the behavior is the same # as exit code 1. # # A script has a maximum running time of 60 seconds. After this limit is # reached the script is terminated with a SIGKILL and the execution retried. # NOTIFICATION SCRIPT # # sentinel notification-script # # Call the specified notification script for any sentinel event that is # generated in the WARNING level (for instance -sdown, -odown, and so forth). # This script should notify the system administrator via email, SMS, or any # other messaging system, that there is something wrong with the monitored # Redis systems. # # The script is called with just two arguments: the first is the event type # and the second the event description. # # The script must exist and be executable in order for sentinel to start if # this option is provided. # # Example: # # sentinel notification-script mymaster /var/redis/notify.sh # CLIENTS RECONFIGURATION SCRIPT # # sentinel client-reconfig-script # # When the master changed because of a failover a script can be called in # order to perform application-specific tasks to notify the clients that the # configuration has changed and the master is at a different address. # # The following arguments are passed to the script: # # # # is currently always "failover" # is either "leader" or "observer" # # The arguments from-ip, from-port, to-ip, to-port are used to communicate # the old address of the master and the new address of the elected slave # (now a master). # # This script should be resistant to multiple invocations. # # Example: # # sentinel client-reconfig-script mymaster /var/redis/reconfig.sh 2.2 启动哨兵进程

在配置好的各台机器上分别启动哨兵进程，组成一个集群如果开启安全认证的话，执行命令不成功，所以就把安全认证关闭掉了关闭方法

redis-sentinel /etc/sentinel/5000.conf

在这里插入图片描述