1.2.2.1、安装配置说明

哨兵也是一台redis服务器，只是不对外提供任何服务，redis的bin目录下的redis-sentinel其实就是redis-server的软连接。

创建软连接

对 redis-sentinel做软连接(可以在任意目录执行redis-sentinel )

ln -s /usr/local/redis/bin/redis-cli /usr/local/bin/redis-cli ;
ln -s /usr/local/redis/bin/redis-sentinel /usr/local/bin/redis-sentinel ;
ln -s /usr/local/redis/bin/redis-server /usr/local/bin/redis-server ;

宝塔Linux面板安装的Linux修改命令如下：

ln -s /www/server/redis/src/redis-cli /usr/local/bin/redis-cli;
ln -s /www/server/redis/src/redis-sentinel /usr/local/bin/redis-sentinel;
ln -s /www/server/redis/src/redis-server /usr/local/bin/redis-server;

配置文件

在redis源码中找到 sentinel.conf 配置文件，我们把它移动到redis安装目录下然后修改配置，共有下面几个配置：

vim /user/local/redis/bin/sentinel.conf

核心配置参数：

#端口
port 26379

#后台启动
daemonize yes

#运行时PID文件
pidfile /var/run/redis-sentinel.pid

#日志文件(绝对路径)
logfile "/opt/app/redis6/sentinel.log"

#数据目录
dir /tmp/sentinel_26379

#监控的节点名字可以自定义，后边的2代表的：如果有俩个哨兵判断这个主节点挂了那这个主节点就挂了，通常设置为哨兵个数一半加一
sentinel monitor mymaster 127.0.0.1 6379 2

#哨兵连接主节点多长时间没有响应就代表主节点挂了，单位毫秒。默认30000毫秒，30秒。
sentinel down-after-milliseconds mymaster 30000

#在故障转移时，最多有多少从节点对新的主节点进行同步。这个值越小完成故障转移的时间就越长，这个值越大就意味着越多的从节点因为同步数据而暂时阻塞不可用
sentinel parallel-syncs mymaster 1

#在进行同步的过程中，多长时间完成算有效，单位是毫秒，默认值是180000毫秒，3分钟。
sentinel failover-timeout mymaster 180000

#禁止使用SENTINEL SET设置notification-script和client-reconfig-script
sentinel deny-scripts-reconfig yes

#此处必须设置为本机IP（外网IP），否则会使用自动发现IP，会出现访问内网IP情况，从而导致无法连通。
sentinel announce-ip [本机外网IP]

#手动注册sentinel的IP
sentinel announce-port 26379

最终配置参考：

# Example sentinel.conf

# By default protected mode is disabled in sentinel mode. Sentinel is reachable
# from interfaces different than localhost. Make sure the sentinel instance is
# protected from the outside world via firewalling or other means.
protected-mode no

# port <sentinel-port>
# The port that this sentinel instance will run on
# Redis Sentinel 启动端口
port 26379

# By default Redis Sentinel does not run as a daemon. Use 'yes' if you need it.
# Note that Redis will write a pid file in /var/run/redis-sentinel.pid when
# daemonized.
daemonize yes

# When running daemonized, Redis Sentinel writes a pid file in
# /var/run/redis-sentinel.pid by default. You can specify a custom pid file
# location here.
pidfile "/var/run/redis-sentinel.pid"

# Specify the log file name. Also the empty string can be used to force
# Sentinel 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 "/www/wwwlogs/redis-sentinel.log"

# sentinel announce-ip <ip>
# sentinel announce-port <port>
# 手动注册sentinel的端口
sentinel announce-port 26379

#
# 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
# 此处必须设置为本机IP（外网IP），否则会使用自动发现IP，会出现访问内网IP情况，从而导致无法连通。
sentinel announce-ip "192.168.3.67"

# dir <working-directory>
# 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.
# Sentinel 的工作目录
dir "/tmp"

# sentinel monitor <master-name> <ip> <redis-port> <quorum>
#
# Tells Sentinel to monitor this master, and to consider it in O_DOWN
# (Objectively Down) state only if at least <quorum> 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.
#
# Replicas are auto-discovered, so you don't need to specify replicas in
# any way. Sentinel itself will rewrite this configuration file adding
# the replicas using additional configuration options.
# Also note that the configuration file is rewritten when a
# replica 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 ".-_".
# Sentine监听的maste地址，第一个参数是给master起的名字，第二个参数为master IP，第三个为master端口，第四个为当该master挂了的时候，若想将该master判为失效，在Sentine集群中必须至少2个Sentine同意才行，只要该数量不达标，则就不会发生故障迁移。
sentinel monitor mymaster 192.168.3.67 16379 2

# sentinel auth-pass <master-name> <password>
#
# Set the password to use to authenticate with the master and replicas.
# Useful if there is a password set in the Redis instances to monitor.
#
# Note that the master password is also used for replicas, so it is not
# possible to set a different password in masters and replicas 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 auth-pass mymaster MXkepzK5ptxhdHR4
sentinel auth-user mymaster default
# sentinel auth-user <master-name> <username>
#
# This is useful in order to authenticate to instances having ACL capabilities,
# that is, running Redis 6.0 or greater. When just auth-pass is provided the
# Sentinel instance will authenticate to Redis using the old "AUTH <pass>"
# method. When also an username is provided, it will use "AUTH <user> <pass>".
# In the Redis servers side, the ACL to provide just minimal access to
# Sentinel instances, should be configured along the following lines:
#
#     user sentinel-user >somepassword +client +subscribe +publish \
#                        +ping +info +multi +slaveof +config +client +exec on

# sentinel down-after-milliseconds <master-name> <milliseconds>
#
# Number of milliseconds the master (or any attached replica 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.
# master在多长时间（默认30秒）内一直没有给Sentine返回有效信息,则认定该master主观下线,不能使用后标记为s_down状态
sentinel down-after-milliseconds mymaster 150000

# IMPORTANT NOTE: starting with Redis 6.2 ACL capability is supported for
# Sentinel mode, please refer to the Redis website https://redis.io/topics/acl
# for more details.

# Sentinel's ACL users are defined in the following format:
#
#   user <username> ... acl rules ...
#
# For example:
#
#   user worker +@admin +@connection ~* on >ffa9203c493aa99
#
# For more information about ACL configuration please refer to the Redis
# website at https://redis.io/topics/acl and redis server configuration
# template redis.conf.

# ACL LOG
#
# The ACL Log tracks failed commands and authentication events associated
# with ACLs. The ACL Log is useful to troubleshoot failed commands blocked
# by ACLs. The ACL Log is stored in memory. You can reclaim memory with
# ACL LOG RESET. Define the maximum entry length of the ACL Log below.
acllog-max-len 128

# Using an external ACL file
#
# Instead of configuring users here in this file, it is possible to use
# a stand-alone file just listing users. The two methods cannot be mixed:
# if you configure users here and at the same time you activate the external
# ACL file, the server will refuse to start.
#
# The format of the external ACL user file is exactly the same as the
# format that is used inside redis.conf to describe users.
#
# aclfile /etc/redis/sentinel-users.acl

# requirepass <password>
#
# You can configure Sentinel itself to require a password, however when doing
# so Sentinel will try to authenticate with the same password to all the
# other Sentinels. So you need to configure all your Sentinels in a given
# group with the same "requirepass" password. Check the following documentation
# for more info: https://redis.io/topics/sentinel
#
# IMPORTANT NOTE: starting with Redis 6.2 "requirepass" is a compatibility
# layer on top of the ACL system. The option effect will be just setting
# the password for the default user. Clients will still authenticate using
# AUTH <password> as usually, or more explicitly with AUTH default <password>
# if they follow the new protocol: both will work.
#
# New config files are advised to use separate authentication control for
# incoming connections (via ACL), and for outgoing connections (via
# sentinel-user and sentinel-pass)
#
# The requirepass is not compatible with aclfile option and the ACL LOAD
# command, these will cause requirepass to be ignored.

# sentinel sentinel-user <username>
#
# You can configure Sentinel to authenticate with other Sentinels with specific
# user name.

# sentinel sentinel-pass <password>
#
# The password for Sentinel to authenticate with other Sentinels. If sentinel-user
# is not configured, Sentinel will use 'default' user with sentinel-pass to authenticate.

# sentinel parallel-syncs <master-name> <numreplicas>
#
# How many replicas we can reconfigure to point to the new replica simultaneously
# during the failover. Use a low number if you use the replicas to serve query
# to avoid that all the replicas will be unreachable at about the same
# time while performing the synchronization with the master.
# 当在执行故障转移时，设置几个slave同时进行切换master，该值越大，则可能就有越多的slave在切换master时不可用，可以将该值设置为1，即一个一个来，这样在某个slave进行切换master同步数据时，其余的slave还能正常工作
sentinel parallel-syncs mymaster 1

# sentinel failover-timeout <master-name> <milliseconds>
#
# 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 replica 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 replica).
#
# - The maximum time a failover in progress waits for all the replicas to be
#   reconfigured as replicas of the new master. However even after this time
#   the replicas will be reconfigured by the Sentinels anyway, but not with
#   the exact parallel-syncs progression as specified.
#
# Default is 3 minutes.
# 执行故障迁移超时时间，即在指定时间内没有大多数的sentinel 反馈master下线，该故障迁移计划则失效
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 <master-name> <script-path>
#
# 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 <master-name> <script-path>
#
# 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:
#
# <master-name> <role> <state> <from-ip> <from-port> <to-ip> <to-port>
#
# <state> is currently always "start"
# <role> 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 replica
# (now a master).
#
# This script should be resistant to multiple invocations.
#
# Example:
#
# sentinel client-reconfig-script mymaster /var/redis/reconfig.sh

# SECURITY
#
# By default SENTINEL SET will not be able to change the notification-script
# and client-reconfig-script at runtime. This avoids a trivial security issue
# where clients can set the script to anything and trigger a failover in order
# to get the program executed.

sentinel deny-scripts-reconfig yes

# REDIS COMMANDS RENAMING (DEPRECATED)
#
# WARNING: avoid using this option if possible, instead use ACLs.
#
# Sometimes the Redis server has certain commands, that are needed for Sentinel
# to work correctly, renamed to unguessable strings. This is often the case
# of CONFIG and SLAVEOF in the context of providers that provide Redis as
# a service, and don't want the customers to reconfigure the instances outside
# of the administration console.
#
# In such case it is possible to tell Sentinel to use different command names
# instead of the normal ones. For example if the master "mymaster", and the
# associated replicas, have "CONFIG" all renamed to "GUESSME", I could use:
#
# SENTINEL rename-command mymaster CONFIG GUESSME
#
# After such configuration is set, every time Sentinel would use CONFIG it will
# use GUESSME instead. Note that there is no actual need to respect the command
# case, so writing "config guessme" is the same in the example above.
#
# SENTINEL SET can also be used in order to perform this configuration at runtime.
#
# In order to set a command back to its original name (undo the renaming), it
# is possible to just rename a command to itself:
#
# SENTINEL rename-command mymaster CONFIG CONFIG

# HOSTNAMES SUPPORT
#
# Normally Sentinel uses only IP addresses and requires SENTINEL MONITOR
# to specify an IP address. Also, it requires the Redis replica-announce-ip
# keyword to specify only IP addresses.
#
# You may enable hostnames support by enabling resolve-hostnames. Note
# that you must make sure your DNS is configured properly and that DNS
# resolution does not introduce very long delays.
#
sentinel resolve-hostnames no

# When resolve-hostnames is enabled, Sentinel still uses IP addresses
# when exposing instances to users, configuration files, etc. If you want
# to retain the hostnames when announced, enable announce-hostnames below.
#
sentinel announce-hostnames no

# When master_reboot_down_after_period is set to 0, Sentinel does not fail over
# when receiving a -LOADING response from a master. This was the only supported
# behavior before version 7.0.
#
# Otherwise, Sentinel will use this value as the time (in ms) it is willing to
# accept a -LOADING response after a master has been rebooted, before failing
# over.

启动Sentienl哨兵

# 方式一:
nohup redis-sentinel sentinel.conf &
# 方式二:
redis-server sentinel.conf --sentinel

宝塔Linux面板安装的Linux修改命令如下：

redis-sentinel /www/server/redis/sentinel.conf &

查看主从+哨兵情况：

redis-cli -h 127.0.0.1 -p 6379
auth xx
#查看主从信息
info replication
#查看哨兵情况
redis-cli -p 26379 info sentinel

检验测试：

• （1）停止Master1上的redis-server服务。

• （2）重新启动原先Master1上的redis-server服务。

• （3）查看是否出现Slave和Master切换的日志，如下图所示：

注意：sentinel announce-ip 一定要配置，不然sentinel自动获取IP（由于云服务器上自动获取内网IP，而导致无法访问），就会出现Master挂了之后，不能切换问题。

Redis-Sentinel 随机启动

脚本 + 服务启停方式（推荐）

创建 redis-sentinel 脚本

vi /etc/init.d/redis-sentinel

保存脚本内容：

#!/bin/sh
# Configurations injected by install_server below....
# redis-sentinel 命令路径
EXEC=/usr/local/bin/redis-sentinel
# redis-cli 命令路径
CLIEXEC=/usr/local/bin/redis-cli
# redis-sentinel 进程路径（与sentinel.conf中的pidfile一致）
PIDFILE=/var/run/redis-sentinel.pid
# sentinel.conf 文件路径
CONF="/www/server/redis/sentinel.conf"
# sentinel端口号
REDISPORT="26379"
case "$1" in
    start)
        if [ -f $PIDFILE ]
        then
            echo "$PIDFILE exists, process is already running or crashed"
        else
            echo "Starting Redis Sentinel..."
            $EXEC $CONF
        fi
        ;;
    stop)
        if [ ! -f $PIDFILE ]
        then
            echo "$PIDFILE does not exist, process is not running"
        else
            PID=$(cat $PIDFILE)
            echo "Stopping ..."
            $CLIEXEC -p $REDISPORT shutdown
            while [ -x /proc/${PID} ]
            do
                echo "Waiting for Redis Sentinel to shutdown ..."
                sleep 1
            done
            echo "Redis Sentinel stopped"
        fi
        ;;
    status)
        PID=$(cat $PIDFILE)
        if [ ! -x /proc/${PID} ]
        then
            echo 'Redis Sentinel is not running'
        else
            echo "Redis Sentinel is running ($PID)"
        fi
        ;;
    restart)
        $0 stop
        $0 start
        ;;
    *)
        echo "Please use start, stop, restart or status as first argument"
        ;;
esac

# 修改redis-sentinel文件的执行权限
chmod +x  /etc/init.d/redis-sentinel
chmod 755 /etc/init.d/redis-sentinel

注册服务

vi /lib/systemd/system/redis-sentinel.service

[Unit]
Description=Redis Sentinel
After=network.target

[Service]
Type=forking
PIDFile=/var/run/redis-sentinel.pid
ExecStartPost=/bin/sleep 0.1
ExecStart=/etc/init.d/redis-sentinel start
ExecReload=/etc/init.d/redis-sentinel restart
ExecStop=/etc/init.d/redis-sentinel stop
PrivateTmp=true

[Install]
WantedBy=multi-user.target

使用systemctl命令：

# 重载服务
systemctl daemon-reload
# 开机自启
systemctl enable redis-sentinel
# 启动
systemctl start redis-sentinel
# 重启
systemctl restart redis-sentinel
# 停止
systemctl stop redis-sentinel
# 查看状态
systemctl status redis-sentinel
# 关闭开机启动
systemctl disable redis-sentinel

服务启停方式（不推荐）

[Unit]
Description=Redis Sentinel
After=network.target

[Service]
Type=forking
PIDFile=/var/run/redis-sentinel.pid
ExecStart=/usr/local/bin/redis-sentinel /www/server/redis/sentinel.conf
ExecReload=/bin/kill -s HUP $MAINPID
ExecStop=/bin/kill -s QUIT $MAINPID
PrivateTmp=true

[Install]
WantedBy=multi-user.target

使用systemctl命令：

# 重载服务
systemctl daemon-reload
# 开机自启
systemctl enable redis-sentinel
# 启动
systemctl start redis-sentinel
# 重启
systemctl restart redis-sentinel
# 停止
systemctl stop redis-sentinel
# 查看状态
systemctl status redis-sentinel
# 关闭开机启动
systemctl disable redis-sentinel