Redis哨兵+keepalived高可用

redis哨兵高可用

基本環境

1：VIP隨MASTER飄動，無需手動改

2：主從關系切換由sentinel管理

3：keepalived三個state全部設定為BACKUP，如果role:master的話，優先級+10（默認三個優先級全為100），不能開啟nopreempt，否則只要keepalived運行，就不會釋放VIP（即使這個節點已經變為redis-slave了）

systemd服務管理

Redis

[Unit]
Description=Redis
After=network.target

[Service]
Type=forking
PIDFile=/var/run/redis.pid
ExecStart=/opt/redis-6.2.1/src/redis-server /opt/redis-6.2.1/redis.conf
ExecReload=/bin/kill -s HUP $MAINPID
ExecStop=/opt/redis-6.2.1/src/redis-cli -a password shutdown
[Install]
WantedBy=multi-user.target

Sentinel

[Unit]
Description=Sentinel
After=network.target
[Service]
Type=forking
PIDFile=/var/run/sentinel.pid
ExecStart=/opt/redis-6.2.1/src/redis-sentinel /opt/redis-6.2.1/sentinel.conf
ExecReload=/bin/kill -s HUP $MAINPID
ExecStop=/bin/kill -s QUIT $MAINPID
PrivateTmp=true
[Install]
WantedBy=multi-user.target

Redis配置

初始時，db02,db03需要在組態檔中寫slaveof db01，后續sentinel會自動去改

db01-redis

daemonize yes
bind 0.0.0.0
port 6379
timeout 300
loglevel notice
logfile "/opt/redis-6.2.1/redis.log"
pidfile "/var/run/redis.pid"
databases 16
save 900 1
save 300 10
save 60 10000
dbfilename "dump.rdb"
rdbcompression yes
dir "/opt/redis-6.2.1"
maxclients 20480
appendonly no
appendfsync no
requirepass "password"
masterauth "password"

db02-redis

daemonize yes
bind 0.0.0.0
port 6379
timeout 300
loglevel notice
logfile "/opt/redis-6.2.1/redis.log"
pidfile "/var/run/redis.pid"
databases 16
save 900 1
save 300 10
save 60 10000
dbfilename "dump.rdb"
rdbcompression yes
dir "/opt/redis-6.2.1"
maxclients 20480
appendonly no
appendfsync no
requirepass "password"
masterauth "password"
slaveof 192.168.0.51 6379

db03-redis

daemonize yes
bind 0.0.0.0
port 6379
timeout 300
loglevel notice
logfile "/opt/redis-6.2.1/redis.log"
pidfile "/var/run/redis.pid"
databases 16
save 900 1
save 300 10
save 60 10000
dbfilename "dump.rdb"
rdbcompression yes
dir "/opt/redis-6.2.1"
maxclients 20480
appendonly no
appendfsync no
requirepass "password"
masterauth "password"
slaveof 192.168.0.51 6379

sentinel配置

db01-sentinel

protected-mode no
port 26379
daemonize yes
logfile "/opt/redis-6.2.1/sentinel.log"
pidfile "/var/run/sentinel.pid"
dir "/tmp"
sentinel monitor mymaster 192.168.0.51 6379 1 #只要一個節點認為master有問題，即可發送failover
sentinel down-after-milliseconds mymaster 5000
sentinel auth-pass mymaster password

db02-sentinel

protected-mode no
port 26379
daemonize yes
logfile "/opt/redis-6.2.1/sentinel.log"
pidfile "/var/run/sentinel.pid"
dir "/tmp"
sentinel monitor mymaster 192.168.0.51 6379 1
sentinel down-after-milliseconds mymaster 5000
sentinel auth-pass mymaster password

db03-sentinel

protected-mode no
port 26379
daemonize yes
logfile "/opt/redis-6.2.1/sentinel.log"
pidfile "/var/run/sentinel.pid"
dir "/tmp"
sentinel monitor mymaster 192.168.0.51 6379 1
sentinel down-after-milliseconds mymaster 5000
sentinel auth-pass mymaster password

keepalived配置

將IP換了即可，三個節點全部設定為BACKUP，但是不能設定為nopreempt

db01-keepalived

! Configuration File for keepalived
global_defs {
   router_id LVS_DEVEL
   script_user root
   enable_script_security
   vrrp_skip_check_adv_addr
   #vrrp_strict
   vrrp_garp_interval 0
   vrrp_gna_interval 0
}
vrrp_script sentinel_check {
    script "/etc/keepalived/sentinel-check.sh 127.0.0.1 6379 password"
    interval 2
    weight 10
    fall 3
    rise 1
}
vrrp_instance VI_1 {
    state BACKUP ##
    interface ens33
    virtual_router_id 51
    priority 100
#    nopreempt  # 這里不要開nopreempt,只要keepalived在運行，會一直霸占VIP，我們要讓VIP飄
    advert_int 2
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    unicast_src_ip 192.168.0.51
    unicast_peer {
        192.168.0.52
        192.168.0.53
    virtual_ipaddress {
        192.168.0.55/24
    }
    track_script {
        sentinel_check
    }
}

db02-keepalived

! Configuration File for keepalived
global_defs {
   router_id LVS_DEVEL
   script_user root
   enable_script_security
   vrrp_skip_check_adv_addr
   #vrrp_strict
   vrrp_garp_interval 0
   vrrp_gna_interval 0
}
vrrp_script sentinel_check {
    script "/etc/keepalived/sentinel-check.sh 127.0.0.1 6379 password"
    interval 2
    weight 10
    fall 3
    rise 1
}
vrrp_instance VI_1 {
    state BACKUP ####
    interface ens33
    virtual_router_id 51
    priority 100
#    nopreempt
    advert_int 2
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    unicast_src_ip 192.168.0.52
    unicast_peer {
        192.168.0.51
        192.168.0.53
    }
    virtual_ipaddress {
	192.168.0.55/24
    }
    track_script {
    	sentinel_check
    }
}

db03-keepalived

! Configuration File for keepalived
global_defs {
   router_id LVS_DEVEL
   script_user root
   enable_script_security
   vrrp_skip_check_adv_addr
   #vrrp_strict
   vrrp_garp_interval 0
   vrrp_gna_interval 0
}
vrrp_script sentinel_check {
    script "/etc/keepalived/sentinel-check.sh 127.0.0.1 6379 password"
    interval 2
    weight 10
    fall 3
    rise 1
}
vrrp_instance VI_1 {
    state BACKUP
    interface ens33
    virtual_router_id 51
    priority 100
#    nopreempt
    advert_int 2
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    unicast_src_ip 192.168.0.53
    unicast_peer {
        192.168.0.52
        192.168.0.51
    }
    virtual_ipaddress {
	192.168.0.55/24
    }
    track_script {
    	sentinel_check
    }
}

使用說明

1：三臺節點啟動redis
2：三臺節點啟動sentinel
3: 三臺節點啟動keepalived