keepalived 是集群管理中保证集群高可用的一个服务软件，用来防止单点故障。
keepalived 是以VRRP 协议为实现基础的，VRRP 全称VirtualRouter Redundancy Protocol，即虚拟路由冗余协议。虚拟路由冗余协议，可以认为是实现路由器高可用的协议，即将N 台提供相同功能的路由器组成一个路由器组，这个组里面有一个master 和多个backup，master 上面有一个对外提供服务的vip（该路由器所在局域网内其他机器的默认路由为该vip），master 会发组播，当backup 收不到vrrp 包时就认为master 宕掉了，这时就需要根据VRRP 的优先级来选举一个backup 当master。这样的话就可以保证路由器的高可用了。
keepalived 主要有三个模块，分别是core、check 和vrrp。
core 模块为keepalived 的核心，负责主进程的启动、维护以及全局配置文件的加载和解析。
check 负责健康检查，包括常见的各种检查方式。
vrrp 模块是来实现VRRP 协议的。
master1:192.168.132.121
master2:192.168.132.122
虚拟IP:192.168.132.120
双主环境
master1
master1 mysql> show slave status\G; *************************** 1. row *************************** Slave_IO_State: Waiting for master to send event Master_Host: 192.168.132.122 Master_User: replication Master_Port: 3306 Connect_Retry: 60 Master_Log_File: master-bin.000003 Read_Master_Log_Pos: 4975 Relay_Log_File: relay-log.000003 Relay_Log_Pos: 913 Relay_Master_Log_File: master-bin.000003 Slave_IO_Running: Yes Slave_SQL_Running: Yes Replicate_Do_DB: Replicate_Ignore_DB: Replicate_Do_Table: Replicate_Ignore_Table: Replicate_Wild_Do_Table: Replicate_Wild_Ignore_Table: Last_Errno: 0 Last_Error: Skip_Counter: 0 Exec_Master_Log_Pos: 4975 Relay_Log_Space: 2618 Until_Condition: None Until_Log_File: Until_Log_Pos: 0 Master_SSL_Allowed: No Master_SSL_CA_File: Master_SSL_CA_Path: Master_SSL_Cert: Master_SSL_Cipher: Master_SSL_Key: Seconds_Behind_Master: 0 Master_SSL_Verify_Server_Cert: No Last_IO_Errno: 0 Last_IO_Error: Last_SQL_Errno: 0 Last_SQL_Error: Replicate_Ignore_Server_Ids: Master_Server_Id: 2 Master_UUID: 662134df-a196-11e9-b432-000c2963fd11 Master_Info_File: /data/mysql/master.info SQL_Delay: 0 SQL_Remaining_Delay: NULL Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates Master_Retry_Count: 86400 Master_Bind: Last_IO_Error_Timestamp: Last_SQL_Error_Timestamp: Master_SSL_Crl: Master_SSL_Crlpath: Retrieved_Gtid_Set: 662134df-a196-11e9-b432-000c2963fd11:1-7 Executed_Gtid_Set: 63a7f26f-a196-11e9-a2b2-000c2991dd19:1-18, 662134df-a196-11e9-b432-000c2963fd11:1-7 Auto_Position: 1 Replicate_Rewrite_DB: Channel_Name:
master2
mysql> show slave status\G; *************************** 1. row *************************** Slave_IO_State: Waiting for master to send event Master_Host: 192.168.132.121 Master_User: replication Master_Port: 3306 Connect_Retry: 60 Master_Log_File: master-bin.000008 Read_Master_Log_Pos: 650 Relay_Log_File: relay-log.000008 Relay_Log_Pos: 865 Relay_Master_Log_File: master-bin.000008 Slave_IO_Running: Yes Slave_SQL_Running: Yes Replicate_Do_DB: Replicate_Ignore_DB: Replicate_Do_Table: Replicate_Ignore_Table: Replicate_Wild_Do_Table: Replicate_Wild_Ignore_Table: Last_Errno: 0 Last_Error: Skip_Counter: 0 Exec_Master_Log_Pos: 650 Relay_Log_Space: 2098 Until_Condition: None Until_Log_File: Until_Log_Pos: 0 Master_SSL_Allowed: No Master_SSL_CA_File: Master_SSL_CA_Path: Master_SSL_Cert: Master_SSL_Cipher: Master_SSL_Key: Seconds_Behind_Master: 0 Master_SSL_Verify_Server_Cert: No Last_IO_Errno: 0 Last_IO_Error: Last_SQL_Errno: 0 Last_SQL_Error: Replicate_Ignore_Server_Ids: Master_Server_Id: 1 Master_UUID: 63a7f26f-a196-11e9-a2b2-000c2991dd19 Master_Info_File: /data/mysql/master.info SQL_Delay: 0 SQL_Remaining_Delay: NULL Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates Master_Retry_Count: 86400 Master_Bind: Last_IO_Error_Timestamp: Last_SQL_Error_Timestamp: Master_SSL_Crl: Master_SSL_Crlpath: Retrieved_Gtid_Set: 63a7f26f-a196-11e9-a2b2-000c2991dd19:1-18 Executed_Gtid_Set: 63a7f26f-a196-11e9-a2b2-000c2991dd19:1-18, 662134df-a196-11e9-b432-000c2963fd11:1-7 Auto_Position: 1 Replicate_Rewrite_DB: Channel_Name: Master_TLS_Version:
2.1 开始安装keepalived
[root@master1 ~]# cd /usr/local/src/
[root@master1 src]# wget https://www.keepalived.org/software/keepalived-2.0.17.tar.gz
[root@master1 src]# tar -xf keepalived-2.0.17.tar.gz
[root@master1 src]# cd keepalived-2.0.17
[root@master1 keepalived-2.0.17]# yum install openssl* libnl‐dev* gcc-c++
[root@master1 keepalived-2.0.17]# ./configure --prefix=/usr/local/keepalived
[root@master1 keepalived-2.0.17]# make
[root@master1 keepalived-2.0.17]# make install
[root@master1 keepalived-2.0.17]# cd /usr/local/keepalived/sbin/
[root@master1 sbin]# ll
-rwxr-xr-x. 1 root root 2381368 Jul 9 11:59 keepalived
[root@master1 sbin]# cp keepalived /usr/sbin/
[root@master1 sbin]# ll /usr/sbin/keepalived
-rwxr-xr-x. 1 root root 2381368 Jul 9 12:01 /usr/sbin/keepalived
[root@master1 sbin]# systemctl list-unit-files|grep keepalived
[root@master1 sbin]# systemctl enable keepalived
[root@master1 sbin]# systemctl list-unit-files|grep keepalived
[root@master1 sbin]# mkdir /etc/keepalived
[root@master1 sbin]# cp /usr/local/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/
[root@master1 sbin]# ll /etc/keepalived/
-rw-r--r--. 1 root root 3550 Jul 9 12:06 keepalived.conf
root@master1 keepalived-2.0.17]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived global_defs { router_id db01 } vrrp_instance VI_1 { state BACKUP interface ens33 virtual_router_id 51 priority 100 nopreempt advert_int 1 authentication { auth_type PASS auth_pass 1111 } virtual_ipaddress { 192.168.132.120 } } virtual_server 192.168.132.120 3306 { delay_loop 6 persistence_timeout 50 protocol TCP real_server 192.168.132.121 3306 { notify_down /etc/keepalived/kill_keepalived.sh TCP_CHECK { connect_timeout 3 nb_get_retry 3 connect_port 3306 delay_before_retry 3 } } }
配置简介
global_defs 区域主要是配置故障发生时的通知对象以及机器标识 notification_email_from Alexandre.Cassen@firewall.loc //通知邮件从哪个地址发出 smtp_server 192.168.200.1 //通知邮件的smtp 地址 smtp_connect_timeout 30 //连接smtp 服务器的超时时间 router_id db01 // 标识本节点的字符串， 通常为hostname vrrp_skip_check_adv_addr vrrp_strict vrrp_garp_interval 0 vrrp_gna_interval 0 } vrrp_instance VI_1 {//VRRP 实例state MASTER // MASTER 或BACKUP，为了防止脑裂现象，主备均需要设置为backup 模式，master 模式会抢占VIP interface eth0 //节点固有IP（非VIP）的网卡，用来发VRRP 包 virtual_router_id 51 //取值在0-255 之间，用来区分多个instance 的VRRP 组播priority 100 //优先级，同一个vrrp_instance 的MASTER优先级必须比BACKUP 高nopreempt //非抢占，配合backup,防止切换后，主库服务恢复正常后，IP 漂移过来advert_int 1// MASTER 与BACKUP 负载均衡器之间同步检查的时间间隔，单位为秒。 authentication { auth_type PASS auth_pass 1111 } virtual_ipaddress { //虚拟ip 地址,可以有多个地址，每个地址占一行，不需要子网掩码 192.168.132.120 } } virtual_server 192.168.200.16 3306 { delay_loop 6 //健康检查间隔，单位为秒 persistence_timeout 50 // 会话保持时间，就是把用户请求转发给同一个服务器 protocol TCP //转发协议，有TCP 和UDP 两种，一般用TCP real_server 192.168.132.121 3306 { //真实服务器，包括IP和端口号 notify_down kill_keepalived.sh TCP_CHECK { #通过tcpcheck 判断RealServer 的健康状态 connect_timeout 3 #连接超时时间 nb_get_retry 3 #重连次数 delay_before_retry 3 #重连时间间隔 connect_port 3306 #检测端口 } } }
keepalived 服务配置
#设置不抢占模式（DB1 设置即可）
nopreempt
#虚拟路由标识，这个标识是一个数字(1‐255)，在一个VRRP
实例中主备服务器ID 必须一样
virtual_router_id 68
#优先级，数字越大优先级越高，在一个实例中主服务器优
先级要高于备服务器
priority 100 #从服务器99
#设置主备之间同步检查的时间间隔单位秒
advert_int 1
[root@master1 keepalived-2.0.17]# vim /etc/keepalived/kill_keepalived.sh
[root@master1 keepalived-2.0.17]# chmod +x /etc/keepalived/kill_keepalived.sh
#!/bin/bash kill -9 $(cat /var/run/keepalived.pid)
[root@master1 keepalived-2.0.17]# systemctl start keepalived
[root@master1 keepalived-2.0.17]# cat /var/run/keepalived.pid
16287
master2相同做法
配置文件
[root@master2 sbin]# cat /etc/keepalived/keepalived.conf
[root@master2 sbin]# cat /etc/keepalived/keepalived.conf ! Configuration File for keepalived bal_defs { router_id db02 } vrrp_instance VI_1 { state BACKUP interface ens33 virtual_router_id 51 priority 90 nopreempt advert_int 1 authentication { auth_type PASS auth_pass 1111 } virtual_ipaddress { 192.168.132.120 } } virtual_server 192.168.132.120 3306 { delay_loop 6 persistence_timeout 50 protocol TCP real_server 192.168.132.122 3306 { notify_down /etc/keepalived/kill_keepalived.sh TCP_CHECK { connect_timeout 3 nb_get_retry 3 connect_port 3306 delay_before_retry 3 } } }
[root@master2 ~]# systemctl status keepalived
[root@master2 ~]# ps -ef|grep keepalived
[root@master1 ~]# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN qlen 1 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000 link/ether 00:0c:29:91:dd:19 brd ff:ff:ff:ff:ff:ff inet 192.168.132.121/24 brd 192.168.132.255 scope global ens33 valid_lft forever preferred_lft forever inet 192.168.132.120/32 scope global ens33 #虚拟IP地址 valid_lft forever preferred_lft forever inet6 fe80::b469:7426:8024:a47c/64 scope link valid_lft forever preferred_lft forever 3: ens34: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000 link/ether 00:0c:29:91:dd:23 brd ff:ff:ff:ff:ff:ff inet 192.168.43.85/24 brd 192.168.43.255 scope global dynamic ens34 valid_lft 2810sec preferred_lft 2810sec inet 192.168.254.121/24 brd 192.168.254.255 scope global ens34 valid_lft forever preferred_lft forever inet6 fe80::4d8:1809:407a:5c0a/64 scope link valid_lft forever preferred_lft forever
master2查看
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN qlen 1 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000 link/ether 00:0c:29:63:fd:11 brd ff:ff:ff:ff:ff:ff inet 192.168.132.122/24 brd 192.168.132.255 scope global ens33 valid_lft forever preferred_lft forever inet6 fe80::5d18:db0b:8907:de34/64 scope link valid_lft forever preferred_lft forever 3: ens34: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000 link/ether 00:0c:29:63:fd:1b brd ff:ff:ff:ff:ff:ff inet 192.168.254.122/24 brd 192.168.254.255 scope global ens34 valid_lft forever preferred_lft forever inet6 fe80::c3d5:5055:468a:94f8/64 scope link valid_lft forever preferred_lft forever
授权后尝试使用192.168.132.20这个IP连接数据库
mysql> grant all on *.* to root@192.168.132.123 identified by ‘1234567‘; mysql> flush privileges;
[root@slave ~]# mysql -ureplication -h192.168.132.120 -p1234567
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| master1 |
| master2 |
| mysql |
| performance_schema |
| sys |
+--------------------+
关闭192.168.132.121的mysqld
[root@master1 ~]# systemctl stop mysqld
[root@master1 ~]# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN qlen 1 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000 link/ether 00:0c:29:91:dd:19 brd ff:ff:ff:ff:ff:ff inet 192.168.132.121/24 brd 192.168.132.255 scope global ens33 valid_lft forever preferred_lft forever inet6 fe80::b469:7426:8024:a47c/64 scope link valid_lft forever preferred_lft forever 3: ens34: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000 link/ether 00:0c:29:91:dd:23 brd ff:ff:ff:ff:ff:ff inet 192.168.43.85/24 brd 192.168.43.255 scope global dynamic ens34 valid_lft 3348sec preferred_lft 3348sec inet 192.168.254.121/24 brd 192.168.254.255 scope global ens34 valid_lft forever preferred_lft forever inet6 fe80::4d8:1809:407a:5c0a/64 scope link valid_lft forever preferred_lft forever
查看master2
[root@master2 ~]# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN qlen 1 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000 link/ether 00:0c:29:63:fd:11 brd ff:ff:ff:ff:ff:ff inet 192.168.132.122/24 brd 192.168.132.255 scope global ens33 valid_lft forever preferred_lft forever inet 192.168.132.120/32 scope global ens33 #虚拟IP已经转移过来 valid_lft forever preferred_lft forever inet6 fe80::5d18:db0b:8907:de34/64 scope link valid_lft forever preferred_lft forever 3: ens34: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000 link/ether 00:0c:29:63:fd:1b brd ff:ff:ff:ff:ff:ff inet 192.168.254.122/24 brd 192.168.254.255 scope global ens34 valid_lft forever preferred_lft forever inet6 fe80::c3d5:5055:468a:94f8/64 scope link valid_lft forever preferred_lft forever
使用slave连接
[root@slave ~]# mysql -uroot -h192.168.132.120 -p1234567 mysql> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | master1 | | master2 | | mysql | | performance_schema | | sys | +--------------------+
依然可以访问,双主的高可用配置完成
在master1开启MySQL和keepalive后,虚拟IP并不会抢占回来,是因为设置的是非抢占模式,防止虚拟IP跳动影响性能
原文：https://www.cnblogs.com/zyxnhr/p/11161365.html