一 keepalive介紹
1.1 keepalived 是什么
keepalived 是集群管理中保證集群高可用的一個服務軟件，用來防止單點故障。
1.2 keepalived 工作原理
keepalived 是以VRRP 協議為實現基礎的，VRRP 全稱VirtualRouter Redundancy Protocol，即虛擬路由冗余協議。虛擬路由冗余協議，可以認為是實現路由器高可用的協議，即將N 台提供相同功能的路由器組成一個路由器組，這個組里面有一個master 和多個backup，master 上面有一個對外提供服務的vip（該路由器所在局域網內其他機器的默認路由為該vip），master 會發組播，當backup 收不到vrrp 包時就認為master 宕掉了，這時就需要根據VRRP 的優先級來選舉一個backup 當master。這樣的話就可以保證路由器的高可用了。
keepalived 主要有三個模塊，分別是core、check 和vrrp。
core 模塊為keepalived 的核心，負責主進程的啟動、維護以及全局配置文件的加載和解析。
check 負責健康檢查，包括常見的各種檢查方式。
vrrp 模塊是來實現VRRP 協議的。
1.3 實驗環境
master1:192.168.132.121
master2:192.168.132.122
虛擬IP:192.168.132.120
雙主環境
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:
二 配置keepalive
2.1 開始安裝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
2.2 配置keepailve
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 } } }
配置簡介
global_defs 區域主要是配置故障發生時的通知對象以及機器標識 notification_email_from Alexandre.Cassen@firewall.loc //通知郵件從哪個地址發出 smtp_server 192.168.200.1 //通知郵件的smtp 地址 smtp_connect_timeout 30 //連接smtp 服務器的超時時間 router_id db01 // 標識本節點的字符串， 通常為hostname vrrp_skip_check_adv_addr vrrp_strict vrrp_garp_interval 0 vrrp_gna_interval 0 } vrrp_instance VI_1 {//VRRP 實例state MASTER // MASTER 或BACKUP，為了防止腦裂現象，主備均需要設置為backup 模式，master 模式會搶占VIP interface eth0 //節點固有IP（非VIP）的網卡，用來發VRRP 包 virtual_router_id 51 //取值在0-255 之間，用來區分多個instance 的VRRP 組播priority 100 //優先級，同一個vrrp_instance 的MASTER優先級必須比BACKUP 高nopreempt //非搶占，配合backup,防止切換后，主庫服務恢復正常后，IP 漂移過來advert_int 1// MASTER 與BACKUP 負載均衡器之間同步檢查的時間間隔，單位為秒。 authentication { auth_type PASS auth_pass 1111 } virtual_ipaddress { //虛擬ip 地址,可以有多個地址，每個地址占一行，不需要子網掩碼 192.168.132.120 } } virtual_server 192.168.200.16 3306 { delay_loop 6 //健康檢查間隔，單位為秒 persistence_timeout 50 // 會話保持時間，就是把用戶請求轉發給同一個服務器 protocol TCP //轉發協議，有TCP 和UDP 兩種，一般用TCP real_server 192.168.132.121 3306 { //真實服務器，包括IP和端口號 notify_down kill_keepalived.sh TCP_CHECK { #通過tcpcheck 判斷RealServer 的健康狀態 connect_timeout 3 #連接超時時間 nb_get_retry 3 #重連次數 delay_before_retry 3 #重連時間間隔 connect_port 3306 #檢測端口 } } }
keepalived 服務配置
#設置不搶占模式（DB1 設置即可）
nopreempt
#虛擬路由標識，這個標識是一個數字(1‐255)，在一個VRRP
實例中主備服務器ID 必須一樣
virtual_router_id 68
#優先級，數字越大優先級越高，在一個實例中主服務器優
先級要高於備服務器
priority 100 #從服務器99
#設置主備之間同步檢查的時間間隔單位秒
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 } } }
2.3 檢查狀態
[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 #虛擬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
三 驗證
授權后嘗試使用192.168.132.20這個IP連接數據庫
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 |
+--------------------+
關閉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 #虛擬IP已經轉移過來 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連接
[root@slave ~]# mysql -uroot -h192.168.132.120 -p1234567 mysql> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | master1 | | master2 | | mysql | | performance_schema | | sys | +--------------------+
依然可以訪問,雙主的高可用配置完成
在master1開啟MySQL和keepalive后,虛擬IP並不會搶占回來,是因為設置的是非搶占模式,防止虛擬IP跳動影響性能