Galera+Haproxy+Keepalived搭建MariaDB集群

通过Galera实现MariaDB/MySQL多活,前端由Haproxy和Keepalived实现负载和高可用,无疑是当前最主流的技术方案,本文主要讲述通过Galera搭建MariaDB多活的方案。

系统平台

操作系统:CentOS7.5

服务器配置

服务器IP 主机名 应用
10.10.100.101 MARIADB-A MariaDB-Galera-server
MariaDB-client
galera
10.10.100.102 MARIADB-B
10.10.100.103 MARIADB-C
10.10.100.201 HAPROXY-A haproxy
keepalived
10.10.100.202 HAPROXY-B

搭建Galera+MariaDB

条件:最少三个节点
原理:通过wresp协议在全局实现底层数据片复制、优于MHA
优点:节点间实时数据同步、方便横向扩展
特点:前端只需做负载均衡,无需程序做读写分离

注意事项

  • 禁用Selinux
  • 防火墙开放MariaDB和Galera的端口

准备工作

每个数据库节点配置相同的yum源,编辑文件/etc/yum.repos.d/mariadb.repo

[mariadb]
name = MariaDB
baseurl = http://yum.mariadb.org/10.0/centos7-amd64
gpgkey=https://yum.mariadb.org/RPM-GPG-KEY-MariaDB
gpgcheck=1

配置yum源的官方说明

安装MariaDB

yum -y install MariaDB-Galera-server MariaDB-client galera
systemctl enable mariadb
systemctl start mariadb

我的网络访问国外网站好慢,大家可以自己先在MariaDB官网下载相应的版本,然后配个本地源,但本文不讲述。

配置MariaDB

初始化MariaDB,每个节点都需要初始化一次,除了改密码(Mysql@123),其余步骤都按“y”。

mysql_secure_installation

关闭MariaDB:

/etc/init.d/mysql stop

配置Cluster

修改配置/etc/my.cnf

[client-server]

[mysqld_safe]
#log-error=/var/log/mariadb/mariadb.log
#pid-file=/var/run/mariadb/mariadb.pid

!includedir /etc/my.cnf.d

修改配置/etc/my.cnf.d/server.cnf

[server]

[mysqld]
bind-address = 10.10.100.101
#user=mysql
#datadir=/var/lib/mysql
#socket=/var/lib/mysql/mysql.sock
#symbolic-links=0
#skip-external-locking
#skip-name-resolve
innodb_file_per_table = on
max_connections = 4096
collation-server = utf8_general_ci
character-set-server=utf8

innodb_flush_method = O_DIRECT
wait_timeout = 28800
binlog_cache_size = 16M
max_allowed_packet = 64M
expire_logs_days = 30
sort_buffer_size = 128M
innodb_buffer_pool_size = 512M

[galera]
wsrep_on=ON
wsrep_provider="/usr/lib64/galera/libgalera_smm.so"
wsrep_cluster_address="gcomm://10.10.100.101,10.10.100.102,10.10.100.103"
wsrep_cluster_name="galera_cluster"
wsrep_node_address=10.10.100.101
wsrep_node_name=mysql-a
wsrep_slave_threads=1
wsrep_causal_reads=ON
wsrep_certify_nonPK=ON
wsrep_sst_method=rsync
#wsrep_sst_donor=msyql-a,mysql-b,mysql-c
#wsrep_sst_method=xtrabackup-v2
#wsrep_sst_auth=wsrepl:Mysql@123

binlog_format=row
default_storage_engine=InnoDB
innodb_autoinc_lock_mode=2
bind-address = 10.10.100.101
innodb_flush_log_at_trx_commit=0

[embedded]

[mariadb]

[mariadb-10.0]

当使用XtraBackup进行热备时,需要创建用于同步数据的账号,取消以上配置中wsrep_sst_method相关参数的注释并修改,XtraBackup安装包可在其官网下载。

mysql -uroot -pMysql@123
use mysql
update user set host='%' where host='localhost';
create user 'wsrepl'@'%' identified by 'Mysql@123';
grant all on *.* to 'wsrepl'@'%';
flush privileges;
exit

同步配置文件

同步完成后,一定要修改每个节点的bind-address、wsrep_node_address和wsrep_node_name。

for i in 2 3; do scp /etc/my.cnf.d/server.cnf root@10.10.100.10$i:/etc/my.cnf.d/; done

启动集群

初始化cluster,不要在其他节点上执行该命令。当集群中所有节点都关闭后,需要重新初始化。

mysqld_safe --defaults-file=/etc/my.cnf.d/server.cnf --user=mysql --wsrep-new-cluster &

启动其他节点数据库:

mysqld_safe --defaults-file=/etc/my.cnf.d/server.cnf --user=mysql &

其他可能涉及到的优化

修改hosts:

echo -e "mariadb-a 10.10.100.101\nmariadb-b 10.10.100.102\nmariadb-c 10.10.100.103" >> /etc/hosts

/etc/security/limits.conf添加:

* soft nofile 65536
* hard nofile 65536

/etc/sysctl.conf添加:

fs.file-max = 655350
net.ipv4.ip_local_port_range = 1025 65000
net.ipv4.tcp_tw_recycle = 1

问题思考

1.如果出现网络故障导致脑裂,该如何处理?

可以尝试:set global wsrep_provider_options="pc.bootstrap=true";

2.使用xtrabackup方式同步时,需要注意哪些事项?

每个MariaDB需要创建用于同步数据的账号

3.当所有节点都关闭后,怎么重启Cluster?

首先,在任意一台主机上编辑/var/lib/mysql/grastate.dat,修改 seqno 的值,将“-1”改为“1”
然后,正常启动集群“galera_new_cluster
最后,通过“/etc/init.d/mysql start”启动其他节点

搭建Haproxy+Keepalived

安装过程略,搭建成功后,应用通过VIP连接数据库,由Haproxy担任负载均衡、Galera担任数据同步。

配置Haproxy

修改配置/etc/haproxy/haproxy.cfg

global
    log 127.0.0.1 local2
    chroot /var/lib/haproxy
    pidfile /var/run/haproxy.pid
    maxconn 4000
    user haproxy
    group haproxy
    daemon
    spread-checks              3
    tune.bufsize               32768
    tune.maxrewrite 1024
    tune.ssl.default-dh-param  2048
    stats socket /var/lib/haproxy/stats

defaults
    log global
    log 127.0.0.1 local3
    mode http
    option tcplog
    option dontlognull
    retries 10
    option redispatch
    timeout http-request 10s
    timeout queue 1m 
    timeout connect 10s 
    timeout client 1m
    timeout server 1m
    timeout http-keep-alive 10s
    timeout check 10s
    maxconn 3000
    contimeout 5000
    clitimeout 50000
    srvtimeout 50000

listen mariadb
    bind 10.10.100.200:3306
    mode tcp
    balance roundrobin
    server mariadb-a 10.10.100.101:3306 weight 5
    server mariadb-b 10.10.100.102:3306 weight 5
    server mariadb-c 10.10.100.103:3306 weight 5
    #balance source
    #hash-type consistent
    #option  tcplog
    #option  clitcpka
    #option  srvtcpka
    #option  httpchk
    #timeout client    28800s
    #timeout server    28800s
    #server  mariadb-a 10.10.100.101:3306 inter 30s fastinter 3s downinter 3s rise 3 fall 3
    #server  mariadb-b 10.10.100.102:3306 inter 30s fastinter 3s downinter 3s rise 3 fall 3 backup
    #server  mariadb-c 10.10.100.103:3306 inter 30s fastinter 3s

listen stats
    bind 10.10.100.200:1080
    mode http
    option httplog
    maxconn 10
    stats enable
    stats refresh 30s
    stats uri /stats
    stats realm MaCluster\ Haproxy
    stats auth admin:admin
    stats hide-version
    stats admin if TRUE

配置keepalived

为了防止脑裂,将两台Keepalive的state都设为BACKUP、proiority必须小于100,修改配置/etc/keepalived/keepalived.conf

global_defs {
    router_id HAPROXY
}

vrrp_script chk_haproxy {
    script "/etc/keepalived/chk_haproxy.sh"
    interval 1
    weight 2
}

vrrp_instance VI_1 {
    state BACKUP
    interface ens33
    virtual_router_id 201
    priority 90
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    track_script {
        chk_haproxy
    }
    virtual_ipaddress {
        10.10.100.200/24
    }
    track_interface {
        ens33
    }
}

注意:需要修改interface(如果网卡名不同)、priority和virtual_router_id。

配置监控脚本

Haproxy的进程监控脚本,如果haproxy进程不存在,则自动关闭keepalived。

网上有说监控脚本不执行,但本人的配置和脚本是正常的,有图为证:

编辑脚本/etc/keepalived/chk_haproxy.sh

#!/bin/bash
chkha=`ps -C haproxy --no-header |wc -l`
if [ $chkha -eq 0 ];then
systemctl stop keepalived
fi

原创文章禁止转载:技术学堂 » Galera+Haproxy+Keepalived搭建MariaDB集群

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