LAMP-5:MHA高可用(mysql集群)
文章目录
- 1.简介
- 2. 搭建MHA
-
- 2.1 搭建一个一主两从的群组
- 2.2 配置server4管理节点
- 3. MHA高可用
-
- 3.1 手动迁移
- 3.2 自动迁移
1.简介
- MHA（Master High Availability）目前在 MySQL 高可用方面是一个相对成熟的解决方案，是一套优秀的作为 MySQL 高可用性环境下故障切换和主从提升的高可用软件。
- MHA分为管理节点(manage)和数据节点(node)
- 高可用体现在Mysql出现故障切换时，只需不到30秒即可完成，而且能巨大程度上保持数据的一致性
- 在一台master出现故障时，manage可以迅速将一台slave升级成master，并将其他salve指向新的master
- 本文实验是搭建一个单组复制组的集群架构，由server4作为MHA管理节点，server1作为复制组的master节点，server2，3作为slave节点。
2. 搭建MHA
2.1 搭建一个一主两从的群组
首先删data/，修改配置文件my.cnf，初始化：mysqld --initialize --user=mysql，启动mysql，mysql_secure_installation
server1:
[mysqld]
datadir=/usr/local/mysql/data
socket=/usr/local/mysql/data/mysql.sock
symbolic-links=0
server_id=1
gtid_mode=ON
enforce_gtid_consistency=ON
master_info_repository=TABLE
relay_log_info_repository=TABLE
log_slave_updates=ON
log_bin=binlog
binlog_format=ROW
mysql> grant replication slave on *.* to repl@'%' identified by 'lee';
Query OK, 0 rows affected, 1 warning (0.01 sec)
server2:
[mysqld]
datadir=/usr/local/mysql/data
socket=/usr/local/mysql/data/mysql.sock
symbolic-links=0
disabled_storage_engines="MyISAM,BLACKHOLE,FEDERATED,ARCHIVE,MEMORY"
server_id=2
gtid_mode=ON
enforce_gtid_consistency=ON
master_info_repository=TABLE
relay_log_info_repository=TABLE
log_slave_updates=ON
log_bin=binlog
binlog_format=ROW
mysql> CHANGE MASTER TO MASTER_HOST='172.25.38.1',MASTER_USER='repl',MASTER_PASSWORD='lee',MASTER_AUTO_POSITION=1;
Query OK, 0 rows affected, 2 warnings (0.03 sec)
mysql> start slave;
Query OK, 0 rows affected (0.04 sec)
server3:
[mysqld]
datadir=/usr/local/mysql/data
socket=/usr/local/mysql/data/mysql.sock
symbolic-links=0
disabled_storage_engines="MyISAM,BLACKHOLE,FEDERATED,ARCHIVE,MEMORY"
server_id=3
gtid_mode=ON
enforce_gtid_consistency=ON
master_info_repository=TABLE
relay_log_info_repository=TABLE
log_slave_updates=ON
log_bin=binlog
binlog_format=ROW
mysql> CHANGE MASTER TO MASTER_HOST='172.25.38.1',MASTER_USER='repl',MASTER_PASSWORD='lee',MASTER_AUTO_POSITION=1;
Query OK, 0 rows affected, 2 warnings (0.03 sec)
mysql> start slave;
Query OK, 0 rows affected (0.01 sec)
2.2 配置server4管理节点
准备文件：
yum install -y *.rpm
在server1，2，3上;yum install -y mha4mysql-node-0.58-0.el7.centos.noarch.rpm
在server4上,获取模板文件：tar zxf mha4mysql-manager-0.58.tar.gz
建立目录：mkdir /etc/masterha
进入模板目录：cd mha4mysql-manager-0.58/samples/conf/
导入至新建目录：cat masterha_default.cnf app1.cnf > /etc/masterha/app.cnf
新建目录：mkdir /etc/masterha/app1
编辑app.cnf：
[server default]
user=root
password=lee
ssh_user=root
repl_user=repl
repl_password=lee
master_binlog_dir= /usr/local/mysql/data
remote_workdir=/tmp
secondary_check_script= masterha_secondary_check -s 172.25.38.1 -s 172.25.38.2
ping_interval=3
# master_ip_failover_script= /script/masterha/master_ip_failover
# shutdown_script= /script/masterha/power_manager
# report_script= /script/masterha/send_report
# master_ip_online_change_script= /script/masterha/master_ip_online_change
manager_workdir=/etc/masterha/app1
manager_log=/etc/masterha/app1/manager.log
[server1]
hostname=172.25.38.1
[server2]
hostname=172.25.38.2
candidate_master=1
[server3]
hostname=172.25.38.3
no_master=1
做节点之间互相的免密,完成后执行脚本检测：masterha_check_ssh --conf=/etc/masterha/app.cnf
进入server1，给予root用户远程权限：
mysql> grant all on *.* to root@'%' identified by 'lee';
Query OK, 0 rows affected, 1 warning (0.01 sec)
mysql> flush privileges;
Query OK, 0 rows affected (0.01 sec)
检测用户权限：masterha_check_repl --conf=/etc/masterha/app.cnf
3. MHA高可用
MHA的故障切换过程，共包括以下的步骤：
- 配置文件检查阶段，这个阶段会检查整个集群配置文件的信息
- 宕机的master处理，这个阶段包括虚拟ip摘除操作，主机关机操作
- 复制dead master和最新slave相差的relay log，并保存到MHA Manager具体的目录下
- 识别含有最新更新的slave
- 应用从master保存的二进制日志事件（binlog events）
- 提升一个slave作为新的master进行复制
- 使其他的slave连接新的master进行复制
3.1 手动迁移
手动迁移master，从server1迁移到server2上：
masterha_master_switch --conf=/etc/masterha/app.cnf --master_state=alive --new_master_host=172.25.38.2 --new_master_port=3306 --orig_master_is_new_slave --running_updates_limit=10000
此时，server1由master转为指向server2的slave：
模拟server2的master dead，进行master转移
手动down掉作为master的server2：/etc/init.d/mysqld stop
在server4上执行master迁移：
masterha_master_switch --master_state=dead --conf=/etc/masterha/app.cnf --dead_master_host=172.25.38.2 --dead_master_port=3306 --new_master_host=172.25.38.1 --new_master_port=3306 --ignore_last_failover
迁移成功，此时master节点又回到了server1，
若要重新加回stop的server2，需要：/etc/init.d/mysqld start
再进入数据库指定master节点：CHANGE MASTER TO MASTER_HOST='172.25.38.1',MASTER_USER='repl',MASTER_PASSWORD='lee',MASTER_AUTO_POSITION=1;
打开slave：start slave;
3.2 自动迁移
准备两个脚本，修改其中地址，并给予权限chmod +x *:
cat /usr/local/bin/master_ip_failover
#!/usr/bin/env perl
use strict;
use warnings FATAL => 'all';
use Getopt::Long;
my (
$command, $ssh_user, $orig_master_host, $orig_master_ip,
$orig_master_port, $new_master_host, $new_master_ip, $new_master_port
);
my $vip = '172.25.38.100/24';
my $ssh_start_vip = "/sbin/ip addr add $vip dev eth0";
my $ssh_stop_vip = "/sbin/ip addr del $vip dev eth0";
GetOptions(
'command=s' => \$command,
'ssh_user=s' => \$ssh_user,
'orig_master_host=s' => \$orig_master_host,
'orig_master_ip=s' => \$orig_master_ip,
'orig_master_port=i' => \$orig_master_port,
'new_master_host=s' => \$new_master_host,
'new_master_ip=s' => \$new_master_ip,
'new_master_port=i' => \$new_master_port,
);
exit &main();
sub main {
print "\n\nIN SCRIPT TEST====$ssh_stop_vip==$ssh_start_vip===\n\n";
if ( $command eq "stop" || $command eq "stopssh" ) {
my $exit_code = 1;
eval {
print "Disabling the VIP on old master: $orig_master_host \n";
&stop_vip();
$exit_code = 0;
};
if ($@) {
warn "Got Error: $@\n";
exit $exit_code;
}
exit $exit_code;
}
elsif ( $command eq "start" ) {
my $exit_code = 10;
eval {
print "Enabling the VIP - $vip on the new master - $new_master_host \n";
&start_vip();
$exit_code = 0;
};
if ($@) {
warn $@;
exit $exit_code;
}
exit $exit_code;
}
elsif ( $command eq "status" ) {
print "Checking the Status of the script.. OK \n";
exit 0;
}
else {
&usage();
exit 1;
}
}
sub start_vip() {
`ssh $ssh_user\@$new_master_host \" $ssh_start_vip \"`;
}
sub stop_vip() {
return 0 unless ($ssh_user);
`ssh $ssh_user\@$orig_master_host \" $ssh_stop_vip \"`;
}
sub usage {
print
"Usage: master_ip_failover --command=start|stop|stopssh|status --orig_master_host=host --orig_master_ip=ip --orig_master_port=port --new_master_host=host --new_master_ip=ip --new_master_port=port\n";
}
cat master_ip_online_change
#!/usr/bin/env perl
use strict;
use warnings FATAL =>'all';
use Getopt::Long;
my $vip = '172.25.38.100/24';
my $ssh_start_vip = "/sbin/ip addr add $vip dev eth0";
my $ssh_stop_vip = "/sbin/ip addr del $vip dev eth0";
my $exit_code = 0;
my (
$command, $orig_master_is_new_slave, $orig_master_host,
$orig_master_ip, $orig_master_port, $orig_master_user,
$orig_master_password, $orig_master_ssh_user, $new_master_host,
$new_master_ip, $new_master_port, $new_master_user,
$new_master_password, $new_master_ssh_user,
);
GetOptions(
'command=s' => \$command,
'orig_master_is_new_slave' => \$orig_master_is_new_slave,
'orig_master_host=s' => \$orig_master_host,
'orig_master_ip=s' => \$orig_master_ip,
'orig_master_port=i' => \$orig_master_port,
'orig_master_user=s' => \$orig_master_user,
'orig_master_password=s' => \$orig_master_password,
'orig_master_ssh_user=s' => \$orig_master_ssh_user,
'new_master_host=s' => \$new_master_host,
'new_master_ip=s' => \$new_master_ip,
'new_master_port=i' => \$new_master_port,
'new_master_user=s' => \$new_master_user,
'new_master_password=s' => \$new_master_password,
'new_master_ssh_user=s' => \$new_master_ssh_user,
);
exit &main();
sub main {
#print "\n\nIN SCRIPT TEST====$ssh_stop_vip==$ssh_start_vip===\n\n";
if ( $command eq "stop" || $command eq "stopssh" ) {
# $orig_master_host, $orig_master_ip, $orig_master_port are passed.
# If you manage master ip address at global catalog database,
# invalidate orig_master_ip here.
my $exit_code = 1;
eval {
print "\n\n\n***************************************************************\n";
print "Disabling the VIP - $vip on old master: $orig_master_host\n";
print "***************************************************************\n\n\n\n";
&stop_vip();
$exit_code = 0;
};
if ($@) {
warn "Got Error: $@\n";
exit $exit_code;
}
exit $exit_code;
}
elsif ( $command eq "start" ) {
# all arguments are passed.
# If you manage master ip address at global catalog database,
# activate new_master_ip here.
# You can also grant write access (create user, set read_only=0, etc) here.
my $exit_code = 10;
eval {
print "\n\n\n***************************************************************\n";
print "Enabling the VIP - $vip on new master: $new_master_host \n";
print "***************************************************************\n\n\n\n";
&start_vip();
$exit_code = 0;
};
if ($@) {
warn $@;
exit $exit_code;
}
exit $exit_code;
}
elsif ( $command eq "status" ) {
print "Checking the Status of the script.. OK \n";
`ssh $orig_master_ssh_user\@$orig_master_host \" $ssh_start_vip \"`;
exit 0;
}
else {
&usage();
exit 1;
}
}
# A simple system call that enable the VIP on the new master
sub start_vip() {
`ssh $new_master_ssh_user\@$new_master_host \" $ssh_start_vip \"`;
}
# A simple system call that disable the VIP on the old_master
sub stop_vip() {
`ssh $orig_master_ssh_user\@$orig_master_host \" $ssh_stop_vip \"`;
}
sub usage {
print
"Usage: master_ip_failover --command=start|stop|stopssh|status --orig_master_host=host --orig_master_ip=ip --orig_master_port=port --new_master_host=host --new_master_ip=ip --new_master_port=port\n";
}
打开配置文件中的相关部分：
在server2上添加一个网段;ip addr add 172.25.38.100/24 dev eth0
在server1上测试可以成功登陆：
master节点设置为server1，不是的话执行：CHANGE MASTER TO MASTER_HOST='172.25.38.1',MASTER_USER='repl',MASTER_PASSWORD='lee',MASTER_AUTO_POSITION=1;
在管理节点manager上打开MHA并后台执行：masterha_manager --conf=/etc/masterha/app.cnf &
此时，stop掉server1的master，MHA控制下的master将自动落到备份master也就是server2上；
将server启动，重新指定其指向的master为serer2，即可
