MHA羣集管理

時間  2019-11-06
標籤 mha 羣集 管理 简体版
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MHA羣集管理

環境：

192.168.205.37: as MHA server
192.168.205.47: as Master server
192.168.205.57: as Slave1 server
192.168.205.67: as Slave2 servernode

版本：

OS: centos 7 1810 with mini install
mariadb-server 5.5.60
mha4mysql-manager-0.56-0.el6.noarch.rpm
mha4mysql-node-0.56-0.el6.noarch.rpmmysql

目地：

MHA使用perl腳本寫的程序，當主節點down時若是從節點複製沒有完成時，當他成爲主節點後，它須要嘗試將主節點的二進制日誌複製到新的主節點，從而保證數據的完整性，因此它須要sshkey驗證。咱們使用一臺作爲管理節點，其中三個爲數據庫節點，一主兩從，模擬主節點down機，看從是如何被提高爲主節點的。sql

安裝數據庫

  1. 安裝mariadb使用以下腳本： 
    [root@master data]#cat maridb_yum.sh 
#!/bin/bash
ID=`ip a show dev eth0 | sed -r '3!d;s@(.*inet)(.*)(/.*)@\2@' | cut -d. -f4`
rpm -q mariadb-server ||yum install -y mariadb-server
[ -d /data/mysql ] || mkdir -p /data/mysql
[ -d /data/logs ] || mkdir -p /data/logs
chown mysql:mysql /data/{mysql,logs}
sed -i 's@datadir=/var/lib/mysql@datadir=/data/mysql@' /etc/my.cnf
grep "log-bin" /etc/my.cnf || sed -i '/\[mysqld\]/a log-bin=/data/logs/bin' /etc/my.cnf
grep "innodb_file_per_table" /etc/my.cnf || sed -i '/\[mysqld\]/a innodb_file_per_table = on' /etc/my.cnf
grep "skip_name_resolve" /etc/my.cnf || sed -i '/\[mysqld\]/a skip_name_resolve = on' /etc/my.cnf
grep "server-id" /etc/my.cnf || sed -i "/\[mysqld\]/a server-id=$ID" /etc/my.cnf
service mariadb restart
  2. 修改兩個從節點的配置文件 
    [root@slave1 data]#vi /etc/my.cnf
[mysqld]
read_only   
relay_log_purge=0     #不刪除中繼日誌

  3. 創建主節點的複製位置和賬號數據庫

    MariaDB [(none)]> show master logs;
+------------+-----------+
| Log_name   | File_size |
+------------+-----------+
| bin.000001 |     30373 |
| bin.000002 |   1038814 |
| bin.000003 |       245 |
+------------+-----------+
3 rows in set (0.00 sec)

MariaDB [(none)]> grant replication slave on *.* to repluser@'192.168.205.%' identified by 'centos';
Query OK, 0 rows affected (0.00 sec)
MariaDB [(none)]> grant all on *.* to mhauser@'192.168.205.%' identified by 'centos'; 
Query OK, 0 rows affected (0.00 sec)

  4. 配置從節點的change master to並啓動線程vim

    MariaDB [(none)]> CHANGE MASTER TO
    ->   MASTER_HOST='192.168.205.47',
    ->   MASTER_USER='repluser',
    ->   MASTER_PASSWORD='centos',
    ->   MASTER_PORT=3306,
    ->   MASTER_LOG_FILE='bin.000003',
    ->   MASTER_LOG_POS=245;
Query OK, 0 rows affected (0.01 sec)

MariaDB [(none)]> start slave;
Query OK, 0 rows affected (0.00 sec)
MariaDB [(none)]> show slave status\G
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 192.168.205.47
                  Master_User: repluser
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: bin.000003
          Read_Master_Log_Pos: 401
               Relay_Log_File: mariadb-relay-bin.000002
                Relay_Log_Pos: 679
        Relay_Master_Log_File: bin.000003
             Slave_IO_Running: Yes
            Slave_SQL_Running: Yes

    MHA實現

  5. 安裝包，mha依賴epel源，咱們要把epel起用 
    [root@MHA ~]#yum install mha4mysql-manager-0.56-0.el6.noarch.rpm mha4mysql-node-0.56-0.el6.noarch.rpm
  6. 在全部的sql節點上安裝node包 
    [root@master ~]#yum install mha4mysql-node-0.56-0.el6.noarch.rpm 
[root@slave1 data]#yum install mha4mysql-node-0.56-0.el6.noarch.rpm 
[root@slave2 data]#yum install mha4mysql-node-0.56-0.el6.noarch.rpm
  7. 配置ssh key 驗證 
    [root@MHA ~]#ssh-keygen 
[root@MHA ~]#ssh-copy-id 192.168.205.37
[root@MHA ~]#cat .ssh/authorized_keys 
[root@MHA ~]#scp -r .ssh 192.168.205.47:/root/
[root@MHA ~]#scp -r .ssh 192.168.205.57:/root/
[root@MHA ~]#scp -r .ssh 192.168.205.67:/root/
  8. 生成配置MHA文件 
    [root@MHA ~]#mkdir /etc/mha
[root@MHA ~]#vim /etc/mha/app1.cnf
[server default]
master_binlog_dir=/data/logs/ 
user=mhauser
password=centos
manager_workdir=/data/mastermha/app1/
manager_log=/data/mastermha/app1/manager.log
remote_workdir=/data/mastermha/app1/
ssh_user=root
repl_user=repluser
repl_password=centos
ping_interval=1
[server1]
hostname=192.168.205.47
candidate_master=1
[server2]                                                                                                                          
hostname=192.168.205.57
[server3]
hostname=192.168.205.67
candidate_master=1
  9. 啓動以前進行檢查ssh，repl複製是否準備好 
    [root@MHA ~]#masterha_check_ssh --conf=/etc/mha/app1.cnf
[root@MHA ~]#masterha_check_repl --conf=/etc/mha/app1.cnf
  10. 起動進程，此進程前臺運行，當主節點失敗時切換完成後它會終止，因此要想持續要重啓進程 
    [root@MHA ~]#masterha_manager --conf=/etc/mha/app1.cnf
Mon Aug 12 23:33:22 2019 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping.
Mon Aug 12 23:33:22 2019 - [info] Reading application default configuration from /etc/mha/app1.cnf..
Mon Aug 12 23:33:22 2019 - [info] Reading server configuration from /etc/mha/app1.cnf..

    測試

  11. 咱們模擬一個正在寫入操做時，主節點down, 看服務器能不能正常切換並不能複製丟失的數據centos

    MariaDB [(none)]> use test;
Database changed
MariaDB [test]> create table testlog (id int auto_increment primary key,name char(10),age int default 20);

Query OK, 0 rows affected (0.01 sec)

MariaDB [test]> 
MariaDB [test]> delimiter $$
MariaDB [test]> 
MariaDB [test]> create procedure  sp_testlog() 
    -> begin  
    -> declare i int;
    -> set i = 1; 
    -> while i <= 100000 
    -> do  insert into testlog(name,age) values (concat('wang',i),i); 
    -> set i = i +1; 
    -> end while; 
    -> end$$
Query OK, 0 rows affected (0.00 sec)

MariaDB [test]> 
MariaDB [test]> delimiter ;
MariaDB [test]> call sp_testlog;
  12. 正在寫入數據時咱們及時關閉47服務器，MHA檢測到節點，並響應，成功提高其它的爲主後退出程序。 
    [root@MHA ~]#masterha_manager --conf=/etc/mha/app1.cnf
Mon Aug 12 23:33:22 2019 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping.
Mon Aug 12 23:33:22 2019 - [info] Reading application default configuration from /etc/mha/app1.cnf..
Mon Aug 12 23:33:22 2019 - [info] Reading server configuration from /etc/mha/app1.cnf..
Mon Aug 12 23:45:16 2019 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping.
Mon Aug 12 23:45:16 2019 - [info] Reading application default configuration from /etc/mha/app1.cnf..
Mon Aug 12 23:45:16 2019 - [info] Reading server configuration from /etc/mha/app1.cnf..
[root@MHA ~]#

  13. 咱們能夠查看日誌看一下發生的狀況，slave2提高爲主bash

    [root@MHA data]#cat mastermha/app1/manager.log 
----- Failover Report -----

app1: MySQL Master failover 192.168.205.47(192.168.205.47:3306) to 192.168.205.67(192.168.205.67:3306) succeeded

Master 192.168.205.47(192.168.205.47:3306) is down!

Check MHA Manager logs at MHA:/data/mastermha/app1/manager.log for details.

Started automated(non-interactive) failover.
The latest slave 192.168.205.57(192.168.205.57:3306) has all relay logs for recovery.
Selected 192.168.205.67(192.168.205.67:3306) as a new master.
192.168.205.67(192.168.205.67:3306): OK: Applying all logs succeeded.
192.168.205.57(192.168.205.57:3306): This host has the latest relay log events.
Generating relay diff files from the latest slave succeeded.
192.168.205.57(192.168.205.57:3306): OK: Applying all logs succeeded. Slave started, replicating from 192.168.205.67(192.168.205.67:3306)
192.168.205.67(192.168.205.67:3306): Resetting slave info succeeded.
Master failover to 192.168.205.67(192.168.205.67:3306) completed successfully.
  14. 咱們來覈實一下，在slave2上看一下slave的狀態，發現已經沒了，由於它是主 
    MariaDB [(none)]> show slave status\G
Empty set (0.00 sec)
  15. 檢查一下slave1，發現主節點指向了slave2 
    MariaDB [test]> show slave status\G
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 192.168.205.67
                  Master_User: repluser
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: bin.000005
          Read_Master_Log_Pos: 245
               Relay_Log_File: mariadb-relay-bin.000002
                Relay_Log_Pos: 523
        Relay_Master_Log_File: bin.000005
             Slave_IO_Running: Yes
            Slave_SQL_Running: Yes
  16. 在新主節點上看一下是否將read_only off掉，發現是，但不要忘記改回配置文件，若是重啓的話又會變成read_only 
    MariaDB [(none)]> show variables like 'read_only';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| read_only     | OFF   |
+---------------+-------+
1 row in set (0.00 sec)
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