MariaDB Galera Cluster 部署(如何快速部署MariaDB集羣)

MariaDB做爲Mysql的一個分支,在開源項目中已經普遍使用,例如大熱的openstack,因此,爲了保證服務的高可用性,同時提升系統的負載能力,集羣部署是必不可少的。html

##MariaDB Galera Cluster 介紹node

MariaDB集羣是MariaDB同步多主機集羣。它僅支持XtraDB/ InnoDB存儲引擎(雖然有對MyISAM實驗支持 - 看wsrep_replicate_myisam系統變量)。mysql

主要功能:linux

  • 同步複製
  • 真正的multi-master,即全部節點能夠同時讀寫數據庫
  • 自動的節點成員控制,失效節點自動被清除
  • 新節點加入數據自動複製
  • 真正的並行複製,行級
  • 用戶能夠直接鏈接集羣,使用感覺上與MySQL徹底一致

優點:web

  • 由於是多主,因此不存在Slavelag(延遲)
  • 不存在丟失事務的狀況
  • 同時具備讀和寫的擴展能力
  • 更小的客戶端延遲
  • 節點間數據是同步的,而Master/Slave模式是異步的,不一樣slave上的binlog多是不一樣的

技術:sql

Galera集羣的複製功能基於Galeralibrary實現,爲了讓MySQL與Galera library通信,特別針對MySQL開發了wsrep API。數據庫

Galera插件保證集羣同步數據,保持數據的一致性,靠的就是可認證的複製,工做原理以下圖:vim

q

當客戶端發出一個commit的指令,在事務被提交以前,全部對數據庫的更改都會被write-set收集起來,而且將 write-set 紀錄的內容發送給其餘節點。centos

write-set 將在每一個節點進行認證測試,測試結果決定着節點是否應用write-set更改數據。服務器

若是認證測試失敗,節點將丟棄 write-set ;若是認證測試成功,則事務提交。

1.安裝環境準備

安裝MariaDB集羣至少須要3臺服務器(若是隻有兩臺的話須要特殊配置,請參照官方文檔)

在這裏,我列出試驗機器的配置:

操做系統版本:centos7

node4:10.128.20.16 node5:10.128.20.17 node6:10.128.20.18

以第一行爲例,node4爲 hostname ,10.128.20.16爲 ip ,在三臺機器修改 /etc/hosts 文件,個人文件以下:

10.128.20.16 node4
10.128.20.17 node5
10.128.20.18 node6

爲了保證節點間相互通訊,須要禁用防火牆設置(若是須要防火牆,則參照官方網站增長防火牆信息設置)

在三個節點分別執行命令:

systemctl stop firewalld

而後將 /etc/sysconfig/selinuxselinux 設置成 disabled ,這樣初始化環境就完成了。

###2.安裝 MariaDB Galera Cluster

[root@node4 ~]# yum install -y mariadb mariadb-galera-server mariadb-galera-common galera rsync
[root@node5 ~]# yum install -y mariadb mariadb-galera-server mariadb-galera-common galera rsync
[root@node6 ~]# yum install -y mariadb mariadb-galera-server mariadb-galera-common galera rsync

###3.配置 MariaDB Galera Cluster

初始化數據庫服務,只在一個節點進行

[root@node4 mariadb]# systemctl start mariadb
[root@node4 mariadb]# mysql_secure_installation

NOTE: RUNNING ALL PARTS OF THIS SCRIPT IS RECOMMENDED FOR ALL MariaDB
      SERVERS IN PRODUCTION USE!  PLEASE READ EACH STEP CAREFULLY!

In order to log into MariaDB to secure it, we'll need the current
password for the root user.  If you've just installed MariaDB, and
you haven't set the root password yet, the password will be blank,
so you should just press enter here.

Enter current password for root (enter for none):
OK, successfully used password, moving on...

Setting the root password ensures that nobody can log into the MariaDB
root user without the proper authorisation.

Set root password? [Y/n]
New password:
Re-enter new password:
Password updated successfully!
Reloading privilege tables..
 ... Success!


By default, a MariaDB installation has an anonymous user, allowing anyone
to log into MariaDB without having to have a user account created for
them.  This is intended only for testing, and to make the installation
go a bit smoother.  You should remove them before moving into a
production environment.

Remove anonymous users? [Y/n] n
 ... skipping.

Normally, root should only be allowed to connect from 'localhost'.  This
ensures that someone cannot guess at the root password from the network.

Disallow root login remotely? [Y/n] y
 ... Success!

By default, MariaDB comes with a database named 'test' that anyone can
access.  This is also intended only for testing, and should be removed
before moving into a production environment.

Remove test database and access to it? [Y/n] n
 ... skipping.

Reloading the privilege tables will ensure that all changes made so far
will take effect immediately.

Reload privilege tables now? [Y/n] y
 ... Success!

Cleaning up...

All done!  If you've completed all of the above steps, your MariaDB
installation should now be secure.

Thanks for using MariaDB!

關閉數據庫,修改 /etc/my.cnf.d/galera.cnf

[root@node4 mariadb]# systemctl stop mariadb
[root@node4 ~]# vim /etc/my.cnf.d/galera.cnf

修改如下內容:

[mysqld]
......
wsrep_provider = /usr/lib64/galera/libgalera_smm.so
wsrep_cluster_address = "gcomm://node4,node5,node6"
wsrep_node_name = node4
wsrep_node_address=10.128.20.16
#wsrep_provider_options="socket.ssl_key=/etc/pki/galera/galera.key; socket.ssl_cert=/etc/pki/galera/galera.crt;"

提示:若是不用ssl的方式認證的話,請把 wsrep_provider_options 註釋掉。

將此文件複製到node五、node6,注意要把 wsrep_node_name wsrep_node_address 改爲相應節點的 hostname ip

###4.啓動 MariaDB Galera Cluster 服務

[root@node4 ~]# /usr/libexec/mysqld --wsrep-new-cluster --user=root &

觀察日誌:

[root@node4 ~]# tail -f /var/log/mariadb/mariadb.log

150701 19:54:17 [Note] WSREP: wsrep_load(): loading provider library 'none'
150701 19:54:17 [Note] /usr/libexec/mysqld: ready for connections.
Version: '5.5.40-MariaDB-wsrep'  socket: '/var/lib/mysql/mysql.sock'  port: 3306  MariaDB Server, wsrep_25.11.r4026

出現 ready for connections ,證實咱們啓動成功,繼續啓動其餘節點:

[root@node5 ~]# systemctl start mariadb
[root@node6 ~]# systemctl start mariadb

能夠查看 /var/log/mariadb/mariadb.log,在日誌能夠看到節點均加入了集羣中。

警告⚠:--wsrep-new-cluster 這個參數只能在初始化集羣使用,且只能在一個節點使用。

###5.查看集羣狀態

q

咱們能夠關注幾個關鍵的參數:

wsrep_connected = on 連接已開啓

wsrep_local_index = 1 在集羣中的索引值

wsrep_cluster_size =3 集羣中節點的數量

wsrep_incoming_addresses = 10.128.20.17:3306,10.128.20.16:3306,10.128.20.18:3306 集羣中節點的訪問地址

###6.驗證數據同步

咱們在node4上新建數據庫 galera_test ,而後在 node5 node6 上查詢,若是能夠查詢到 galera_test 這個庫,說明數據同步成功,集羣運行正常。

[root@node4 ~]# mysql  -uroot  -proot  -e  "create database galera_test"
[root@node5 ~]# mysql  -uroot  -proot  -e  "show databases"
+--------------------+
| Database           |
+--------------------+
| information_schema |
| galera_test        |
| mysql              |
| performance_schema |
+--------------------+
[root@node6 ~]# mysql  -uroot  -proot  -e  "show databases"
+--------------------+
| Database           |
+--------------------+
| information_schema |
| galera_test        |
| mysql              |
| performance_schema |
+--------------------+

至此,咱們的 MariaDB Galera Cluster 已經成功部署。

參考文章: [1]http://galeracluster.com/documentation-webpages/ [2]https://mariadb.com/kb/en/mariadb/getting-started-with-mariadb-galera-cluster/

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