一、簡介

MySQL Group Replication（簡稱MGR）字面意思是mysql組復(fù)制的意思,但其實(shí)他是一個(gè)高可用的集群架構(gòu),暫時(shí)只支持mysql5.7和mysql8.0版本.

是MySQL官方于2016年12月推出的一個(gè)全新的高可用與高擴(kuò)展的解決方案,提供了高可用、高擴(kuò)展、高可靠的MySQL集群服務(wù).

也是mysql官方基于組復(fù)制概念并充分參考MariaDB Galera Cluster和Percona XtraDB Cluster結(jié)合而來的新的高可用集群架構(gòu).

MySQL Group Replication是建立在基于Paxos的XCom之上的，正因?yàn)橛辛薠Com基礎(chǔ)設(shè)施，保證數(shù)據(jù)庫狀態(tài)機(jī)在節(jié)點(diǎn)間的事務(wù)一致性，才能在理論和實(shí)踐中保證數(shù)據(jù)庫系統(tǒng)在不同節(jié)點(diǎn)間的事務(wù)一致性。

由一般主從復(fù)制概念擴(kuò)展,多個(gè)節(jié)點(diǎn)共同組成一個(gè)數(shù)據(jù)庫集群，事務(wù)的提交必須經(jīng)過半數(shù)以上節(jié)點(diǎn)同意方可提交,在集群中每個(gè)節(jié)點(diǎn)上都維護(hù)一個(gè)數(shù)據(jù)庫狀態(tài)機(jī)，保證節(jié)點(diǎn)間事務(wù)的一致性。

優(yōu)點(diǎn):

高一致性，基于原生復(fù)制及paxos協(xié)議的組復(fù)制技術(shù).

高容錯(cuò)性，有自動(dòng)檢測機(jī)制，當(dāng)出現(xiàn)宕機(jī)后,會(huì)自動(dòng)剔除問題節(jié)點(diǎn),其他節(jié)點(diǎn)可以正常使用(類似zk集群),當(dāng)不同節(jié)點(diǎn)產(chǎn)生資源爭用沖突時(shí),會(huì)按照先到先得處理,并且內(nèi)置了自動(dòng)化腦裂防護(hù)機(jī)制.

高擴(kuò)展性，可隨時(shí)在線新增和移除節(jié)點(diǎn),會(huì)自動(dòng)同步所有節(jié)點(diǎn)上狀態(tài)，直到新節(jié)點(diǎn)和其他節(jié)點(diǎn)保持一致，自動(dòng)維護(hù)新的組信息.

高靈活性，直接插件形式安裝(5.7.17后自帶.so插件),有單主模式和多主模式，單主模式下，只有主庫可以讀寫,其他從庫會(huì)加上super_read_only狀態(tài),只能讀取不可寫入,出現(xiàn)故障會(huì)自動(dòng)選主.

缺點(diǎn):

還是太新,不太穩(wěn)定,暫時(shí)性能還略差于PXC,對網(wǎng)絡(luò)穩(wěn)定性要求很高,至少是同機(jī)房做.

二、環(huán)境介紹

MySQL版本：8.0.15

數(shù)據(jù)庫端口：3306

集群復(fù)制端口：33006

MGR插件：group_replication.so

10.115.88.18：單主

10.115.88.19：從

10.115.88.20：從

三、安裝MySQL 8.0.15

3.1.1 下載地址：

https://cdn.mysql.com//Downloads/MySQL-8.0/mysql-8.0.15-linux-glibc2.12-x86_64.tar

3.1.2： 安裝數(shù)據(jù)庫

解壓

tar -xf mysql-8.0.15-linux-glibc2.12-x86_64.tar -C /home/work

進(jìn)入解壓目錄

cd /home/worktar xf mysql-8.0.15-linux-glibc2.12-x86_64.tar.gzmv mysql-8.0.15-linux-glibc2.12-x86_64 mysqlrm -rf *.xz

授予權(quán)限并創(chuàng)建數(shù)據(jù)目錄

cd /home/worktar xf mysql-8.0.15-linux-glibc2.12-x86_64.tar.gzmv mysql-8.0.15-linux-glibc2.12-x86_64 mysqlrm -rf *.xz chown -R work:work mysql mkdir data chown work:work data cd /home/work/mysql cd /home/work mkdir /home/work/relaylog chown -R work:work relaylog cd /home/work/mysql mkdir run chown -R work:work run

添加my.cnf文件

[client]default-character-set=utf8socket=/home/work/mysql/run/mysql.sock[mysqld]user = work port = 3306basedir=/home/work/mysqldatadir=/home/work/datasocket=/home/work/mysql/run/mysql.sockpid-file=/home/work/mysql/run/mysqld.pid# Disabling symbolic-links is recommended to prevent assorted security riskssymbolic-links=0lower_case_table_names = 1server-id = 183306 log-bin = mysql-binlog-bin-index = binlogs.indexbinlog_format = rowbinlog_rows_query_log_events = onbinlog_checksum = noneslave-parallel-type = LOGICAL_CLOCKslave-parallel-workers = 4slave_preserve_commit_order = 1#GITDgtid_mode = onenforce_gtid_consistency = 1log-slave-updates = 1binlog_gtid_simple_recovery = 1relay_log = /home/work/relaylog/relay.logrelay-log-index = /home/work/relaylog/relay.indexmaster_info_repository = tablerelay_log_info_repository = tableplugin_load='group_replication=group_replication.so'#MGR#GR配置項(xiàng) 基中l(wèi)oose前綴表示若group Replication plugin未加載 mysql server仍明治維新啟動(dòng)transaction_write_set_extraction = XXHASH64 #對每個(gè)事務(wù)獲取write set，并且用XXHASH64算法獲取hash值loose-group_replication_group_name = 'aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa' #組名，此處可拿select.uuid()生成loose-group_replication_start_on_boot = off #在mysqld啟動(dòng)時(shí)不自動(dòng)啟動(dòng)組復(fù)制loose-group_replication_local_address = '10.115.88.18:33006' #本節(jié)點(diǎn)的IP地址和端口，注意該端口是組內(nèi)成員之間通信的端口，而不是MySQL對外提供服務(wù)的端口loose-group_replication_group_seeds = '10.115.88.18:33006,10.115.88.19:33006,10.115.88.20:33006' #種子節(jié)點(diǎn)的IP和端口號(hào)，新成員加入到集群的時(shí)候需要聯(lián)系種子節(jié)點(diǎn)，啟動(dòng)集群的節(jié)點(diǎn)不使用該選項(xiàng)loose-group_replication_bootstrap_group = off #關(guān)閉，如果打開會(huì)造成腦裂 #是否啟動(dòng)集群，注意，該選項(xiàng)任何時(shí)候只能用于一個(gè)節(jié)點(diǎn)，通常情況下啟動(dòng)集群的時(shí)候使用，啟動(dòng)之后需要關(guān)閉該選項(xiàng)loose-group_replication_member_weight = 50 #權(quán)重選擇skip-host-cacheskip-name-resolveskip-external-lockingcharacter-set-server=utf8lower_case_table_names=1event_scheduler=onlog_bin_trust_function_creators=onmax_connections = 3000 external-locking = FALSE max_allowed_packet = 32M sort_buffer_size = 8M join_buffer_size = 2M thread_cache_size = 300 #query_cache_size = 64M #query_cache_limit = 4M read_rnd_buffer_size = 8Minnodb_buffer_pool_size = 8096Minnodb_log_file_size = 128Minnodb_log_files_in_group = 2innodb_log_buffer_size = 2Minnodb_flush_log_at_trx_commit = 1sync_binlog = 1[mysqld_safe]log-error=/home/work/data/err.log

初始化數(shù)據(jù)庫

bin/mysqld --initialize --basedir=/home/work/mysql --lower-case-table-names=1 --datadir=/home/work/data/ --user=work

拷貝啟動(dòng)文件

cp support-files/mysql.server /etc/init.d/mysqld

添加環(huán)境變量

echo ’export PATH=/home/work/mysql/bin:$PATH’ >>/etc/profilesource /etc/profile

數(shù)據(jù)庫啟動(dòng)

/etc/init.d/mysqld start

修改數(shù)據(jù)庫密碼

alter user’root’@’localhost’ IDENTIFIED BY ’dashuaige’; flush privileges;

四、配置MGR主

4.1.1 配置my.cnf文件

修改binlog如下：

server-id = 103306log-bin = mysql-binlog-bin-index = binlogs.indexbinlog_format = rowbinlog_rows_query_log_events = onbinlog_checksum = noneslave-parallel-type = LOGICAL_CLOCKslave-parallel-workers = 4slave_preserve_commit_order = 1

修改GTID如下：

gtid_mode = onenforce_gtid_consistency = 1log-slave-updates = 1binlog_gtid_simple_recovery = 1relay_log = /home/work/relaylog/relay.logrelay-log-index = /home/work/relaylog/relay.indexmaster_info_repository = tablerelay_log_info_repository = table

添加MGR插件

plugin_load='group_replication=group_replication.so'

修改MGR參數(shù)

#GR配置項(xiàng) 基中l(wèi)oose前綴表示若group Replication plugin未加載 mysql server仍明治維新啟動(dòng)transaction_write_set_extraction = XXHASH64 #對每個(gè)事務(wù)獲取write set，并且用XXHASH64算法獲取hash值loose-group_replication_group_name = 'aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa' #組名，此處可拿select.uuid()生成loose-group_replication_start_on_boot = off #在mysqld啟動(dòng)時(shí)不自動(dòng)啟動(dòng)組復(fù)制loose-group_replication_local_address = '10.115.88.18:33006' #本節(jié)點(diǎn)的IP地址和端口，注意該端口是組內(nèi)成員之間通信的端口，而不是MySQL對外提供服務(wù)的端口loose-group_replication_group_seeds = '10.115.88.18:33006,10.115.88.19:33006,10.115.88.20:33006' #種子節(jié)點(diǎn)的IP和端口號(hào)，新成員加入到集群的時(shí)候需要聯(lián)系種子節(jié)點(diǎn)，啟動(dòng)集群的節(jié)點(diǎn)不使用該選項(xiàng)loose-group_replication_bootstrap_group = off #關(guān)閉，如果打開會(huì)造成腦裂 #是否啟動(dòng)集群，注意，該選項(xiàng)任何時(shí)候只能用于一個(gè)節(jié)點(diǎn)，通常情況下啟動(dòng)集群的時(shí)候使用，啟動(dòng)之后需要關(guān)閉該選項(xiàng)loose-group_replication_member_weight = 50 #權(quán)重選擇

啟動(dòng)數(shù)據(jù)庫

/etc/init.d/mysqld restart

4.1.2 配置每臺(tái)hosts主機(jī)解析

[root@bj1-10-115-88-18 mysql]# cat /etc/hosts127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4::1 localhost localhost.localdomain localhost6 localhost6.localdomain610.115.88.18 bj1-10-115-88-1810.115.88.19 bj1-10-115-88-1910.115.88.20 bj1-10-115-88-20

4.1.3 配置mgr第一個(gè)主節(jié)點(diǎn)

以下步驟在10.115.88.18主機(jī)上的mysql中執(zhí)行

第一步：創(chuàng)建用于復(fù)制的用戶

set sql_log_bin=0;create user repuser@’%’ identified by ’repuser123’;grant replication slave,replication client on *.* to repuser@’%’;create user repuser@’127.0.0.1’ identified by ’repuser123’;grant replication slave,replication client on *.* to repuser@’127.0.0.1’;create user repuser@’localhost’ identified by ’repuser123’;grant replication slave,replication client on *.* to repuser@’localhost’;set sql_log_bin=1;

第二步：配置復(fù)制所使用的用戶

change master to master_user=’repuser’,master_password=’repuser123’ for channel ’group_replication_recovery’;

第三步：安裝mysql group replication這個(gè)插件

備注：如果在my.cnf里寫寫入plugin_load='group_replication=group_replication.so' 這步就可以不用操作install plugin group_replication soname ’group_replication.so’;通過show plugins;查看是否安裝成功

第四步：建個(gè)群(官方點(diǎn)的說法就是初始化一個(gè)復(fù)制組

set global group_replication_bootstrap_group=on;start group_replication;set global group_replication_bootstrap_group=off;select * from performance_schema.replication_group_members;

五、配置另外兩節(jié)點(diǎn)，從

以下步驟在所有從主機(jī)上的mysql中執(zhí)行

第一步：創(chuàng)建用于復(fù)制的用戶

set sql_log_bin=0;create user repuser@’%’ identified by ’repuser123’;grant replication slave,replication client on *.* to repuser@’%’;create user repuser@’127.0.0.1’ identified by ’repuser123’;grant replication slave,replication client on *.* to repuser@’127.0.0.1’;create user repuser@’localhost’ identified by ’repuser123’;grant replication slave,replication client on *.* to repuser@’localhost’;set sql_log_bin=1;

第二步：配置復(fù)制所使用的用戶

change master to master_user=’repuser’,master_password=’repuser123’ for channel ’group_replication_recovery’;

第三步：安裝mysql group replication這個(gè)插件

備注：如果在my.cnf里寫寫入plugin_load='group_replication=group_replication.so' 這步就可以不用操作install plugin group_replication soname ’group_replication.so’;通過show plugins;查看是否安裝成功

第四步：加入前面創(chuàng)建好的復(fù)制組

start group_replication;select * from performance_schema.replication_group_members;

如下出現(xiàn)以下報(bào)錯(cuò)

這是binlog導(dǎo)致的錯(cuò)誤，執(zhí)行以下

reset master;start group_replication;select * from performance_schema.replication_group_members;

查看是MGR狀態(tài)：

查看MGR主的讀寫狀態(tài)

查看MGR兩臺(tái)從的讀寫狀態(tài)

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