為什么80%的碼農都做不了架構師？>>> ??

聽說很多大公司都在使用mysql ha(mysql-master-ha)的環境,下面，我也試著搭建測試一下。 一.MHA原理及其特點： 1.原理： MHA在主服務器發生故障時，自動實現故障轉移，快速將從服務器晉級為主服務器(通常在10-30s)，而不影響復制的一致性，適用于任何存儲引擎 MHA 提供在線服務器切換，將從服務器器提升為主服務器，時間在0.5-2s，這段時間，數據是無法寫入的。 MHA manager 是通過ssh 連接到 mysql slave服務器上 MHA 每次從宕掉的主服務器上保存二進制日志，但不是每次都成功(主服務器硬件故障或無法通過ssh訪問) mysql 5.5支持半同步復制，MHA與半同步復制結合，可以大大降低數據丟失的風險， 2.特性： (1).主服務器的自動監控和故障轉移 (2).交互式主服務器故障遷移(使用MHA實現故障遷移，不監控主服務器，出現故障，手工調用MHA切換) (3).非交互式的主故障遷移(不監控主服務器，但自動實現故障轉移) (4).在線切換主服務器 注： MHA 可以應用于任何復制結構(此點待定) 二.MHA的前提條件： 1.搭建的前提條件： (1).mysql 主從復制已配置好(master-slave) (2).4臺server 設置SSH公鑰免密碼登錄 (3).操作系統為linux系統(MHA 只支持linux系統) (4).單臺可寫主服務器和多臺從服務器或只讀服務器 (5).mysql 版本為5.0或以上版本 (6).候選主服務器的log-bin必須開啟 (7). 所有服務器上的二進制日志和中級日志過濾規則必須相同 (8).候選服務器上的復制用戶必須存在 (9). 保留中繼日志和定期清理 參考文章：http://www.vmcd.org/2012/04/mysql-high-availability-mha/ 2.MHA的基本說明： MHA由node 和 manage 組成， node 安裝在每一臺mysql服務器上(主從上都要裝)， manage端運行在獨立服務器上，也需要安裝node節點 3.MHA 切換過程： (1).監控和故障轉移過程 檢測復制設置和確定當前主服務器 監控主服務器 檢測主服務器當掉 再次檢測從服務器配置 關閉當掉的主服務器(可選) 恢復一個新的主服務器 激活新的主服務器 恢復其余的從服務器 告警(可選) (2).在線切換過程 檢測復制設置和確定當前主服務器 確定新的主服務器 阻塞寫入到當前主服務器 等待所有從服務器趕上復制 授予寫入到新的主服務器 重新設置從服務器 三.MHA 部署實例： 主DB：192.168.1.101 從DB1：192.168.1.102 從DB2：192.168.1.103 MHA管理端：192.168.1.100 系統版本：red hat linux 6 數據庫版本：mysql 5.5 注：默認mysql主從配置已經配置完畢

1.對mysql的主從進行半同步配置、從上建立復制的用戶和授予相應的權限、日志清除設置

#?所有mysql數據庫服務器，安裝半同步插件(semisync_master.so,semisync_slave.so)??

mysql>?install?plugin?rpl_semi_sync_master?soname?'semisync_master.so';??????

mysql>?install?plugin?rpl_semi_sync_slave?soname?'semisync_slave.so';??

#?注：其實master是安裝在主，slave是安裝在從上，但是我們是涉及從升級為主，所以主從都裝??

#?卸載插件使用命令：???

#?mysql>?uninstall?plugin?rpl_semi_sync_slave;??

#?mysql>?uninstall?plugin?rpl_semi_sync_master;??

#?修改所有數據庫服務器的參數文件(/etc/my.cnf)，添加內容如下：??

[root@client101-103??~]#?vim?/etc/my.cnf??

rpl_semi_sync_master_enabled=1??

rpl_semi_sync_master_timeout=1000??

rpl_semi_sync_slave_enabled=1??

relay_log_purge=0?????#?此參數將定期清除中繼日志功能關閉??

#?重啟數據庫，查看同步狀態和半同步參數、狀態??

[root@client101-103??~]#?/etc/init.d/mysql?restart??

#?查看半同步參數：??

mysql>?show?variables?like?'%sync%';??

#?查看半同步狀態：??

mysql>?show?status?like?'%sync%';??

#?有幾個狀態參數值得關注的：??

rpl_semi_sync_master_status：顯示主服務是異步復制模式還是半同步復制模式??

rpl_semi_sync_master_clients：顯示有多少個從服務器配置為半同步復制模式??

rpl_semi_sync_master_yes_tx：顯示從服務器確認成功提交的數量??

rpl_semi_sync_master_no_tx：顯示從服務器確認不成功提交的數量??

rpl_semi_sync_master_tx_avg_wait_time：事務因開啟semi_sync，平均需要額外等待的時間??

rpl_semi_sync_master_net_avg_wait_time：事務進入等待隊列后，到網絡平均等待時間??

#?兩臺從數據庫建立用于復制的用戶和密碼??

mysql>?GRANT?REPLICATION?SLAVE?ON?*.*?TO?'slave'@'192.168.1.%'?IDENTIFIED?BY?'slave';??

mysql>?flush?privileges;??

2.4臺server建立ssh無密碼驗證登陸

注：ssh-keygen??-t???rsa：??

#?manage?端??

[root@client100?~]#?ssh-keygen??-t?rsa??

[root@client100?~]#?ssh-copy-id?root@192.168.1.101??

[root@client100?~]#?ssh-copy-id?root@192.168.1.102??

[root@client100?~]#?ssh-copy-id?root@192.168.1.103??

#?主DB???

[root@client101?~]#?ssh-keygen??-t?rsa??

[root@client101?~]#?ssh-copy-id?root@192.168.1.100??

[root@client101?~]#?ssh-copy-id?root@192.168.1.102??

[root@client101?~]#?ssh-copy-id?root@192.168.1.103??

#?從DB1???

[root@client102?~]#?ssh-keygen??-t?rsa??

[root@client102?~]#?ssh-copy-id?root@192.168.1.100??

[root@client102?~]#?ssh-copy-id?root@192.168.1.102??

[root@client102?~]#?ssh-copy-id?root@192.168.1.103??

#?從DB2???

[root@client103?~]#?ssh-keygen??-t?rsa??

[root@client103?~]#?ssh-copy-id?root@192.168.1.100??

[root@client103?~]#?ssh-copy-id?root@192.168.1.101??

[root@client103?~]#?ssh-copy-id?root@192.168.1.102??

3.在3臺數據庫節點安裝MHA的node節點：

#?如果安裝下面包，報依賴關系錯，請先安裝mysql-share-compat包??

#?先安裝下面的?perl-dbd-mysql包??

#?在下面執行perl時，如果出現報錯，需要安裝如下這幾個perl包：?perl-devel?perl-CPAN??

##?在192.168.1.101上執行如下操作??

[root@client101?~]#?yum?-y?install?perl-DBD-MySQL??

[root@client101?~]#?tar?-xf?mha4mysql-node-0.54.tar.gz??

[root@client101?~]#?cd?mha4mysql-node-0.54??

[root@client101?mha4mysql-node-0.54]#?perl?Makefile.PL??

[root@client101?mha4mysql-node-0.54]#?make?&&?make?install??

#?在192.168.1.102上執行如下操作??

[root@client102?~]#?yum?-y?install?perl-DBD-MySQL??

[root@client102?~]#?tar?-xf?mha4mysql-node-0.54.tar.gz??

[root@client102?~]#?cd?mha4mysql-node-0.54??

[root@client102?mha4mysql-node-0.54]#?perl?Makefile.PL??

[root@client102?mha4mysql-node-0.54]#?make?&&?make?install??

#?在192.168.1.103上執行如下操作??

[root@client103?~]#?yum?-y?install?perl-DBD-MySQL??

[root@client103?~]#?tar?-xf?mha4mysql-node-0.54.tar.gz??

[root@client103?~]#?cd?mha4mysql-node-0.54??

[root@client103?mha4mysql-node-0.54]#?perl?Makefile.PL??

[root@client103?mha4mysql-node-0.54]#?make?&&?make?install??

4.管理節點安裝MHA的manager和node(192.168.1.100):

#?管理節點一定記得裝mha4mysql-node-0.54.tar.gz??和??mha4mysql-manager-0.55.tar.gz???

#?管理節點，不裝node?會報錯的??

#?安裝相關perl包(有些包，系統沒有自帶，需要自行下載安裝)??

[root@client100?~]#?yum?install?perl-DBD-MySQL?perl-Config-Tiny?perl-Log-Dispatch?perl-Parallel-ForkManager?perl-Config-IniFiles??

[root@client100?~]#?tar?-xf?mha4mysql-node-0.54.tar.gz??

[root@client100?~]#?cd?mha4mysql-node-0.54??

[root@client100?mha4mysql-node-0.54]#?perl?Makefile.PL??

[root@client100?mha4mysql-node-0.54]#?make?&&?make?install??

??

[root@client100?~]#?tar?-xf?mha4mysql-manager-0.55.tar.gz??

[root@client100?~]#?cd?mha4mysql-manager-0.55??

[root@client100?mha4mysql-manager-0.55]#?perl?Makefile.PL??

[root@client100?mha4mysql-manager-0.55]#?make?&&?make?install??

5.編輯管理節點的配置文件

#?建立配置文件存放目錄，并將模板配置文件復制到新建目錄??

[root@client100?~]#?mkdir?/etc/mastermha??

[root@client100?~]#?mkdir?-p?/mastermha/app1??

[root@client100?~]#?cd?/tmp/mha4mysql-manager-0.55??

[root@client100?mha4mysql-manager-0.55]#?cp?samples/conf/*?/etc/mastermha/??

[root@client100?~]#?vim?/etc/mastermha/app1.cnf??

[server?default]??

manager_workdir=/masterha/app1??

manager_log=/masterha/app1/manager.log??

user=mha_mon??

password=123456??

ssh_user=root??

repl_user=slave??

repl_password=slave??

ping_interval=1??

shutdown_script=""??

master_ip_online_change_script=""??

report_script=""??

??

[server1]??

hostname=192.168.1.101??

master_binlog_dir=/var/lib/mysql/??

candidate_master=1??

??

[server2]??

hostname=192.168.1.102??

master_binlog_dir=/var/lib/mysql??

candidate_master=1??

??

[server3]??

hostname=192.168.1.103??

#master_binlog_dir=/var/lib/mysql??

no_master=1???

6.在所有數據庫節點的機器上進行授權操作(192.168.1.101/192.168.1.102/192.168.1.103)

mysql>?grant?all?privileges?on?*.*?to?'mha_mon'@'192.168.1.%'?identified?by?'123456';??

Query?OK,?0?rows?affected?(1.00?sec)??

mysql>?flush?privileges;??

7.測試ssh連接是否正常

#?所有都為ok?即為正常??

[root@client100?mastermha]#?masterha_check_ssh??--global_conf=/etc/mastermha/masterha_default.cnf??--conf=/etc/mastermha/app1.cnf??

Sun?Mar??2?14:52:53?2014?-?[info]?Reading?default?configuratoins?from?/etc/mastermha/masterha_default.cnf..??

Sun?Mar??2?14:52:53?2014?-?[info]?Reading?application?default?configurations?from?/etc/mastermha/app1.cnf..??

Sun?Mar??2?14:52:53?2014?-?[info]?Reading?server?configurations?from?/etc/mastermha/app1.cnf..??

Sun?Mar??2?14:52:53?2014?-?[info]?Starting?SSH?connection?tests..??

Sun?Mar??2?14:53:04?2014?-?[debug]??

Sun?Mar??2?14:52:53?2014?-?[debug]??Connecting?via?SSH?from?root@192.168.1.102(192.168.1.102:22)?to?root@192.168.1.101(192.168.1.101:22)..??

Sun?Mar??2?14:53:03?2014?-?[debug]???ok.??

Sun?Mar??2?14:53:03?2014?-?[debug]??Connecting?via?SSH?from?root@192.168.1.102(192.168.1.102:22)?to?root@192.168.1.103(192.168.1.103:22)..??

Sun?Mar??2?14:53:04?2014?-?[debug]???ok.??

Sun?Mar??2?14:53:04?2014?-?[debug]??

Sun?Mar??2?14:52:54?2014?-?[debug]??Connecting?via?SSH?from?root@192.168.1.103(192.168.1.103:22)?to?root@192.168.1.101(192.168.1.101:22)..??

Sun?Mar??2?14:53:04?2014?-?[debug]???ok.??

Sun?Mar??2?14:53:04?2014?-?[debug]??Connecting?via?SSH?from?root@192.168.1.103(192.168.1.103:22)?to?root@192.168.1.102(192.168.1.102:22)..??

Sun?Mar??2?14:53:04?2014?-?[debug]???ok.??

Sun?Mar??2?14:54:53?2014?-?[debug]??

Sun?Mar??2?14:52:53?2014?-?[debug]??Connecting?via?SSH?from?root@192.168.1.101(192.168.1.101:22)?to?root@192.168.1.102(192.168.1.102:22)..??

Sun?Mar??2?14:53:53?2014?-?[debug]???ok.??

Sun?Mar??2?14:53:53?2014?-?[debug]??Connecting?via?SSH?from?root@192.168.1.101(192.168.1.101:22)?to?root@192.168.1.103(192.168.1.103:22)..??

Sun?Mar??2?14:54:53?2014?-?[debug]???ok.??

Sun?Mar??2?14:54:53?2014?-?[info]?All?SSH?connection?tests?passed?successfully.??

8.測試數據庫之間的復制情況：

#?如果正常點額話，下面會有ok顯示??

[root@client100?mastermha]#?masterha_check_repl?--global_conf=/etc/mastermha/masterha_default.cnf??--conf=/etc/mastermha/app1.cnf??

Sun?Mar??2?15:10:16?2014?-?[info]?Reading?default?configuratoins?from?/etc/mastermha/masterha_default.cnf..??

Sun?Mar??2?15:10:16?2014?-?[info]?Reading?application?default?configurations?from?/etc/mastermha/app1.cnf..??

Sun?Mar??2?15:10:16?2014?-?[info]?Reading?server?configurations?from?/etc/mastermha/app1.cnf..??

Sun?Mar??2?15:10:16?2014?-?[info]?MHA::MasterMonitor?version?0.55.??

Sun?Mar??2?15:10:25?2014?-?[info]?Dead?Servers:??

Sun?Mar??2?15:10:25?2014?-?[info]???192.168.1.101(192.168.1.101:3306)??

Sun?Mar??2?15:10:25?2014?-?[info]?Alive?Servers:??

Sun?Mar??2?15:10:25?2014?-?[info]???192.168.1.102(192.168.1.102:3306)??

Sun?Mar??2?15:10:25?2014?-?[info]???192.168.1.103(192.168.1.103:3306)??

Sun?Mar??2?15:10:25?2014?-?[info]?Alive?Slaves:??

Sun?Mar??2?15:10:25?2014?-?[info]???192.168.1.102(192.168.1.102:3306)??Version=5.5.36-log?(oldest?major?version?between?slaves)?log-bin:enabled??

Sun?Mar??2?15:10:25?2014?-?[info]?????Replicating?from?192.168.1.101(192.168.1.101:3306)??

Sun?Mar??2?15:10:25?2014?-?[info]?????Primary?candidate?for?the?new?Master?(candidate_master?is?set)??

Sun?Mar??2?15:10:25?2014?-?[info]???192.168.1.103(192.168.1.103:3306)??Version=5.5.36-log?(oldest?major?version?between?slaves)?log-bin:enabled??

Sun?Mar??2?15:10:25?2014?-?[info]?????Replicating?from?192.168.1.101(192.168.1.101:3306)??

Sun?Mar??2?15:10:25?2014?-?[warning]?MySQL?master?is?not?currently?alive!??

Sun?Mar??2?15:10:25?2014?-?[info]?Checking?slave?configurations..??

Sun?Mar??2?15:10:25?2014?-?[info]??read_only=1?is?not?set?on?slave?192.168.1.102(192.168.1.102:3306).??

Sun?Mar??2?15:10:25?2014?-?[warning]??relay_log_purge=0?is?not?set?on?slave?192.168.1.102(192.168.1.102:3306).??

Sun?Mar??2?15:10:25?2014?-?[info]?Checking?replication?filtering?settings..??

Sun?Mar??2?15:10:25?2014?-?[info]??Replication?filtering?check?ok.??

Sun?Mar??2?15:10:25?2014?-?[info]?Starting?SSH?connection?tests..??

Sun?Mar??2?15:10:26?2014?-?[info]?All?SSH?connection?tests?passed?successfully.??

Sun?Mar??2?15:10:26?2014?-?[info]?Checking?MHA?Node?version..??

Sun?Mar??2?15:10:26?2014?-?[info]??Version?check?ok.??

Sun?Mar??2?15:10:26?2014?-?[info]?Getting?current?master?(maybe?dead)?info?..??

Sun?Mar??2?15:10:26?2014?-?[info]?Identified?master?is?192.168.1.101(192.168.1.101:3306).??

Sun?Mar??2?15:10:26?2014?-?[info]?Checking?SSH?publickey?authentication?settings?on?the?current?master..??

Sun?Mar??2?15:10:31?2014?-?[warning]?HealthCheck:?Got?timeout?on?checking?SSH?connection?to?192.168.1.101!?at?/usr/local/share/perl5/MHA/HealthCheck.pm?line?298.??

Sun?Mar??2?15:10:31?2014?-?[info]?Checking?SSH?publickey?authentication?and?checking?recovery?script?configurations?on?all?alive?slave?servers..??

Sun?Mar??2?15:10:31?2014?-?[info]???Executing?command?:?apply_diff_relay_logs?--command=test?--slave_user='mha_mon'?--slave_host=192.168.1.102?--slave_ip=192.168.1.102?--slave_port=3306?--workdir=/data/log/masterha?--target_version=5.5.36-log?--manager_version=0.55?--relay_log_info=/var/lib/mysql/relay-log.info??--relay_dir=/var/lib/mysql/??--slave_pass=xxx??

Sun?Mar??2?15:10:31?2014?-?[info]???Connecting?to?root@192.168.1.102(192.168.1.102:22)..??

Creating?directory?/data/log/masterha..?done.??

??Checking?slave?recovery?environment?settings..??

????Opening?/var/lib/mysql/relay-log.info?...?ok.??

????Relay?log?found?at?/var/lib/mysql,?up?to?mysql-relay-bin.000007??

????Temporary?relay?log?file?is?/var/lib/mysql/mysql-relay-bin.000007??

????Testing?mysql?connection?and?privileges..?done.??

????Testing?mysqlbinlog?output..?done.??

????Cleaning?up?test?file(s)..?done.??

Sun?Mar??2?15:10:31?2014?-?[info]???Executing?command?:?apply_diff_relay_logs?--command=test?--slave_user='mha_mon'?--slave_host=192.168.1.103?--slave_ip=192.168.1.103?--slave_port=3306?--workdir=/data/log/masterha?--target_version=5.5.36-log?--manager_version=0.55?--relay_log_info=/var/lib/mysql/relay-log.info??--relay_dir=/var/lib/mysql/??--slave_pass=xxx??

Sun?Mar??2?15:10:31?2014?-?[info]???Connecting?to?root@192.168.1.103(192.168.1.103:22)..??

Creating?directory?/data/log/masterha..?done.??

??Checking?slave?recovery?environment?settings..??

????Opening?/var/lib/mysql/relay-log.info?...?ok.??

????Relay?log?found?at?/var/lib/mysql,?up?to?mysql-relay-bin.000009??

????Temporary?relay?log?file?is?/var/lib/mysql/mysql-relay-bin.000009??

????Testing?mysql?connection?and?privileges..?done.??

????Testing?mysqlbinlog?output..?done.??

????Cleaning?up?test?file(s)..?done.??

Sun?Mar??2?15:10:32?2014?-?[info]?Slaves?settings?check?done.??

Sun?Mar??2?15:10:32?2014?-?[info]??

192.168.1.101?(current?master)??

+--192.168.1.102??

+--192.168.1.103??

??

Sun?Mar??2?15:10:32?2014?-?[info]?Checking?replication?health?on?192.168.1.102..??

Sun?Mar??2?15:10:32?2014?-?[info]??ok.??

Sun?Mar??2?15:10:32?2014?-?[info]?Checking?replication?health?on?192.168.1.103..??

Sun?Mar??2?15:10:32?2014?-?[info]??ok.??

Sun?Mar??2?15:10:32?2014?-?[warning]?master_ip_failover_script?is?not?defined.??

Sun?Mar??2?15:10:32?2014?-?[warning]?shutdown_script?is?not?defined.??

Sun?Mar??2?15:10:32?2014?-?[info]?Got?exit?code?0?(Not?master?dead).??

??

MySQL?Replication?Health?is?OK.??

9.啟動管理節點進程：

[root@client100?mastermha]#nohup?masterha_manager?--conf=/etc/mastermha/app1.cnf?>?/tmp/mha_manager.log??</dev/null?2>&1?&??

#?可以用以下命令，查看mha?進程是否啟動??

[root@client100?mastermha]#?ps?-ef?|grep?mha???

#?檢查MHA狀態：??

[root@client100?~]#?masterha_check_status??--global_conf=/etc/mastermha/masterha_default.cnf??--conf=/etc/mastermha/app1.cnf??

?app1?(pid:2835)?is?running(0:PING_OK),?master:192.168.1.101??

#??正常情況下，如果為ok，則mha已經配置成功??

#?也可以查看相關日志，/masterha/app1/manager.log?此日記記錄詳細切換過程??

10.測試：

關閉目前為主的mysql，仔細查看日志，系統會自動進行切換 注：切換失敗后，再次啟動管理端，是啟不來的，需要刪除目錄下相關app1.failover.complete，才可正常開啟 各位自行測試，有問題，可以互相探討。

轉載于:https://my.oschina.net/liting/blog/403969

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