一些名詞介紹：

    WS：write set 寫資料集
    IST: Incremental State Transfer 增量同步
    SST：State Snapshot Transfer 全量同步 

pxc環境所涉及的埠：

    #mysql例項埠

   1. Regular MySQL port, default 3306.   

   #pxc cluster相互通訊的埠
   2. Port for group communication, default 4567. It can be changed by the option:  
       wsrep_provider_options ="gmcast.listen_addr=tcp://0.0.0.0:4010; "

   #用於SST傳送的埠
   3. Port for State Transfer, default 4444. It can be changed by the option: 
       wsrep_sst_receive_address=10.11.12.205:5555

   #用於IST傳送的埠
   4. Port for Incremental State Transfer, default port for group communication + 1 (4568). It can be changed by the option: 
       wsrep_provider_options = "ist.recv_addr=10.11.12.206:7777; "

搭建步驟：

一、環境情況：

     node1:192.168.1.81:6000

     node2:192.168.1.240:6000

     node3:192.168.1.241:6000

二、防火牆設定：

-A INPUT -m state --state NEW -m tcp -p tcp --dport 3306 -j ACCEPT #本實驗需要改為6000
-A INPUT -m state --state NEW -m tcp -p tcp --dport 4444 -j ACCEPT #本實驗需要改為6020
-A INPUT -m state --state NEW -m tcp -p tcp --dport 4567 -j ACCEPT #本實驗需要改為6030
-A INPUT -m state --state NEW -m tcp -p tcp --dport 4568 -j ACCEPT #本實驗需要改為6031

setenforce 0

二、下載安裝，在node1,node2,node3分別進行如下安裝

yum install -y  http://www.percona.com/downloads/percona-release/redhat/0.1-3/percona-release-0.1-3.noarch.rpm
yum install -y perl-DBD-MySQL.x86_64 perl-IO-Socket-SSL.noarch socat.x86_64 nc
yum install -y  openssl openssl-devel

#step 1 prepare :5.6.26 needs libssl.so.6 libcrypto.so.6 ()
cd /usr/lib64
ln -s libssl.so.1.0.1e libssl.so.6
ln -s  libcrypto.so.1.0.1e libcrypto.so.6

#step2:download pxc
cd /usr/local/src
wget https://www.percona.com/downloads/Percona-XtraDB-Cluster-56/Percona-XtraDB-Cluster-5.6.26-25.12/binary/tarball/Percona-XtraDB-Cluster-5.6.26-rel74.0-25.12.1.Linux.x86_64.tar.gz
cd /usr/local
mv Percona-XtraDB-Cluster-5.6.26-rel74.0-25.12.1.Linux.x86_64.tar.gz pxc_56

#step3:install pxc
cd /usr/local/pxc_56
 ./scripts/mysql_install_db --defaults-file=/home/mysql/my6000.cnf --basedir=/usr/local/pxc_56

  chown -R mysql. /home/mysql

  chown -R mysql. /usr/local/pxc_56

 配置檔案：my6000.cnf

[client]
port            = 6000
socket          = /home/mysql/I6000/mysql.sock
default-character-set=utf8

[mysqld]
basedir = /usr/local/pxc_56
datadir = /home/mysql/I6000

pid-file        = /home/mysql/I6000/mysql.pid
character-set-server=utf8
init_connect = 'SET NAMES utf8'
log-bin=/home/mysql/I6000/log_bin
server-id = 9816000

innodb_buffer_pool_size = 100M
innodb_data_file_path = ibdata1:10M:autoextend
innodb_data_home_dir = /home/mysql/I6000
innodb_file_per_table=1


skip-name-resolve


port            = 6000
socket          = /home/mysql/I6000/mysql.sock
user=mysql
log_error=/home/mysql/I6000/mysql_error.log

#pxc
user=mysql
log_error=error.log
binlog_format=ROW

#6000 for mysqld port, 6020 for sst port, 6031 for ist port, 6030 for cluster communication port 埠作用及說明見上面
wsrep_cluster_address='gcomm://192.168.1.81:6030,192.168.1.238:6030,192.168.1.240:6030' #三個節點都保持一樣
wsrep_provider=/usr/local/pxc_56/lib/libgalera_smm.so
wsrep_sst_receive_address=192.168.1.238:6020  #根據不同的node ip進行修改
wsrep_node_incoming_address=192.168.1.238:6000  #根據不同的node ip進行修改
wsrep_node_address=192.168.1.238:6000  #根據不同的node ip進行修改
wsrep_provider_options = "gmcast.listen_addr=tcp://192.168.1.238:6030;ist.recv_addr=192.168.1.238:6031;"  #根據不同的node ip進行修改

wsrep_slave_threads=2
wsrep_cluster_name=pxc_zejin   #同一個cluster此值需要一致
wsrep_sst_method=xtrabackup-v2
wsrep_node_name=node6000_238  #不同節點修改為不同的名字
innodb_autoinc_lock_mode=2
wsrep_sst_auth="sstuser:123"
log-slave-updates


[mysql]
no-auto-rehash
default-character-set=utf8

 三、例項啟動：

#安裝例項
/usr/local/pxc_56/scripts/mysql_install_db --defaults-file=/home/mysql/my6000.cnf --basedir=/usr/local/pxc_56
#啟動第一個例項
/usr/local/pxc_56/bin/mysqld_safe --defaults-file=/home/mysql/my6000.cnf --ledir=/usr/local/pxc_56/bin/ --wsrep-new-cluster  & 
#修改密碼
/usr/local/pxc_56/bin/mysqladmin -u root -P6000 password '000000' -S /home/mysql/I6000/mysql.sock
#登陸並增加使用者
/usr/local/pxc_56/bin/mysql -uroot -p -P6000 -S /home/mysql/I6000/mysql.sock 
grant all on *.* to 'sstuser'@'localhost' identified by '123';
flush privielges;

mysql> show global status like 'wsrep_cluster_size';
+--------------------+-------+
| Variable_name      | Value |
+--------------------+-------+
| wsrep_cluster_size | 1     |
+--------------------+-------+
1 row in set (0.00 sec)

四、啟動第二、三個node

#不需要加--wsrep-new-cluster
/usr/local/pxc_56/bin/mysqld_safe --defaults-file=/home/mysql/I6000/my6000.cnf --ledir=/usr/local/pxc_56/bin/ & 

整個過程大約如下：

   1.決斷是否可以IST

   2.不可以的話Requesting state transfer

   3.Cleaning the existing datadir and innodb-data/log directories 會將之前例項的內容全部刪除。#所以不能將my6000.cnf檔案放在與datadir目錄下，要不會被刪除，並且在重新啟動服務時出錯

   4.Waiting for SST streaming to complete

   5.啟動服務。

  官方說明：

    XtraBackup SST works in two stages:
      • Stage I on joiner checks if it is SST or IST based on presence of xtrabackup_ist file.
      • In Stage II it starts the data transfer, if it’s SST, it empties the data directory sans few files (galera.cache, sst_in_progress, grastate.dat) and then proceed with the SST or if it’s IST, proceeds as before.

加入成功：
07:49:13 [email protected]:[test] 6000>show global status like 'wsrep_cluster_size';
+--------------------+-------+
| Variable_name      | Value |
+--------------------+-------+
| wsrep_cluster_size | 3     |
+--------------------+-------+
1 row in set (0.00 sec)

五、操作過程中經常用到的命令：

安裝：/usr/local/pxc_56/scripts/mysql_install_db --defaults-file=/home/mysql/my6000.cnf --basedir=/usr/local/pxc_56
啟動：/usr/local/pxc_56/bin/mysqld_safe --defaults-file=/home/mysql/my6000.cnf --ledir=/usr/local/pxc_56/bin/ &  ( 第一個節點要加上--wsrep-new-cluster )
登陸：/usr/local/pxc_56/bin/mysql -uroot -p -P6000 -S /home/mysql/I6000/mysql.sock 
關閉：/usr/local/pxc_56/bin/mysqladmin -uroot -p -P6000 -S /home/mysql/I6000/mysql.sock  shutdown

六、安裝過程中可能遇到的問題：

A.

節點啟動時：
/usr/local/pxc_56/bin/mysqld_safe --defaults-file=/home/mysql/my3307.cnf --ledir=/usr/local/pxc_56/bin/ &
有可能啟動會提示：
WSREP_SST: [ERROR] socat not found in path: /usr/sbin:/sbin:/usr/local/pxc_56//bin:/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/opt/lamp/mysql/bin:/root/bi
n (20160509 10:58:04.404)
2016-05-09 10:58:04 54809 [ERROR] WSREP: Failed to read 'ready <addr>' from: wsrep_sst_xtrabackup-v2 --role 'joiner' --address '192.168.1.238' --datadir '/home/mysql/I3307/
' --defaults-file '/home/mysql/I3307/my3307.cnf' --defaults-group-suffix '' --parent '54809'  '' 
        Read: '(null)'
2016-05-09 10:58:04 54809 [ERROR] WSREP: Process completed with error: wsrep_sst_xtrabackup-v2 --role 'joiner' --address '192.168.1.238' --datadir '/home/mysql/I3307/' --de
faults-file '/home/mysql/I3307/my3307.cnf' --defaults-group-suffix '' --parent '54809'  '' : 2 (No such file or directory)
2016-05-09 10:58:04 54809 [ERROR] WSREP: Failed to prepare for 'xtrabackup-v2' SST. Unrecoverable.
2016-05-09 10:58:04 54809 [ERROR] Aborting

原因及解決方法：socat 沒有安裝到，之前源包沒有，可以進行如下安裝：

yum install socat

B.

第一個節點如果直接這樣啟動：
/usr/local/pxc_56/bin/mysqld_safe --defaults-file=/home/mysql/my6000.cnf &

在errorlog裡面會出現：
2016-05-09 09:49:46 9932 [ERROR] WSREP: failed to open gcomm backend connection: 110: failed to reach primary view: 110 (Connection timed out)
         at gcomm/src/pc.cpp:connect():162
2016-05-09 09:49:46 9932 [ERROR] WSREP: gcs/src/gcs_core.cpp:gcs_core_open():206: Failed to open backend connection: -110 (Connection timed out)
2016-05-09 09:49:46 9932 [ERROR] WSREP: gcs/src/gcs.cpp:gcs_open():1379: Failed to open channel 'pxc_zejin' at 'gcomm://192.168.1.240,192.168.1.238,192.168.1.81': -110 (Con
nection timed out)
2016-05-09 09:49:46 9932 [ERROR] WSREP: gcs connect failed: Connection timed out
2016-05-09 09:49:46 9932 [ERROR] WSREP: wsrep::connect(gcomm://192.168.1.240,192.168.1.238,192.168.1.81) failed: 7
2016-05-09 09:49:46 9932 [ERROR] Aborting

2016-05-09 09:49:46 9932 [Note] WSREP: Service disconnected.
2016-05-09 09:49:47 9932 [Note] WSREP: Some threads may fail to exit.
2016-05-09 09:49:47 9932 [Note] Binlog end
2016-05-09 09:49:47 9932 [Note] /usr/local/pxc_56/bin/mysqld: Shutdown complete

解決方法：第一個節點啟動要加上：--wsrep-new-cluster

 /usr/local/pxc_56/bin/mysqld_safe --defaults-file=/home/mysql/my6000.cnf --ledir=/usr/local/pxc_56/bin --wsrep-new-cluster  &

 C.

#第二個節點或第三個節點啟動報錯：
WSREP_SST: [ERROR] Cleanup after exit with status:1 (20160509 19:25:50.483)
2016-05-09 19:25:50 44334 [ERROR] WSREP: Process completed with error: wsrep_sst_xtrabackup-v2 --role 'joiner' --address '192.168.1.240:6020' --datadir '/home/mysql/I6000/'
 --defaults-file '/home/mysql/I6000/my6000.cnf' --defaults-group-suffix '' --parent '44334'  '' : 1 (Operation not permitted)
2016-05-09 19:25:50 44334 [ERROR] WSREP: Failed to read uuid:seqno from joiner script.
2016-05-09 19:25:50 44334 [ERROR] WSREP: SST script aborted with error 1 (Operation not permitted)
2016-05-09 19:25:50 44334 [ERROR] WSREP: SST failed: 1 (Operation not permitted)
2016-05-09 19:25:50 44334 [ERROR] Aborting

原因及解決方法：配置檔案my6000.cnf放在與datadir目錄下，在Cleaning the existing datadir階段被刪除，在重啟服務時就會找不到配置檔案，在重新啟動服務就會出錯，把配置檔案放在非datadir目錄下即可。如/etc/my6000.cnf