1. 下載安裝包

移步這里下載：https://download.csdn.net/download/fm0517/10577703

2. 節點分類及說明

【GTM】
全局事務控制節點，保證集群數據的一致性，與Coordinator節點和Datanode節點不斷通信，是整個集群的核心節點，只存在一個，可以存在一個GTM Standby節點，對GTM實時備份。GTM一旦故障，整個集群立刻無法訪問，此時可以切換到GTM Standby節點上。如果部署了GTM Standby節點，就應該同時部署GTM Proxy，一般和Coordinator、Datanode部署在同一臺服務器上。GTM Proxy的作用代理Coordinator和Datanode對GTM的訪問，起到減輕GTM負載的作用，另外一個重要的作用是幫助完成GTM的故障切換，當GTM節點發生故障后，GTM Standby成為新的GTM，此時Coordinator和Datanode節點并不需要重新指定GTM地址，只需要GTM Proxy重新連接到新的GTM地址即可。

【Coordinator】
接收數據訪問請求的節點，本質上是由PG后臺進程組成。接收的一條查詢后，Coordinator節點執行查詢計劃，然后會根據查詢數據涉及的數據節點將查詢分發給相關的數據節點。寫入數據時，也會根據不同的數據分布策略將數據寫入相關的節點。可以說Coordinator節點上保存著集群的全局數據位置。Coordinator節點可以任意擴展，各個節點之間除了訪問地址不同以外是完全對等的，通過一個節點更新的數據可以在另一個節點上立刻看到。每個Coordinator節點可以配置一個對應的standby節點，避免單點故障。

【Datanode】
實際存取數據的節點，接收Coordinator的請求并執行SQL語句存取數據，節點之間也會互相通信。一般的，一個節點上的數據并不是全局的，數據節點不直接對外提供數據訪問。一個表的數據在數據節點上的分布存在兩種模式：復制模式和分片模式，復制模式下，一個表的數據在指定的節點上存在多個副本；分片模式下，一個表的數據按照一定的規則分布在多個數據節點上，這些節點共同保存一份完整的數據。這兩種模式的選擇是在創建表的時候執行CREATE TABLE語句指定的，具體語法如下：

CREATE TABLE table_name(...) DISTRIBUTE BY HASH(col)|MODULO(col)|ROUNDROBIN|REPLICATION TO NODE(nodename1,nodename2...)

可以看到，如果DISTRIBUTE BY 后面是REPLICATION，則是復制模式，其余則是分片模式，HASH指的是按照指定列的哈希值分布數據，MODULO指的是按照指定列的取摩運算分布數據，ROUNDROBIN指的是按照輪詢的方式分布數據。TO NODE指定了數據分布的節點范圍，如果沒有指定則默認所有數據節點參與數據分布。如果沒有指定分布模式，即使用普通的CREATE TABLE語句，PGXL會默認采用分片模式將數據分布到所有數據節點。

3. 主機規劃

GTM： server0： 192.168.51.140
Coordinator： server1： 192.168.51.141
Datanode1 Master： server2： 192.168.51.142
Datanode2 Master： server3： 192.168.51.143
Datanode1 Slave： server4： 192.168.51.144
Datanode2 Slave： server5： 192.168.51.145

—–Datanode3用于后面演示動態增刪節點—–
Datanode3 Master： server6： 192.168.51.146

【下面的步驟4-13，在所有節點上都要執行】

4. 修改主機hosts文件

# vi /etc/hosts 127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4 ::1 localhost localhost.localdomain localhost6 localhost6.localdomain6 192.168.51.140 server0 192.168.51.141 server1 192.168.51.142 server2 192.168.51.143 server3 192.168.51.144 server4 192.168.51.145 server5 192.168.51.146 server6

5. 安裝依賴的軟件包

openssh-clients, flex, bison, readline-devel, zlib-devel, openjade, docbook-style-dsssl, gcc
用rpm命令查看是否已安裝

# rpm -qa |grep xxx

如果沒裝可以用yum安裝

6. 卸載操作系統自帶的PostgreSQL

# rpm -qa |grep postgresql # rpm -qa |grep postgresql | xargs rpm -e --nodeps # rpm -qa |grep postgresql

7. 添加postgres用戶

建立組： # groupadd postgres 建立用戶： # useradd -m -d /home/postgres postgres -g postgres 初始化密碼： # passwd postgres 輸入密碼：12345678（舉例） 注：如果需要刪除postgres用戶，可以以root用戶執行命令： # userdel -r postgres

8. 配置免密登陸

root用戶

# ssh-keygen # ssh-copy-id -i ~/.ssh/id_rsa.pub root@server0 # ssh-copy-id -i ~/.ssh/id_rsa.pub root@server1 # ssh-copy-id -i ~/.ssh/id_rsa.pub root@server2 # ssh-copy-id -i ~/.ssh/id_rsa.pub root@server3 # ssh-copy-id -i ~/.ssh/id_rsa.pub root@server4 # ssh-copy-id -i ~/.ssh/id_rsa.pub root@server5 # ssh-copy-id -i ~/.ssh/id_rsa.pub root@server6

postgres用戶

$ ssh-keygen $ ssh-copy-id -i ~/.ssh/id_rsa.pub postgres@server0 $ ssh-copy-id -i ~/.ssh/id_rsa.pub postgres@server1 $ ssh-copy-id -i ~/.ssh/id_rsa.pub postgres@server2 $ ssh-copy-id -i ~/.ssh/id_rsa.pub postgres@server3 $ ssh-copy-id -i ~/.ssh/id_rsa.pub postgres@server4 $ ssh-copy-id -i ~/.ssh/id_rsa.pub postgres@server5 $ ssh-copy-id -i ~/.ssh/id_rsa.pub postgres@server6

如果配置完成后，發現ssh并不免密，可按下面操作進行完善：

chmod 755 /home/postgres chmod 700 /home/postgres/.ssh chmod 644 /home/postgres/.ssh/authorized_keys

9. 修改內核參數

在/etc/sysctl.conf中添加參數kernel.sem

# vi /etc/sysctl.conf kernel.sem = 50100 128256000 50100 2560

使參數生效

# sysctl -p

驗證參數是否生效。

# ipcs -ls

—— Semaphore Limits ——–
max number of arrays = 2560
max semaphores per array = 50100
max semaphores system wide = 128256000
max ops per semop call = 50100
semaphore max value = 32767

10. 配置防火墻

關閉防火墻

# systemctl stop firewalld # systemctl disable firewalld

或在防火墻中開放端口
遇到防護墻不能關閉的情況，可使用該步驟！
具體需要開放的端口參加（主機規劃部分），以5432為例：
使用這些命令來永久打開一個新端口（如TCP/5432）。

# sudo firewall-cmd --zone=public --add-port=5432/tcp --permanent # sudo firewall-cmd --reload

注：查看防火墻狀態命令：systemctl status firewalld
注：開啟防火墻：systemctl start firewalld
注：關閉防火墻：systemctl stop firewalld

11. 關閉SELinux

查看SELinux狀態，執行：

# /usr/sbin/sestatus -v

如果SELinux status參數為enabled即為開啟狀態
永久關閉SELinux，執行：

# vi /etc/selinux/config

將 SELINUX=enforcing 改為 SELINUX=disabled
重啟后生效

12. 安裝Postgres-XL軟件

解壓

# tar -jxvf postgres-xl-9.5r1.6.tar.bz2 # chown -R postgres:postgres postgres-xl-9.5r1.6

切換用戶

# su - postgres

安裝

$ cd postgres-xl-9.5r1.6 $ ./configure --prefix=/home/postgres/pgxl9.5 $ make $ make install

安裝擴展

$ cd contrib $ make $ make install

13. 配置環境變量

在文件.bash_profile中添加如下內容：

# su - postgres $ vi .bash_profileexport PGHOME=/home/postgres/pgxl9.5 export PGUSER=postgres export LD_LIBRARY_PATH=$PGHOME/lib:$LD_LIBRARY_PATH export PATH=$PGHOME/bin:$PATH

使環境變量生效：

$ source ~/.bashrc

驗證環境變量是否生效：

pg_ctl --version

顯示：pg_ctl (PostgreSQL) 9.5.8 (Postgres-XL 9.5r1.6)

14. 配置Postgres-XL集群

在GTM節點上以postgres用戶執行：

$ pgxc_ctl ---初次執行，會提示Error說沒有配置文件，忽略即可 PGXC prepare ---執行該命令將會生成一份配置文件模板 PGXC exit --退出 pgxc_ctl交互窗

執行完成后，在postgres用戶根目錄下，會生成一個pgxc_ctl目錄，編輯其中的pgxc_ctl.conf文件

$ vi pgxc_ctl.conf

修改為：

#!/usr/bin/env bash# pgxcInstallDir variable is needed if you invoke "deploy" command from pgxc_ctl utility. # If don't you don't need this variable. pgxcInstallDir=$PGHOME pgxlDATA=$PGHOME/data #---- OVERALL ----------------------------------------------------------------------------- # pgxcOwner=postgres # owner of the Postgres-XC databaseo cluster. Here, we use this# both as linus user and database user. This must be# the super user of each coordinator and datanode. pgxcUser=$pgxcOwner # OS user of Postgres-XC ownertmpDir=/tmp # temporary dir used in XC servers localTmpDir=$tmpDir # temporary dir used here locallyconfigBackup=n # If you want config file backup, specify y to this value. configBackupHost=pgxc-linker # host to backup config file configBackupDir=$HOME/pgxc # Backup directory configBackupFile=pgxc_ctl.bak # Backup file name --> Need to synchronize when original changed.#---- GTM ------------------------------------------------------------------------------------#---- GTM Master -----------------------------------------------#---- Overall ---- gtmName=gtm gtmMasterServer=server0 gtmMasterPort=6666 gtmMasterDir=$pgxlDATA/nodes/gtm#---- Configuration --- gtmExtraConfig=none # Will be added gtm.conf for both Master and Slave (done at initilization only) gtmMasterSpecificExtraConfig=none # Will be added to Master's gtm.conf (done at initialization only)#---- Coordinators ----------------------------------------------------------------------------------------------------#---- shortcuts ---------- coordMasterDir=$pgxlDATA/nodes/coord coordSlaveDir=$pgxlDATA/nodes/coord_slave coordArchLogDir=$pgxlDATA/nodes/coord_archlog#---- Overall ------------ coordNames=(coord1) # Master and slave use the same name coordPorts=(5432) # Master ports poolerPorts=(20004) # Master pooler ports coordPgHbaEntries=(0.0.0.0/0) # Assumes that all the coordinator (master/slave) accepts# the same connection# This entry allows only $pgxcOwner to connect.# If you'd like to setup another connection, you should# supply these entries through files specified below.#---- Master ------------- coordMasterServers=server1 # none means this master is not available coordMasterDirs=$coordMasterDir coordMaxWALsernder=10 # max_wal_senders: needed to configure slave. If zero value is specified,# it is expected to supply this parameter explicitly by external files# specified in the following. If you don't configure slaves, leave this value to zero. coordMaxWALSenders=$coordMaxWALsernder# max_wal_senders configuration for each coordinator.#---- Configuration files--- coordExtraConfig=coordExtraConfig # Extra configuration file for coordinators. # This file will be added to all the coordinators'# postgresql.conf # Pleae note that the following sets up minimum parameters which you may want to change. # You can put your postgresql.conf lines here. cat > $coordExtraConfig <<EOF #================================================ # Added to all the coordinator postgresql.conf # Original: $coordExtraConfig log_destination = 'stderr' logging_collector = on log_directory = 'pg_log' listen_addresses = '*' max_connections = 512 EOF# Additional Configuration file for specific coordinator master. # You can define each setting by similar means as above. coordSpecificExtraConfig=(none none) coordExtraPgHba=none # Extra entry for pg_hba.conf. This file will be added to all the coordinators' pg_hba.conf coordSpecificExtraPgHba=(none none)#---- Datanodes -------------------------------------------------------------------------------------------------------#---- Shortcuts -------------- datanodeMasterDir=$pgxlDATA/nodes/dn_master datanodeSlaveDir=$pgxlDATA/nodes/dn_slave datanodeArchLogDir=$pgxlDATA/nodes/datanode_archlog#---- Overall --------------- #primaryDatanode=datanode1 # Primary Node. # At present, xc has a priblem to issue ALTER NODE against the primay node. Until it is fixed, the test will be done # without this feature. primaryDatanode=datanode1 # Primary Node. datanodeNames=(datanode1 datanode2) datanodePorts=(5433 5433) # Master ports datanodePoolerPorts=(20005 20005) # Master pooler ports datanodePgHbaEntries=(0.0.0.0/0) # Assumes that all the coordinator (master/slave) accepts# the same connection# This list sets up pg_hba.conf for $pgxcOwner user.# If you'd like to setup other entries, supply them# through extra configuration files specified below. # Note: The above parameter is extracted as "host all all 0.0.0.0/0 trust". If you don't want # such setups, specify the value () to this variable and suplly what you want using datanodeExtraPgHba # and/or datanodeSpecificExtraPgHba variables. #datanodePgHbaEntries=(::1/128) # Same as above but for IPv6 addresses#---- Master ---------------- datanodeMasterServers=(server2 server3) # none means this master is not available.# This means that there should be the master but is down.# The cluster is not operational until the master is# recovered and ready to run. datanodeMasterDirs=($datanodeMasterDir/dn1 $datanodeMasterDir/dn2) datanodeMaxWalSender=10 # max_wal_senders: needed to configure slave. If zero value is # specified, it is expected this parameter is explicitly supplied# by external configuration files.# If you don't configure slaves, leave this value zero. datanodeMaxWALSenders=($datanodeMaxWalSender $datanodeMaxWalSender)# max_wal_senders configuration for each datanode#---- Slave ----------------- datanodeSlave=y # Specify y if you configure at least one coordiantor slave. Otherwise, the following# configuration parameters will be set to empty values.# If no effective server names are found (that is, every servers are specified as none),# then datanodeSlave value will be set to n and all the following values will be set to# empty values. datanodeSlaveServers=(server4 server5) # value none means this slave is not available datanodeSlavePorts=(15433 15433) # value none means this slave is not available datanodeSlavePoolerPorts=(20015 20015) # value none means this slave is not available datanodeSlaveSync=y # If datanode slave is connected in synchronized mode datanodeSlaveDirs=($datanodeSlaveDir $datanodeSlaveDir) datanodeArchLogDirs=( $datanodeArchLogDir $datanodeArchLogDir)# ---- Configuration files --- # You may supply your bash script to setup extra config lines and extra pg_hba.conf entries here. # These files will go to corresponding files for the master. # Or you may supply these files manually. datanodeExtraConfig=none # Extra configuration file for datanodes. This file will be added to all the # datanodes' postgresql.conf datanodeSpecificExtraConfig=(none none) datanodeExtraPgHba=none # Extra entry for pg_hba.conf. This file will be added to all the datanodes' postgresql.conf datanodeSpecificExtraPgHba=(none none)

15.初始化集群

在GTM節點上以postgres用戶執行：
初始化集群：

$ pgxc_ctl -c ~/pgxc_ctl/pgxc_ctl.conf init all

啟動集群：

$ pgxc_ctl -c /home/postgres/pgxc_ctl/pgxc_ctl.conf start all

停止集群

$ pgxc_ctl -c /home/postgres/pgxc_ctl/pgxc_ctl.conf stop all

16.刪除集群

在所有節點上以postgres用戶執行：

$ rm /home/postgres/pgxl9.5/data/nodes

總結

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