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Postgres-XL叢集部署與管理指南

Postgres-XL是一個基於PostgreSQL資料庫的橫向擴充套件開源SQL資料庫叢集,具有足夠的靈活性來處理不同的資料庫工作負載,架構如下圖所示:

  • Web 2.0
  • 操作資料儲存
  • GIS的地理空間
  • 混合業務工作環境
  • OLTP 寫頻繁的業務
  • 多租戶服務提供商託管環境
  • 完全ACID,保持事務一致性
  • 包含JSON的Key-value 儲存
  • 需要MPP並行性商業智慧/大資料分析
    Postgres-XL叢集部署與管理指南
    各個元件介紹如下:
  • Global Transaction Monitor (GTM)
    全域性事務管理器,確保群集範圍內的事務一致性。GTM負責發放事務ID和快照作為其多版本併發控制的一部分。叢集也可以配置一個或多個備用GTM,以改進可用性。此外,可以在協調器間配置GTM代理, 可用於改善可擴充套件性,減少GTM的通訊量。
  • GTM Standby
    GTM的備用節點,在pgxc,pgxl中,GTM控制所有的全域性事務分配,如果出現問題,就會導致整個叢集不可用,為了增加可用性,增加該備用節點。當GTM出現問題時,GTM Standby可以升級為GTM,保證叢集正常工作。
  • GTM Proxy
    GTM需要與所有的Coordinators通訊,為了降低壓力,可以在每個Coordinator機器上部署一個GTM Proxy。
  • Coordinator
    協調員管理使用者會話,並與GTM和資料節點進行互動。協調員解析,並計劃查詢,並給語句中的每一個元件傳送下一個序列化的全域性性計劃。為節省機器,通常此服務和資料節點部署在一起。
  • Data Node
    資料節點是資料實際儲存的地方。資料的分佈可以由DBA來配置。為了提高可用性,可以配置資料節點的熱備以便進行故障轉移準備。
    總之,GTM是負責ACID的,保證分散式資料庫全域性事務一致性。得益於此,就算資料節點是分佈的,但是在主節點操作增刪改查事務時,就如同只操作一個數據庫一樣簡單。Coordinator是排程的,將操作指令傳送到各個資料節點。datanodes是資料節點,分散式儲存資料。

    1、安裝Postgres-XL

    1.1 叢集規劃

    四臺機器規劃如下圖所示:
    Postgres-XL叢集部署與管理指南

    1.2 作業系統配置

    禁用防火牆、selinux。各個節點通過yum安裝以下軟體包:

    [[email protected]
    ~]# yum -y install bzip2 readline-devel flex make gcc rsync

    另外,各個節點建立postgres使用者:

    [[email protected] ~]# groupadd postgres;useradd -g postgres postgres;echo redhat|passwd --stdin postgres

    使用者建立完成後,還需要在各個節點配置postgres使用者的免密碼登入(略)。然後編輯postgres使用者的環境變數,加入如下內容:

    [[email protected] ~]# mkdir /u01;chown postgres:postgres /u01
    [[email protected] ~]# su - postgres
    [[email protected] ~]$ vi .bashrc
    export PGUSER=postgres
    export PGHOME=/usr/local/pgsql
    export PGXC_CTL_HOME=/u01/pgxl/pgxc_ctl
    export LD_LIBRARY_PATH=$PGHOME/lib
    export LD_LIBRARY_PATH=${LD_LIBRARY_PATH}:/lib:/usr/lib:/usr/local/lib
    export PATH=$PGHOME/bin:$PATH:$HOME/.local/bin:$HOME/bin

    1.3 Postgres-XL安裝

    在各個節點以root使用者進行安裝,預設的安裝目錄是/usr/local/pgsql。

    [[email protected] ~]# wget https://×××w.postgres-xl.org/downloads/postgres-xl-10r1.tar.gz;tar -xzf postgres-xl-10r1.tar.gz;cd postgres-xl-10r1;./configure&&make&&make install
    [[email protected] postgres-xl-10r1]#  cd contrib;make && make install

    2、配置Postgres-XL叢集

    2.1 生成pgxc_ctl配置檔案

    在一個節點操作即可。

    [[email protected] ~]$ pgxc_ctl
    PGXC prepare
    PGXC exit

    編輯生成的配置檔案,內容如下:

    pgxcInstallDir=/u01
    pgxcOwner=$USER
    pgxcUser=$pgxcOwner
    tmpDir=/tmp
    localTmpDir=$tmpDir
    #--------GTM Master--------
    gtmName=gtm_master
    gtmMasterServer=pg01
    gtmMasterPort=20001
    gtmMasterDir=$pgxcInstallDir/pgxl/nodes/gtm
    gtmExtraConfig=none
    gtmMasterSpecificExtraConfig=none
    #-------GTM Slave---------
    gtmSlave=y
    gtmSlaveName=gtm_slave
    gtmSlaveServer=pg02 
    gtmSlavePort=20001
    gtmSlaveDir=$pgxcInstallDir/pgxl/nodes/gtm_slave
    gtmSlaveSpecificExtraConfig=none
    #-------GTM Proxy--------
    gtmProxyDir=$pgxcInstallDir/pgxl/nodes/gtm_pxy
    gtmProxy=y 
    gtmProxyNames=(gtm_pxy1 gtm_pxy2)
    gtmProxyServers=(pg01 pg02)
    gtmProxyPorts=(20002 20002)
    gtmProxyDirs=($gtmProxyDir $gtmProxyDir)
    gtmPxyExtraConfig=none
    gtmPxySpecificExtraConfig=(none none)
    #-----Coordinators Master----------
    coordMasterDir=$pgxcInstallDir/pgxl/nodes/coord
    coordSlaveDir=$pgxcInstallDir/pgxl/nodes/coord_slave
    coordArchLogDir=$pgxcInstallDir/pgxl/nodes/coord_archlog
    coordNames=(coord1 coord2)
    coordPorts=(5433 5433)
    poolerPorts=(5434 5434)
    coordPgHbaEntries=(0.0.0.0/0)
    coordMasterServers=(pg01 pg02)
    coordMasterDirs=($coordMasterDir $coordMasterDir)
    coordMaxWALsernder=5
    coordMaxWALSenders=($coordMaxWALsernder $coordMaxWALsernder)
    #-----Coordinators Slave----------
    coordSlave=y
    coordSlaveSync=y
    coordSlaveServers=(pg03 pg04)
    coordSlavePorts=(5433 5433)
    coordSlavePoolerPorts=(5434 5434)
    coordSlaveDirs=($coordSlaveDir $coordSlaveDir)
    coordArchLogDirs=($coordArchLogDir $coordArchLogDir)
    coordExtraConfig=coordExtraConfig
    cat > $coordExtraConfig <<EOF
    log_destination = 'stderr'
    logging_collector = on
    log_directory = 'pg_log'
    listen_addresses = '*'
    max_connections = 1000
    EOF
    coordSpecificExtraConfig=(none none)
    coordExtraPgHba=none
    coordSpecificExtraPgHba=(none none)
    #------Datanodes Master----------
    datanodeMasterDir=$pgxcInstallDir/pgxl/nodes/dnmaster
    datanodeSlaveDir=$pgxcInstallDir/pgxl/nodes/dnslave
    datanodeArchLogDir=$pgxcInstallDir/pgxl/nodes/dn_archlog
    primaryDatanode=pg03
    datanodeNames=(datanode1 datanode2)
    datanodePorts=(5436 5436)
    datanodePoolerPorts=(5437 5437)
    datanodePgHbaEntries=(0.0.0.0/0)
    datanodeMasterServers=(pg03 pg04)
    datanodeMasterDirs=($datanodeMasterDir $datanodeMasterDir)
    datanodeMaxWalSender=0 
    datanodeMaxWALSenders=($datanodeMaxWalSender $datanodeMaxWalSender)
    datanodeSlave=n

    2.2 Posgres-XL叢集初始化

    初始化完成後,會自動啟動叢集。

[[email protected] ~]$ pgxc_ctl -c /u01/pgxl/pgxc_ctl/pgxc_ctl.conf init all
/bin/bash
Installing pgxc_ctl_bash script as /u01/pgxl/pgxc_ctl_bash.
Installing pgxc_ctl_bash script as /u01/pgxl/pgxc_ctl_bash.
Reading configuration using /u01/pgxl/pgxc_ctl_bash --home /u01/pgxl --configuration /u01/pgxl/pgxc_ctl/pgxc_ctl.conf
Finished reading configuration.
******** PGXC_CTL START ***************

Current directory: /u01/pgxl
Initialize GTM master
The files belonging to this GTM system will be owned by user "postgres".
This user must also own the server process.

fixing permissions on existing directory /u01/pgxl/nodes/gtm ... ok
creating configuration files ... ok
creating control file ... ok

Success.
Done.
Start GTM master
server starting
Initialize GTM slave
The files belonging to this GTM system will be owned by user "postgres".
This user must also own the server process.

fixing permissions on existing directory /u01/pgxl/nodes/gtm_slave ... ok
creating configuration files ... ok
creating control file ... ok

Success.
Done.
Start GTM slavepgxc_ctl(13032):1811220924_48 server starting
Done.
Initialize all the gtm proxies.
Initializing gtm proxy gtm_pxy1.
Initializing gtm proxy gtm_pxy2.
The files belonging to this GTM system will be owned by user "postgres".
This user must also own the server process.

fixing permissions on existing directory /u01/pgxl/nodes/gtm_pxy ... ok
creating configuration files ... ok

Success.
The files belonging to this GTM system will be owned by user "postgres".
This user must also own the server process.

fixing permissions on existing directory /u01/pgxl/nodes/gtm_pxy ... ok
creating configuration files ... ok

Success.
Done.
Starting all the gtm proxies.
Starting gtm proxy gtm_pxy1.
Starting gtm proxy gtm_pxy2.
server starting
server starting
Done.
Initialize all the coordinator masters.
Initialize coordinator master coord1.
Initialize coordinator master coord2.
The files belonging to this database system will be owned by user "postgres".
This user must also own the server process.

The database cluster will be initialized with locale "en_US.UTF-8".
The default database encoding has accordingly been set to "UTF8".
The default text search configuration will be set to "english".

Data page checksums are disabled.

fixing permissions on existing directory /u01/pgxl/nodes/coord ... ok
creating subdirectories ... ok
selecting default max_connections ... 100
selecting default shared_buffers ... 128MB
selecting dynamic shared memory implementation ... posix
creating configuration files ... ok
running bootstrap script ... ok
performing post-bootstrap initialization ... creating cluster information ... ok
syncing data to disk ... ok
freezing database template0 ... ok
freezing database template1 ... ok
freezing database postgres ... ok

WARNING: enabling "trust" authentication for local connections
You can change this by editing pg_hba.conf or using the option -A, or
--auth-local and --auth-host, the next time you run initdb.

Success.
The files belonging to this database system will be owned by user "postgres".
This user must also own the server process.

The database cluster will be initialized with locale "en_US.UTF-8".
The default database encoding has accordingly been set to "UTF8".
The default text search configuration will be set to "english".

Data page checksums are disabled.

fixing permissions on existing directory /u01/pgxl/nodes/coord ... ok
creating subdirectories ... ok
selecting default max_connections ... 100
selecting default shared_buffers ... 128MB
selecting dynamic shared memory implementation ... posix
creating configuration files ... ok
running bootstrap script ... ok
performing post-bootstrap initialization ... creating cluster information ... ok
syncing data to disk ... ok
freezing database template0 ... ok
freezing database template1 ... ok
freezing database postgres ... ok

WARNING: enabling "trust" authentication for local connections
You can change this by editing pg_hba.conf or using the option -A, or
--auth-local and --auth-host, the next time you run initdb.

Success.
Done.
Starting coordinator master.
Starting coordinator master coord1
Starting coordinator master coord2
2018-11-22 09:24:59.252 CST [13950] LOG:  listening on IPv4 address "0.0.0.0", port 5433
2018-11-22 09:24:59.252 CST [13950] LOG:  listening on IPv6 address "::", port 5433
2018-11-22 09:24:59.254 CST [13950] LOG:  listening on Unix socket "/tmp/.s.PGSQL.5433"
2018-11-22 09:24:59.302 CST [13950] LOG:  redirecting log output to logging collector process
2018-11-22 09:24:59.302 CST [13950] HINT:  Future log output will appear in directory "pg_log".
2018-11-22 09:24:59.060 CST [13633] LOG:  listening on IPv4 address "0.0.0.0", port 5433
2018-11-22 09:24:59.061 CST [13633] LOG:  listening on IPv6 address "::", port 5433
2018-11-22 09:24:59.062 CST [13633] LOG:  listening on Unix socket "/tmp/.s.PGSQL.5433"
2018-11-22 09:24:59.109 CST [13633] LOG:  redirecting log output to logging collector process
2018-11-22 09:24:59.109 CST [13633] HINT:  Future log output will appear in directory "pg_log".
Done.
Initialize all the coordinator slaves.
Initialize the coordinator slave coord1.
Initialize the coordinator slave coord2.
Done.
Starting all the coordinator slaves.
Starting coordinator slave coord1.
Starting coordinator slave coord2.
2018-11-22 09:25:05.987 CST [13330] LOG:  listening on IPv4 address "0.0.0.0", port 5433
2018-11-22 09:25:05.987 CST [13330] LOG:  listening on IPv6 address "::", port 5433
2018-11-22 09:25:05.989 CST [13330] LOG:  listening on Unix socket "/tmp/.s.PGSQL.5433"
2018-11-22 09:25:06.039 CST [13330] LOG:  redirecting log output to logging collector process
2018-11-22 09:25:06.039 CST [13330] HINT:  Future log output will appear in directory "pg_log".
2018-11-22 09:25:05.517 CST [13266] LOG:  listening on IPv4 address "0.0.0.0", port 5433
2018-11-22 09:25:05.517 CST [13266] LOG:  listening on IPv6 address "::", port 5433
2018-11-22 09:25:05.518 CST [13266] LOG:  listening on Unix socket "/tmp/.s.PGSQL.5433"
2018-11-22 09:25:05.567 CST [13266] LOG:  redirecting log output to logging collector process
2018-11-22 09:25:05.567 CST [13266] HINT:  Future log output will appear in directory "pg_log".
Done
Initialize all the datanode masters.
Initialize the datanode master datanode1.
Initialize the datanode master datanode2.
The files belonging to this database system will be owned by user "postgres".
This user must also own the server process.

The database cluster will be initialized with locale "en_US.UTF-8".
The default database encoding has accordingly been set to "UTF8".
The default text search configuration will be set to "english".

Data page checksums are disabled.

fixing permissions on existing directory /u01/pgxl/nodes/dnmaster ... ok
creating subdirectories ... ok
selecting default max_connections ... 100
selecting default shared_buffers ... 128MB
selecting dynamic shared memory implementation ... posix
creating configuration files ... ok
running bootstrap script ... ok
performing post-bootstrap initialization ... creating cluster information ... ok
syncing data to disk ... ok
freezing database template0 ... ok
freezing database template1 ... ok
freezing database postgres ... ok

WARNING: enabling "trust" authentication for local connections
You can change this by editing pg_hba.conf or using the option -A, or
--auth-local and --auth-host, the next time you run initdb.

Success.
The files belonging to this database system will be owned by user "postgres".
This user must also own the server process.

The database cluster will be initialized with locale "en_US.UTF-8".
The default database encoding has accordingly been set to "UTF8".
The default text search configuration will be set to "english".

Data page checksums are disabled.

fixing permissions on existing directory /u01/pgxl/nodes/dnmaster ... ok
creating subdirectories ... ok
selecting default max_connections ... 100
selecting default shared_buffers ... 128MB
selecting dynamic shared memory implementation ... posix
creating configuration files ... ok
running bootstrap script ... ok
performing post-bootstrap initialization ... creating cluster information ... ok
syncing data to disk ... ok
freezing database template0 ... ok
freezing database template1 ... ok
freezing database postgres ... ok

WARNING: enabling "trust" authentication for local connections
You can change this by editing pg_hba.conf or using the option -A, or
--auth-local and --auth-host, the next time you run initdb.

Success.
Done.
Starting all the datanode masters.
Starting datanode master datanode1.
Starting datanode master datanode2.
2018-11-22 09:25:15.129 CST [13604] LOG:  listening on IPv4 address "0.0.0.0", port 5436
2018-11-22 09:25:15.130 CST [13604] LOG:  listening on IPv6 address "::", port 5436
2018-11-22 09:25:15.131 CST [13604] LOG:  listening on Unix socket "/tmp/.s.PGSQL.5436"
2018-11-22 09:25:15.148 CST [13604] LOG:  redirecting log output to logging collector process
2018-11-22 09:25:15.148 CST [13604] HINT:  Future log output will appear in directory "pg_log".
2018-11-22 09:25:14.657 CST [13539] LOG:  listening on IPv4 address "0.0.0.0", port 5436
2018-11-22 09:25:14.657 CST [13539] LOG:  listening on IPv6 address "::", port 5436
2018-11-22 09:25:14.659 CST [13539] LOG:  listening on Unix socket "/tmp/.s.PGSQL.5436"
2018-11-22 09:25:14.676 CST [13539] LOG:  redirecting log output to logging collector process
2018-11-22 09:25:14.676 CST [13539] HINT:  Future log output will appear in directory "pg_log".
Done.
ALTER NODE coord1 WITH (HOST='pg01', PORT=5433);
ALTER NODE
CREATE NODE coord2 WITH (TYPE='coordinator', HOST='pg02', PORT=5433);
CREATE NODE
CREATE NODE datanode1 WITH (TYPE='datanode', HOST='pg03', PORT=5436);
CREATE NODE
CREATE NODE datanode2 WITH (TYPE='datanode', HOST='pg04', PORT=5436);
CREATE NODE
SELECT pgxc_pool_reload();
 pgxc_pool_reload 
------------------
 t
(1 row)

CREATE NODE coord1 WITH (TYPE='coordinator', HOST='pg01', PORT=5433);
CREATE NODE
ALTER NODE coord2 WITH (HOST='pg02', PORT=5433);
ALTER NODE
CREATE NODE datanode1 WITH (TYPE='datanode', HOST='pg03', PORT=5436);
CREATE NODE
CREATE NODE datanode2 WITH (TYPE='datanode', HOST='pg04', PORT=5436);
CREATE NODE
SELECT pgxc_pool_reload();
 pgxc_pool_reload 
------------------
 t
(1 row)

Done.
EXECUTE DIRECT ON (datanode1) 'CREATE NODE coord1 WITH (TYPE=''coordinator'', HOST=''pg01'', PORT=5433)';
EXECUTE DIRECT
EXECUTE DIRECT ON (datanode1) 'CREATE NODE coord2 WITH (TYPE=''coordinator'', HOST=''pg02'', PORT=5433)';
EXECUTE DIRECT
EXECUTE DIRECT ON (datanode1) 'ALTER NODE datanode1 WITH (TYPE=''datanode'', HOST=''pg03'', PORT=5436)';
EXECUTE DIRECT
EXECUTE DIRECT ON (datanode1) 'CREATE NODE datanode2 WITH (TYPE=''datanode'', HOST=''pg04'', PORT=5436)';
EXECUTE DIRECT
EXECUTE DIRECT ON (datanode1) 'SELECT pgxc_pool_reload()';
 pgxc_pool_reload 
------------------
 t
(1 row)

EXECUTE DIRECT ON (datanode2) 'CREATE NODE coord1 WITH (TYPE=''coordinator'', HOST=''pg01'', PORT=5433)';
EXECUTE DIRECT
EXECUTE DIRECT ON (datanode2) 'CREATE NODE coord2 WITH (TYPE=''coordinator'', HOST=''pg02'', PORT=5433)';
EXECUTE DIRECT
EXECUTE DIRECT ON (datanode2) 'CREATE NODE datanode1 WITH (TYPE=''datanode'', HOST=''pg03'', PORT=5436)';
EXECUTE DIRECT
EXECUTE DIRECT ON (datanode2) 'ALTER NODE datanode2 WITH (TYPE=''datanode'', HOST=''pg04'', PORT=5436)';
EXECUTE DIRECT
EXECUTE DIRECT ON (datanode2) 'SELECT pgxc_pool_reload()';
 pgxc_pool_reload 
------------------
 t
(1 row)

Done.

通過查詢pgxc_node表可以獲取叢集節點資訊:
Postgres-XL叢集部署與管理指南

2.3 Posgres-XL叢集啟動與關閉

[[email protected] ~]$ pgxc_ctl -c /u01/pgxl/pgxc_ctl/pgxc_ctl.conf stop all
[[email protected] ~]$ pgxc_ctl -c /u01/pgxl/pgxc_ctl/pgxc_ctl.conf start all

2.4 Posgres-XL叢集服務監控

[[email protected] ~]$ pgxc_ctl -c /u01/pgxl/pgxc_ctl/pgxc_ctl.conf monitor all
/bin/bash
Installing pgxc_ctl_bash script as /u01/pgxl/pgxc_ctl_bash.
Installing pgxc_ctl_bash script as /u01/pgxl/pgxc_ctl_bash.
Reading configuration using /u01/pgxl/pgxc_ctl_bash --home /u01/pgxl --configuration /u01/pgxl/pgxc_ctl/pgxc_ctl.conf
Finished reading configuration.
   ******** PGXC_CTL START ***************

Current directory: /u01/pgxl
Running: gtm master
Running: gtm slave
Running: gtm proxy gtm_pxy1
Running: gtm proxy gtm_pxy2
Running: coordinator master coord1
Running: coordinator slave coord1
Running: coordinator master coord2
Running: coordinator slave coord2
Running: datanode master datanode1
Running: datanode slave datanode1
Running: datanode master datanode2
Running: datanode slave datanode2

3、測試Posgres-XL叢集

3.1 建立測試表並插入資料

建立一張log表,然後插入500條資料,如下:

[[email protected] ~]$ psql -p5433
psql (PGXL 10r1, based on PG 10.5 (Postgres-XL 10r1))
Type "help" for help.
postgres=# CREATE TABLE log (id numeric NOT NULL,stamp timestamp with time zone,user_id numeric);
postgres=# copy log from '/u02/tmp/log.csv' with csv;
COPY 499

3.2 查看錶資料分佈資訊

可以在協調器節點或者各個資料節點檢視,這裡使用下面的語句直接統計每個資料節點的表資料分佈情況:

postgres=# SELECT xc_node_id, count(*) FROM log GROUP BY xc_node_id;

Postgres-XL叢集部署與管理指南

3.3 建表說明

  • distribute表
    預設情況下,系統會將插入的資料,按照拆分規則,分配到不同的datanode節點中儲存,也就是sharding技術。每個datanode節點只儲存了部分資料,通過coordinate節點可以查詢完整的資料檢視。上面建立的log表就是distribute表。建表語法如下:
    postgres=# CREATE TABLE log (id numeric NOT NULL,stamp timestamp with time zone,user_id numeric) distribute by hash(id);

    distribute表資料分佈如下圖:
    Postgres-XL叢集部署與管理指南

  • replication表
    各個datanode節點中,表的資料完全相同。也就是說,在插入資料時,系統會分別在每個datanode節點插入相同資料。讀資料時,只需要讀任意一個datanode節點上的資料即可。建表語法如下:
    postgres=# CREATE TABLE log2 (id numeric NOT NULL,stamp timestamp with time zone,user_id numeric) distribute by replication;
    postgres=# copy log2 from '/u02/tmp/log.csv' with csv;

    replication表資料分佈如下圖:
    Postgres-XL叢集部署與管理指南
    不論在哪個資料節點查詢,顯示的結果都一樣的。

    4、Postgres-XL Slave節點管理

    為了提高叢集可用性,以下配置資料節點的熱備以便進行故障轉移切換。

    4.1 新增Slave資料節點

    在gtm節點操作,新增兩個slave資料節點,如下:

[[email protected] ~]$ pgxc_ctl -c /u01/pgxl/pgxc_ctl/pgxc_ctl.conf
/bin/bash
Installing pgxc_ctl_bash script as /u01/pgxl/pgxc_ctl_bash.
Installing pgxc_ctl_bash script as /u01/pgxl/pgxc_ctl_bash.
Reading configuration using /u01/pgxl/pgxc_ctl_bash --home /u01/pgxl --configuration /u01/pgxl/pgxc_ctl/pgxc_ctl.conf
Finished reading configuration.
   ******** PGXC_CTL START ***************

Current directory: /u01/pgxl
PGXC add datanode slave datanode1 pg05 5436 5437 /u01/pgxl/nodes/dnslave /u01/pgxl/nodes/dn_slave_war /u01/pgxl/nodes/dn_archlog
PGXC add datanode slave datanode2 pg06 5436 5437 /u01/pgxl/nodes/dnslave /u01/pgxl/nodes/dn_slave_war /u01/pgxl/nodes/dn_archlog

4.2 主備節點切換

檢查所有服務執行正常:

[[email protected] ~]$ pgxc_ctl -c /u01/pgxl/pgxc_ctl/pgxc_ctl.conf monitor all
/bin/bash
Installing pgxc_ctl_bash script as /u01/pgxl/pgxc_ctl_bash.
Installing pgxc_ctl_bash script as /u01/pgxl/pgxc_ctl_bash.
Reading configuration using /u01/pgxl/pgxc_ctl_bash --home /u01/pgxl --configuration /u01/pgxl/pgxc_ctl/pgxc_ctl.conf
Finished reading configuration.
   ******** PGXC_CTL START ***************

Current directory: /u01/pgxl
Running: gtm master
Running: gtm slave
Running: gtm proxy gtm_pxy1
Running: gtm proxy gtm_pxy2
Running: coordinator master coord1
Running: coordinator slave coord1
Running: coordinator master coord2
Running: coordinator slave coord2
Running: datanode master datanode1
Running: datanode slave datanode1
Running: datanode master datanode2
Running: datanode slave datanode2

當前的主節點是pg03和pg04,如下圖:
Postgres-XL叢集部署與管理指南
切換主備節點:

[[email protected] ~]$ pgxc_ctl -c /u01/pgxl/pgxc_ctl/pgxc_ctl.conf monitor all
/bin/bash
Installing pgxc_ctl_bash script as /u01/pgxl/pgxc_ctl_bash.
Installing pgxc_ctl_bash script as /u01/pgxl/pgxc_ctl_bash.
Reading configuration using /u01/pgxl/pgxc_ctl_bash --home /u01/pgxl --configuration /u01/pgxl/pgxc_ctl/pgxc_ctl.conf
Finished reading configuration.
   ******** PGXC_CTL START ***************

Current directory: /u01/pgxl
Running: gtm master
Running: gtm slave
Running: gtm proxy gtm_pxy1
Running: gtm proxy gtm_pxy2
Running: coordinator master coord1
Running: coordinator slave coord1
Running: coordinator master coord2
Running: coordinator slave coord2
Running: datanode master datanode1
Running: datanode slave datanode1
Running: datanode master datanode2
Running: datanode slave datanode2
[[email protected] ~]$ pgxc_ctl -c /u01/pgxl/pgxc_ctl/pgxc_ctl.conf failover datanode datanode1 datanode2
/bin/bash
Installing pgxc_ctl_bash script as /u01/pgxl/pgxc_ctl_bash.
Installing pgxc_ctl_bash script as /u01/pgxl/pgxc_ctl_bash.
Reading configuration using /u01/pgxl/pgxc_ctl_bash --home /u01/pgxl --configuration /u01/pgxl/pgxc_ctl/pgxc_ctl.conf
Finished reading configuration.
   ******** PGXC_CTL START ***************

Current directory: /u01/pgxl
Failover specified datanodes.
Failover the datanode datanode1.
Failover datanode datanode1 using GTM itself
Actual Command: ssh [email protected] "( pg_ctl promote -Z datanode -D /u01/pgxl/nodes/dnslave ) > /tmp/pg01_STDOUT_4264_0 2>&1" < /dev/null > /dev/null 2>&1
Bring remote stdout: scp [email protected]:/tmp/pg01_STDOUT_4264_0 /tmp/STDOUT_4264_1 > /dev/null 2>&1
Actual Command: ssh [email protected] "( pg_ctl restart -w -Z datanode -D /u01/pgxl/nodes/dnslave -o -i; sleep 1 ) > /tmp/pg01_STDOUT_4264_2 2>&1" < /dev/null > /dev/null 2>&1
Bring remote stdout: scp [email protected]:/tmp/pg01_STDOUT_4264_2 /tmp/STDOUT_4264_3 > /dev/null 2>&1
2018-11-23 14:52:34.655 CST [26323] LOG:  listening on IPv4 address "0.0.0.0", port 5436
2018-11-23 14:52:34.655 CST [26323] LOG:  listening on IPv6 address "::", port 5436
2018-11-23 14:52:34.657 CST [26323] LOG:  listening on Unix socket "/tmp/.s.PGSQL.5436"
2018-11-23 14:52:34.675 CST [26323] LOG:  redirecting log output to logging collector process
2018-11-23 14:52:34.675 CST [26323] HINT:  Future log output will appear in directory "pg_log".
ALTER NODE
 pgxc_pool_reload 
------------------
 t
(1 row)

EXECUTE DIRECT
 pgxc_pool_reload 
------------------
 t
(1 row)

EXECUTE DIRECT
 pgxc_pool_reload 
------------------
 t
(1 row)

ALTER NODE
 pgxc_pool_reload 
------------------
 t
(1 row)

Failover the datanode datanode2.
Failover datanode datanode2 using GTM itself
Actual Command: ssh [email protected] "( pg_ctl promote -Z datanode -D /u01/pgxl/nodes/dnslave ) > /tmp/pg01_STDOUT_4264_4 2>&1" < /dev/null > /dev/null 2>&1
Bring remote stdout: scp [email protected]:/tmp/pg01_STDOUT_4264_4 /tmp/STDOUT_4264_5 > /dev/null 2>&1
Actual Command: ssh [email protected] "( pg_ctl restart -w -Z datanode -D /u01/pgxl/nodes/dnslave -o -i; sleep 1 ) > /tmp/pg01_STDOUT_4264_6 2>&1" < /dev/null > /dev/null 2>&1
Bring remote stdout: scp [email protected]:/tmp/pg01_STDOUT_4264_6 /tmp/STDOUT_4264_7 > /dev/null 2>&1
2018-11-23 14:52:38.607 CST [26317] LOG:  listening on IPv4 address "0.0.0.0", port 5436
2018-11-23 14:52:38.607 CST [26317] LOG:  listening on IPv6 address "::", port 5436
2018-11-23 14:52:38.609 CST [26317] LOG:  listening on Unix socket "/tmp/.s.PGSQL.5436"
2018-11-23 14:52:38.628 CST [26317] LOG:  redirecting log output to logging collector process
2018-11-23 14:52:38.628 CST [26317] HINT:  Future log output will appear in directory "pg_log".
ALTER NODE
 pgxc_pool_reload 
------------------
 t
(1 row)

EXECUTE DIRECT
 pgxc_pool_reload 
------------------
 t
(1 row)

EXECUTE DIRECT
 pgxc_pool_reload 
------------------
 t
(1 row)

ALTER NODE
 pgxc_pool_reload 
------------------
 t
(1 row)

Done.
[[email protected] ~]$ pgxc_ctl -c /u01/pgxl/pgxc_ctl/pgxc_ctl.conf monitor all
/bin/bash
Installing pgxc_ctl_bash script as /u01/pgxl/pgxc_ctl_bash.
Installing pgxc_ctl_bash script as /u01/pgxl/pgxc_ctl_bash.
Reading configuration using /u01/pgxl/pgxc_ctl_bash --home /u01/pgxl --configuration /u01/pgxl/pgxc_ctl/pgxc_ctl.conf
Finished reading configuration.
   ******** PGXC_CTL START ***************

Current directory: /u01/pgxl
Running: gtm master
Running: gtm slave
Running: gtm proxy gtm_pxy1
Running: gtm proxy gtm_pxy2
Running: coordinator master coord1
Running: coordinator slave coord1
Running: coordinator master coord2
Running: coordinator slave coord2
Running: datanode master datanode1
Running: datanode master datanode2

切換完成後,舊的master節點作廢,而新建的兩個slave節點就轉變為master節點角色。
Postgres-XL叢集部署與管理指南

4.3 刪除Slave節點

[[email protected] ~]$ pgxc_ctl -c /u01/pgxl/pgxc_ctl/pgxc_ctl.conf remove datanode slave datanode1 clean
[[email protected] ~]$ pgxc_ctl -c /u01/pgxl/pgxc_ctl/pgxc_ctl.conf remove datanode slave datanode2 clean