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一、准备环境
操作系统：CentOS Linux release 7.4
数据库版本：PostgreSQL 9.6.12
主库:192.168.189.152
从库:192.168.189.153
二、主机数据库部署
以下操作步骤请在两个节点进行，主库需要安装数据库软件以及初始化数据库，从库仅需要安装数据库软件即可无需初始化。
1、添加RPM源
[root@localhost opt]# yum install https://download.postgresql.org/pub/repos/yum/9.6/redhat/rhel-7-x86_64/pgdg-centos96-9.6-3.noarch.rpm
2、使用yum直接安装postgresql
[root@localhost opt]# yum -y install postgresql96-server postgresql96-contrib postgresql96-devel
3、创建postgresql文件目录以及用户组
创建数据文件目录
[root@localhost opt]# mkdir -p /data/pgdata/
创建pg用户组
[root@localhost opt]# groupadd pg
[root@localhost opt]# useradd -g pg pg
对数据文件目录授予权限
[root@localhost opt]# chown -R pg:pg /data/
[root@localhost opt]# chown -R pg:pg /var/run/postgresql
4、初始化数据库
注意：此步骤仅主库需要初始化，从库不需要
[pg@localhost ~]$ /usr/pgsql-9.6/bin/initdb -D /data/pgdata/
初始化过程：
The files belonging to this database system will be owned by user "pg".
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 /data/pgdata ... 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 ... ok
syncing data to disk ... 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. You can now start the database server using:
初始化完毕之后启动数据库
-->/usr/pgsql-9.6/bin/pg_ctl -D /data/pgdata/ -l logfile start
附停止命令：[postgres@localhost pgsql]$ pg_ctl stop -D /mydata/pgdata/备注：
5、添加环境变量
[pg@localhost ~]$ vi ~/.bash_profile
PGDATA=/data/pgdata
PGHOST=127.0.0.1
PGDATABASE=postgres
PGUSER=pg
PGPORT=5432
PATH=/usr/pgsql-9.6/bin:$PATH
export PATH
export PGDATA PGHOST PGDATABASE PGUSER PGPORT
export TMOUT=1000
export LD_LIBRARY_PATH=/usr/pgsql-9.6/lib
步骤6、7仅需在主库操作
6、修改监听配置
修改如下监听参数，是监听允许任何地址使用
[pg@localhost ~]$ vi /data/pgdata/postgresql.conf
listen_addresses = '*'
7、添加允许访问数据库的网段
在127.0.0.1下一段添加网段
[pg@localhost ~]$ vi /data/pgdata/pg_hba.conf
# IPv4 local connections:
host all all 127.0.0.1/32 trust
添加此行—->host all all 0.0.0.0/0 trust
三、主备数据库配置
3.1 主库配置
(1)创建复制用户，专门进行主从同步使用
[root@localhost ~]# su - pg
[pg@localhost ~]$ psql
postgres=# create user rpl superuser password '11111';
(2)主库上配置从库允许的网段
添加从库网段
[pg@localhost ~]$ vi /data/pgdata/pg_hba.conf
host replication rpl 192.168.0.0/0 md5
(3)修改主库参数文件
[pg@localhost ~]$ vi /data/pgdata/postgresql.conf
wal_level = hot_standby -->启用流复制
max_wal_senders=2 -->流复制允许连接进程
wal_keep_segments =64-->xlog目录中最多容纳多少个wal日志文件，超过了则删掉最初的几个。
max_connections = 1000 -->主库最大连接数
(4)重启主库服务
[pg@localhost ~]$ pg_ctl -D /data/pgdata/ -l logfile restart
3.2 从库配置
(1)基础备份
在从库无需拷贝主库的数据文件到本地，使用pg_basebackup可将主库的数据文件通过网络复制到本地、包括目录结构。
备注：如果主库存在自定义表空间，此操作会失败
[pg@localhost ~]$ pg_basebackup -h 192.168.212.152 -p 5432 -U rpl -F p -x -P -R -D /data/pgdata
Password:
46694/46694 kB (100%), 1/1 tablespace
传输完毕
(2) 从库配置文件配置
[pg@localhost ~]$ vi /data/pgdata/postgresql.conf
注释这三个参数wal_level，max_wal_senders,wal_keep_segments
修改
hot_standby = on ———>从库上执行只读操作
max_standby_streaming_delay = 30s -->从库接收主库日志最大超时时间
wal_receiver_status_interval = 10s -->从库向主库报告的最大时间间隔
hot_standby_feedback = off -->从库与主库发生冲突的反馈信息
max_connections = 1500 -->数据库最大连接数
3)创建恢复文件recovery.conf
recovery.conf 用于主库，从库切换时的参数配置。如果从库没有recovery.conf文件可拷贝模板
[pg@localhost pgdata]$ cp /usr/pgsql-9.6/share/recovery.conf.sample /data/pgdata/recovery.conf
[pg@localhost pgdata]$ vi /data/pgdata/recovery.conf
调整参数：
recovery_target_timeline = 'latest' moren
standby_mode = on
primary_conninfo = 'host=192.168.212.152 port=5432 user=rpl password=11111'
(4)启动从库服务
[pg@localhost pgdata]$ pg_ctl -D /data/pgdata/ -l logfile start
四、主从状态检查
查看主库sender进程信息
[root@localhost ~]# ps -ef|grep "wal sender process"
pg 7031 7015 0 17:04 ? 00:00:00 postgres: wal sender process rpl 192.168.212.153(49562) streaming 0/50001E8
查看从库receiver进程信息
[root@localhost ~]# ps -ef|grep "wal receiver"
pg 2360 2354 0 17:04 ? 00:00:00 postgres: wal receiver process streaming 0/50002C8
psql查询主从同步状态
postgres=# select usename,application_name,client_addr,state,sync_state from pg_stat_replication;
usename | application_name | client_addr | state | sync_state
---------+------------------+-----------------+-----------+------------
rpl | walreceiver | 192.168.212.153 | streaming | async-->异步
(1 row)
主库集群状态
[pg@localhost ~]$ pg_controldata /data/pgdata/|grep "Database cluster state"
Database cluster state: in production
从库集群状态
[pg@localhost ~]$ pg_controldata /data/pgdata/|grep "Database cluster state"
Database cluster state: in archive recovery
主从数据同步验证
主库建表、从库进行查询测试
主库：
pg=# insert into test values(1);
pg=# select * from test;
id
----
1
(1 row)
从库：
pg=# insert into test values(2);
ERROR: cannot execute INSERT in a read-only transaction
pg=# select * from test;
id
----
1
(1 row)
从库只有只读功能，无法做写入操作