实现目标：主库可读可写，从库只读，两库之间为流式复制，若主库宕机，从库自动升级成主库
环境 Debian 9

软件介绍

Repmgr是一个开源工具套件，用于管理PostgreSQL服务器集群中的复制和故障转移。它使用工具来增强PostgreSQL的内置热备份功能，以设置备用服务器，监控复制以及执行管理任务，例如故障转移或手动切换操作。

Repmgr 4.1版文档地址 https://repmgr.org/docs/4.1/index.html

Pgpool是一个工作在PostgreSQL多服务器和PostgreSQL数据库客户端之间的中间件。
pgpool http://www.pgpool.net/docs/latest/en/html/
pgpoolAdmin http://www.pgpool.net/docs/pgpoolAdmin/index_en.html

Pgpool

Pgpool

安装步骤

wget http://www.pgpool.net/download.php?f=pgpool-II-4.0.1.tar.gz
tar -xzvf download.php\?f\=pgpool-II-4.0.1.tar.gz
./configure
make
make install
ln -s /usr/local/lib/libpcp.so.1 /usr/lib/libpcp.so.1
cd /usr/local/etc
cp pgpool.conf.sample-replication pgpool.conf
#配置局域网段/指定IP trust
#host    all         all         192.168.0.0/16        trust
cp pool_hba.conf.sample pool_hba.conf
cp pcp.conf.sample pcp.conf
chmod 644 pgpool.conf pool_hba.conf pcp.conf
chown www-data pgpool.conf pool_hba.conf pcp.conf
#配置service
cd /lib/systemd/system
vim pgpool.service
ln -s /lib/systemd/system/pgpool.service /etc/systemd/system/multi-user.target.wants/pgpool.service
useradd pgpool
passwd pgpool
systemctl start pgpool
# 配置pgpool.conf的图形化页面工具
wget http://www.pgpool.net/download.php?f=pgpoolAdmin-4.0.0.tar.gz
tar -xzvf download.php?f=pgpoolAdmin-4.0.0.tar.gz
apt -y install php-fpm php-pgsql
mv pgpoolAdmin-4.0.0 /var/www/pgpoolAdmin
vim /etc/nginx/sites-avaliable/pgpool-nginx.conf
cd /var/www/pgpoolAdmin
chmod 777 templates_c
chown www-data /var/www/pgpoolAdmin/conf/pgmgt.conf.php
chmod 644 /var/www/pgpoolAdmin/conf/pgmgt.conf.php
# 配置好nginx后 访问 /install/index.php

Repmgr

apt-get install postgresql-11-repmgr
# 分别copy主库从库的repmgr.conf文件
# ----master start-----
createuser -s repmgr
createdb repmgr -O repmgr
psql -U repmgr
  # 执行SQL
  ALTER USER repmgr SET search_path TO repmgr, "$user", public;
# 
repmgr -f /etc/postgresql/11/main/repmgr.conf primary register
# -----master end ----
# -----slave start ----
/usr/lib/postgresql/11/bin/pg_ctl -w -D /var/lib/postgresql/11/main stop
repmgr -h node1 -U repmgr -d repmgr -f  /etc/postgresql/11/main/repmgr.conf standby clone --force
/usr/lib/postgresql/11/bin/pg_ctl -D /var/lib/postgresql/11/main -l /var/log/postgresql/postgresql-11-main.log -w -o "-c config_file=/etc/postgresql/11/main/postgresql.conf" start
repmgr standby register -f /etc/postgresql/11/main/repmgr.conf
repmgr -f /etc/postgresql/11/main/repmgr.conf cluster show
vim ~/.bashrc
  alias repmgrf='repmgr -f /etc/postgresql/11/main/repmgr.conf'
# -----slave end ----

# repmgrd (监控repmgr)
repmgrd -f /etc/postgresql/11/main/repmgr.conf --pid-file /tmp/repmgrd.pid --daemonize > /var/log/postgresql/repmgr.log 2>&1

postgres配置

postgresql主要修改配置

#Master: postgresql.conf
shared_preload_libraries = 'repmgr'
wal_level = 'hot_standby'
archive_mode = on      
  
#Slave: postgresql.conf
shared_preload_libraries = 'repmgr'
hot_standby = on
hot_standby_feedback = on   

从库的recovery.conf

# slave
# /var/lib/postgresql/11/main/recovery.conf
standby_mode = 'on'
primary_conninfo = 'host=node1 user=repmgr application_name=pg_node2 connect_timeout=2'
recovery_target_timeline = 'latest'

部分配置文件sample

pgpool.service

[Unit]

Description=Pgpool-II

After=syslog.target network.target

Wants=network.target

[Service]
User=pgpool

Type=forking

ExecStartPre=/bin/sh -c "rm -f /tmp/.s.PGSQL.9999”

ExecStartPre=/bin/sh -c "rm -f /tmp/.s.PGSQL.9898"

RestartSec=5s

ExecStart=/usr/local/bin/pgpool -f /usr/local/etc/pgpool.conf -a /usr/local/etc/pool_hba.conf -F /usr/local/etc/pcp.conf

ExecStop=/usr/local/bin/pgpool -f /usr/local/etc/pgpool.conf -a /usr/local/etc/pool_hba.conf -F /usr/local/etc/pcp.conf stop

ExecReload=/usr/local/bin/pgpool -f /usr/local/etc/pgpool.conf -a /usr/local/etc/pool_hba.conf -F /usr/local/etc/pcp.conf reload

Restart=always

StandardOutput=syslog

StandardError=syslog

SyslogIdentifier=my_pgpool

PIDFile=/var/run/pgpool/pgpool.pid

[Install]

WantedBy=multi-user.target

pgpool-nginx.conf

server {
        listen 80;
        server_name  pgpool.xxx.com;
        location ~ \.php$ {
                        root /var/www/html/pgpoolAdmin;
                        index index.php;
                        #fastcgi_pass 127.0.0.1:9000;
                        fastcgi_pass unix:/run/php/php7.0-fpm.sock;
                        fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
                        include fastcgi_params;
                }
        location / {
                root /var/www/html/pgpoolAdmin;
        }

}

repmgr.conf

# https://raw.githubusercontent.com/2ndQuadrant/repmgr/master/repmgr.conf.sample
node_id=1
node_name=pg_node1
conninfo='host=node1 user=repmgr dbname=repmgr connect_timeout=2'
data_directory='/var/lib/postgresql/11/main'

monitoring_history=yes
log_file='/var/log/postgresql/repmgr.log'

service_start_command = '/usr/lib/postgresql/11/bin/pg_ctl -D /var/lib/postgresql/11/main -l /var/log/postgresql/postgresql-11-main.log -w -o "-c config_file=/etc/postgresql/11/main/postgresql.conf" start'
service_restart_command = '/usr/lib/postgresql/11/bin/pg_ctl -w -D /var/lib/postgresql/11/main -l /var/log/postgresql/postgresql-11-main.log restart'
service_reload_command = '/usr/lib/postgresql/11/bin/pg_ctl -w -D /var/lib/postgresql/11/main -l /var/log/postgresql/postgresql-11-main.log reload'

failover=automatic
promote_command='repmgr standby promote -f /etc/postgresql/11/main/repmgr.conf --log-to-file'
follow_command='repmgr standby follow -f /etc/postgresql/11/main/repmgr.conf --log-to-file --upstream-node-id=2'

promote_check_timeout=30                # The length of time (in seconds) to wait
                                        # for the new primary to finish promoting

primary_follow_timeout=30               # The max length of time (in seconds) to wait
                                        # for the new primary to become available

#event_notification_command='/data/send_mail "repmgr event notification" "node Id： %n \n事件： %e \n成功(1?)： %s \n时间： %t \n详情： %d"'