PostgreSQL+patroni+etcd+haproxy+keepalived 高可用架构
部署环境
部署postgresql-15 一主二从：
| role | 主机 | 组件 |
| 主库 | node203 192.168.56.203 | pg15.5 Patroni、Etcd，haproxy、keepalived |
| 从库 | node204 192.168.56.204 | pg15.5 Patroni、Etcd，haproxy、keepalived |
| 从库 | node206 192.168.56.206 | pg15.5 Patroni、Etcd，haproxy、keepalived |
PostgreSQL version and Configuration：
| Item | Value | Detail |
|---|---|---|
| PostgreSQL Version | 15.5 | - |
| port | 5432 | - |
| $PGDATA | /data/pgsqldata | - |
| Archive mode | on | /data/archive |
| Replication Slots | Enable | - |
etcd version and Configuration：
| Item | Value | Detail |
|---|---|---|
| Pgpool-II Version | 4.4.4 | - |
| port | 9999 | Pgpool-II accepts connections，可以通过vip + 9999端口 连接到后端的pg数据库 |
| 9898 | PCP process accepts connections | |
| 9000 | watchdog accepts connections | |
| 9694 | UDP port for receiving Watchdog's heartbeat signal | |
| Config file | /etc/pgpool-II/pgpool.conf | Pgpool-II config file |
| Pgpool-II start user | postgres (Pgpool-II 4.1 or later) | Pgpool-II 4.0 or before, the default startup user is root |
| Running mode | streaming replication mode | - |
| Watchdog | on | Life check method: heartbeat |
1.配置PostgreSQL-15的一主三从复制
参见：https://blog.csdn.net/longway111/article/details/134564919
1.1 安装PostgreSQL15
参见：https://blog.csdn.net/longway111/article/details/134437917
# Install the repository RPM:
yum install -y https://download.postgresql.org/pub/repos/yum/reporpms/EL-7-x86_64/pgdg-redhat-repo-latest.noarch.rpm# Install PostgreSQL:
yum install -y postgresql15-server# psql -V
psql (PostgreSQL) 15.5
从库仅需安装软件即可无需配置，后面通过pg_basebackup同步主库数据库目录下的所有文件。
1.2 主库初始化及配置
参见：https://blog.csdn.net/longway111/article/details/134437917
修改数据目录
#初始化前修改数据库路径
vi /usr/lib/systemd/system/postgresql-15.service
# Location of database directory
# Environment=PGDATA=/var/lib/pgsql/15/data/
Environment=PGDATA=/data/pgsqldata/
#修改数据库路径的所属用户和用户组
mkdir -p /data/pgsqldata
chown -R postgres:postgres /data
chmod -R 700 /data/pgsqldata
#修改后执行reload
systemctl daemon-reload
初始化PostgreSQL
#初始化PostgreSQL
# /usr/pgsql-15/bin/postgresql-15-setup initdb
创建归档目录
# su - postgres
$ mkdir -p /data/archive
chown -R postgres:postgres /data
chmod -R 700 /data/archive
配置归档相关参数
# su - postgres
$ cp /data/pgsqldata/postgresql.conf /data/pgsqldata/postgresql.conf.ori
#最简参数
cat > /data/pgsqldata/postgresql.conf << EOF
listen_addresses = '*'
port=5432
archive_mode = on
archive_command = 'cp "%p" "/data/archive/%f"'
max_wal_senders = 10
max_replication_slots = 10
wal_level = replica
hot_standby = on
wal_log_hints = on
EOFEnable wal_log_hints to use pg_rewind. Since the Primary may become a Standby later, we set hot_standby = on.
启动数据库
systemctl start postgresql-15
或
su - postgres
$ /usr/pgsql-15/bin/pg_ctl start -D /data/pgsqldata
创建主从同步repl用户
创建数据库用户repl
su - postgres
psql
create role repl with login replication;
设置密码：
postgres=# SET password_encryption = 'scram-sha-256';
postgres=# \password repl
Enter new password for user "repl":
Enter it again:
postgres=# \password postgres
Enter new password for user "postgres":
Enter it again:
postgres=#
允许远程连接到主库
允许从库访问当前主库
# su - postgres
vi /data/pgsqldata/pg_hba.conf #添加修改
#添加# TYPE DATABASE USER ADDRESS METHOD
host all all samenet scram-sha-256
host replication all samenet scram-sha-256
重新加载pg配置
$ /usr/pgsql-15/bin/pg_ctl reload -D /data/pgsqldata
server signaled远程登录验证
[root@node206 ~]# psql -h node203 -U postgres
Password for user postgres:
psql (15.5)
Type "help" for help.postgres=# select inet_server_addr();
inet_server_addr
------------------
192.168.56.203
(1 row)postgres=# \! hostname
node206
postgres=#创建一个数据库和表
create database db1;
\c db1;
create table t1 (id int,name varchar(20));
insert into t1 values (1,'yaya'),(2,'mini');
