PostgreSQL如何在Debian上实现高可用性

在Debian上实现PostgreSQL的高可用性，可以采用多种方法。以下是一些常见的解决方案：

1. 使用Patroni

Patroni是一个用于管理PostgreSQL高可用性的工具，它基于Raft共识算法。

安装Patroni

sudo apt-get update
sudo apt-get install python3-pip
sudo pip3 install patroni[etcd]

配置Patroni

创建一个Patroni配置文件/etc/patroni.yml，示例配置如下：

scope: postgres
name: postgres_master
namespace: /db/
restapi:
  listen: 0.0.0.0:8008
  connect_address: 127.0.0.1:8008
etcd:
  host: 127.0.0.1:2379
  ttl: 60
  loop_wait: 10
  retry_timeout: 10
  maximum_lag_on_failover: 1048576
  postgresql:
    use_pg_rewind: true
    use_slots: true
    parameters:
      wal_level: replica
      max_connections: 100
      hot_standby: on
      synchronous_commit: off
      synchronous_standby_names: '*'
      wal_keep_segments: 8
      max_wal_senders: 4
      wal_sender_timeout: 60
      max_replication_slots: 4
      track_commit_timestamp: on
      hot_standby_feedback: on
      synchronous_commit: remote_write
      synchronous_standby_names: 'standby1,standby2'
    data_dir: /var/lib/postgresql/12/main
    pg_hba:
    - host replication replicator 127.0.0.1/32 md5
    - host all all 0.0.0.0/0 md5
bootstrap:
  dcs:
    ttl: 30
    loop_wait: 10
    retry_timeout: 10
    maximum_lag_on_failover: 1048576
    postgresql:
      use_pg_rewind: true
      use_slots: true
      parameters:
        wal_level: replica
        max_connections: 100
        hot_standby: on
        synchronous_commit: off
        synchronous_standby_names: '*'
        wal_keep_segments: 8
        max_wal_senders: 4
        wal_sender_timeout: 60
        max_replication_slots: 4
        track_commit_timestamp: on
        hot_standby_feedback: on
        synchronous_commit: remote_write
        synchronous_standby_names: 'standby1,standby2'
      data_dir: /var/lib/postgresql/12/main
      pg_hba:
      - host replication replicator 127.0.0.1/32 md5
      - host all all 0.0.0.0/0 md5

启动Patroni

sudo patroni /etc/patroni.yml

2. 使用Pgpool-II

Pgpool-II是一个中间件，可以提供负载均衡、故障转移和高可用性。

安装Pgpool-II

sudo apt-get update
sudo apt-get install pgpool2

配置Pgpool-II

编辑/etc/pgpool2/pgpool.conf文件，示例配置如下：

backend_hostname0 = 'primary_host'
backend_port0 = 5432
backend_weight0 = 1

backend_hostname1 = 'standby_host'
backend_port1 = 5432
backend_weight1 = 1

load_balance_mode = on
failover_command = '/usr/lib/postgresql/12/bin/pg_ctl promote -D /var/lib/postgresql/12/main -m fast'
recovery_command = '/usr/lib/postgresql/12/bin/pg_ctl promote -D /var/lib/postgresql/12/main -m fast'

listen_addresses = '*'
port = 9999
auth_method = md5

启动Pgpool-II

sudo systemctl start pgpool2
sudo systemctl enable pgpool2

3. 使用Keepalived

Keepalived可以用于实现虚拟IP地址的高可用性，结合PostgreSQL的主从复制可以实现故障转移。

安装Keepalived

sudo apt-get update
sudo apt-get install keepalived

配置Keepalived

编辑/etc/keepalived/keepalived.conf文件，示例配置如下：

vrrp_instance VI_1 {

    state MASTER
    interface eth0
    virtual_router_id 51
    priority 100
    advert_int 1
    authentication {

        auth_type PASS
        auth_pass 1234
    }

    virtual_ipaddress {

        192.168.1.100
    }

}


virtual_server 192.168.1.100 5432 {

    delay_loop 6
    lb_algo rr
    lb_kind DR
    nat_mask 255.255.255.0
    persistence_timeout 50
    protocol TCP

    real_server 192.168.1.1 5432 {

        weight 1
        TCP_CHECK {

            connect_timeout 10
            connect_port 5432
        }

    }


    real_server 192.168.1.2 5432 {

        weight 1
        TCP_CHECK {

            connect_timeout 10
            connect_port 5432
        }

    }

}
    

启动Keepalived

sudo systemctl start keepalived
sudo systemctl enable keepalived

总结

以上方法各有优缺点，选择哪种方法取决于具体需求和环境。Patroni提供了完整的解决方案，包括故障检测、自动故障转移和数据一致性保证。Pgpool-II适用于需要负载均衡和高可用性的场景。Keepalived结合PostgreSQL的主从复制可以实现简单的故障转移。根据实际情况选择合适的方案进行部署。

声明：本文内容由网友自发贡献，本站不承担相应法律责任。对本内容有异议或投诉，请联系2913721942#qq.com核实处理，我们将尽快回复您，谢谢合作！