pacemaker+corosync 搭建一主两从PG集群

在搭建一主两从的PG集群时，可以使用Pacemaker和Corosync。以下是一个简化的步骤和配置示例：

1. 安装Pacemaker和Corosync：

sudo apt-get install pacemaker corosync

2. 配置PostgreSQL，确保数据库已经初始化并可以正常启动。
3. 配置Corosync，编辑/etc/corosync/corosync.conf，例子如下：

totem {
    version: 2
    secauth: off
    cluster_name: pgcluster
    transport: udpu
}
 
logging {
    fileline: off
    to_stderr: no
    to_logfile: yes
    logfile: /var/log/corosync.log
    to_syslog: yes
    syslog_facility: daemon
    debug: off
    timestamp: on
    logger_subsys {
        subsys: AMF
        debug: off
    }
}
 
amf {
    mode: disabled
}
 
service {
    ver: 0
    name: pacemaker
}

4. 启动并激活Corosync服务：

sudo systemctl start corosync
sudo systemctl enable corosync

5. 配置Pacemaker，添加PostgreSQL资源。
6. 启动并激活Pacemaker服务：

sudo systemctl start pacemaker
sudo systemctl enable pacemaker

7. 使用pcs工具添加一主两从的PostgreSQL资源。例子如下：

pcs resource create pg_master ocf:heartbeat:pg \
    op start timeout=60s \
    op stop timeout=60s \
    op monitor interval=20s timeout=60s \
    --master \
    --clone \
    --order=2000 \
    --failure-action=promote \
    --resource-stickiness=100
 
pcs resource create pg_slave_1 ocf:heartbeat:pg \
    op start timeout=60s \
    op stop timeout=60s \
    op monitor interval=20s timeout=60s \
    --slave \
    --clone \
    --order=2000 \
    --failure-action=promote \
    --resource-stickiness=100
 
pcs resource create pg_slave_2 ocf:heartbeat:pg \
    op start timeout=60s \
    op stop timeout=60s \
    op monitor interval=20s timeout=60s \
    --slave \
    --clone \
    --order=2000 \
    --failure-action=promote \
    --resource-stickiness=100
 
pcs constraint colocation add pg_master with pg_slave_1 pg_slave_2
pcs constraint order then pg_slave_1 then pg_slave_2

8. 检查并保存配置：

pcs property set stonith-enabled=false
pcs property set no-quorum-policy=ignore
pcs configure show
pcs cluster setup --name pgcluster --start --quorum=2 pg1 pg2 pg3

9. 将服务添加到集群：

pcs resource enable pg_master
pcs resource enable pg_slave