Postgres as a Service
Deploy a Managed Postgres Cluster in Minutes! Enterprise-ready and Oracle compatible.
2.2 PrerequisitesFailover Manager sends notification emails to the email address specified in the cluster properties file. An SMTP server must be running on each node of the Failover Manager scenario. For more information about using an SMTP server, visit:Failover Manager requires that PostgreSQL streaming replication be configured between the Master node and the Standby node or nodes. Failover Manager does not support other types of replication. For more information about streaming replication, see Appendix A - Configuring Streaming Replication.Please note that Failover Manager does not support automatic reconfiguration of the standby databases after a failover if you use replication slots to manage your WAL segments. If you use replication slots, you should set the auto.reconfigure parameter to false, and manually reconfigure the standby servers in the event of a failover.You must modify the pg_hba.conf file on the Master and Standby nodes, adding entries that allow communication between the all of the nodes in the cluster. The following example demonstrates entries that might be made to the pg_hba.conf file on the Master node:# access for itself
host fmdb efm 127.0.0.1/32 md5
# access for standby
host fmdb efm 192.168.27.1/32 md5
# access for witness
host fmdb efm 192.168.27.34/32 md5efm specifies the name of a valid database user.fmdb specifies the name of a database to which the efm user may connect.For more information about the properties file, see .By default, the pg_hba.conf file resides in the data directory, under your Postgres installation. After modifying the pg_hba.conf file, you must reload the configuration file on each node for the changes to take effect. You can use the following command:# /etc/init.d/ppas-9.x reloadWhere x specifies the Postgres version.You should disable autostart behavior for all of the database servers that are part of a Failover Manager cluster. If a Master node reboots, Failover Manager may detect the database is down on the Master node and promote a Standby node to the role of Master. If this happens, the Failover Manager agent on the Master node will not get a chance to write the recovery.conf file; the rebooted Master node will return to the cluster as a second Master node.When a Standby node is promoted to Master, the autostart behavior of the standby node is preserved. Disable autostart on Standby nodes to prevent the behavior from inadvertently being propagated to the Master node.If a Linux firewall (i.e. iptables) is enabled on the host of a Failover Manager node, you may need to add rules to the firewall configuration that allow tcp communication between the Failover Manager processes in the cluster. For example:The command shown above opens a small range of ports (7800 through 7810). Failover Manager will connect via the port that corresponds to the port specified in the cluster properties file.Before using Failover Manager, you must first install Java (version 1.6 or later). You can use the Yum package manager to install Java. Open a terminal window, assume superuser privileges, and enter:The database user specified in the ppcd.properties file must have sufficient privileges to invoke the following functions on behalf of Failover Manager:For detailed information about each of these functions, please see the PostgreSQL core documentation, available at: