Creating a Failover Manager Cluster¶
EDB Postgres Failover Manager (Failover Manager) is a high-availability module from EnterpriseDB that enables a Postgres Master node to automatically failover to a Standby node in the event of a software or hardware failure on the Master.
This quick start guide describes configuring a Failover Manager cluster in a test environment. You should read and understand the EDB Failover Manager User’s Guide before configuring Failover Manager for a production deployment.
You must perform some basic installation and configuration steps before performing this tutorial:
You must install and initialize a database server on one master and one or two standby nodes; for information about installing Advanced Server, visit:
Postgres streaming replication must be configured and running between the master and standby nodes. For detailed information about configuring streaming replication, visit:
You must also install Failover Manager on each master and standby node. During Advanced Server installation, you configured an EnterpriseDB repository on each database host. You can use the EnterpriseDB repository and the
yum installcommand to install Failover Manager on each node of the cluster:
yum install edb-efm310
During the installation process, the installer will create a user named
efm that has sufficient privileges to invoke scripts that control the Failover Manager service for clusters owned by
postgres. The example that follows creates a cluster named
Start the configuration process on a master or standby node. Then, copy the configuration files to other nodes to save time.
Step 1: Create Working Configuration Files
Copy the provided sample files to create EFM configuration files, and correct the ownership:
cd /etc/edb/efm-3.10 cp efm.properties.in efm.properties cp efm.nodes.in efm.nodes chown efm:efm efm.properties chown efm:efm efm.nodes
Step 2: Create an Encrypted Password
Create the encrypted password needed for the properties file:
/usr/edb/efm-3.10/bin/efm encrypt efm
Follow the onscreen instructions to produce the encrypted version of your database password.
Step 3: Update the efm.properties File
<cluster_name>.properties file (efm.properties file in this example) contains parameters that specify connection properties and behaviors for your Failover Manager cluster. Modifications to property settings are applied when Failover Manager starts.
The properties mentioned in this tutorial are the minimal properties required to configure a Failover Manager cluster. If you are configuring a production system, please review the EDB Failover Manager Guide for detailed information about Failover Manager options.
Provide values for the following properties on all cluster nodes:
||The name of the database user.|
||The encrypted password of the database user.|
||The port monitored by the database.|
||The name of the database.|
||The owner of the
||The name of the database service (used to restart the server). Required only if the database is running as a service.|
||The path to the
||An email address at which to receive email notifications (notification text is also in the agent log file).|
||The local address of the node and the port to use for EFM. The format is:
||If you are running on a network without Internet access, set
||On a test cluster, set to
||On a test cluster, set to
Step 4: Update the efm.nodes File
<cluster_name>.nodes file (efm.nodes file in this example) is read at startup to tell an agent how to find the rest of the cluster or, in the case of the first node started, can be used to simplify authorization of subsequent nodes. Add the addresses and ports of each node in the cluster to this file. One node will act as the membership coordinator; the list should include at least the membership coordinator’s address. For example:
Please note that the Failover Manager agent will not verify the content of the
efm.nodes file; the agent expects that some of the addresses in the file cannot be reached (e.g. that another agent hasn’t been started yet).
Step 5: Configure the Other Nodes
efm.nodes files to the
/etc/edb/efm-3.10 directory on the other nodes in your sample cluster. After copying the files, change the file ownership so the files are owned by
efm.properties file can be the same on every node, except for the following properties:
- Modify the
bind.addressproperty to use the node’s local address.
trueif the node is a witness node. If the node is a witness node, the properties relating to a local database installation will be ignored.
Step 6: Start the EFM Cluster
On any node, start the Failover Manager agent. The agent is named
efm-3.10; you can use your platform-specific service command to control the service. For example, on a CentOS/RHEL 7.x or CentOS/RHEL 8.x host use the command:
systemctl start efm-3.10
On a a CentOS or RHEL 6.x host use the command:
service efm-3.10 start
After the agent starts, run the following command to see the status of
the single-node cluster. You should see the addresses of the other nodes
Allowed node host list.
/usr/edb/efm-3.10/bin/efm cluster-status efm
Start the agent on the other nodes. Run the
efm cluster-status efm command on any node to see the cluster status.
If any agent fails to start, see the startup log for information about what went wrong:
Performing a Switchover
If the cluster status output shows that the master and standby(s) are in sync, you can perform a switchover with the following command:
/usr/edb/efm-3.10/bin/efm promote efm -switchover
The command will promote a standby and reconfigure the master database as a new standby in the cluster. To switch back, run the command again.
For quick access to online help, you can invoke the following command: