Virtual IP Configuration for PostgreSQL (OEL8)

Follow the steps below to configure a secondary Virtual IP (VIP) interface for PostgreSQL on Oracle Enterprise Linux 8:

1. Identify Network Interface

Check existing interface names:

ip addr
# or legacy: ifconfig -a

2. Create Virtual Interface Configuration

Copy your primary interface configuration file:

cd /etc/sysconfig/network-scripts
cp ifcfg-ens192 ifcfg-ens192:1

3. Edit Virtual Interface File

Edit ifcfg-ens192:1 and configure the new IP:

DEVICE=ens192:1
NAME=ens192:1
IPADDR=<new_virtual_ip_address>
ONBOOT=yes

4. Update postgresql.conf Listen Address

Allow PostgreSQL to listen on the new virtual IP:

# /var/lib/pgsql/14/data/postgresql.conf
listen_addresses = '<new_virtual_ip_address>,localhost'

5. Update Systemd Service Unit

Ensure PostgreSQL only starts after the network interfaces are completely online:

# /usr/lib/systemd/system/postgresql-14.service
[Unit]
Wants=network-online.target
After=network-online.target

6. Apply & Verify

Reload the systemd daemon and restart the network and database services:

systemctl daemon-reload
systemctl restart NetworkManager
systemctl restart postgresql-14

Verify that the virtual IP is active and reachable with ip addr show dev ens192.