- Overview
- Requirements
- Installation
- Upgrade
- Troubleshooting
- Installation issue with port 53
- Failed initial Redis installation
- Firewall blocking HTTP connections
High Availability Add-on installation guide
Linux reserves port 53 for DNS servers. Sometimes, the installation of High Availability Add-on (HAA) might fail because port 53 is already in use. This happens because HAA includes its own DNS server that needs port 53 open.
systemd-resolved,
while on RHEL, it is likely to be dnsmasq.
The following sections provide instructions on how to deactivate the DNS servers.
systemd-resolved service, refer to the Redis documentation.
dnsmasq service, follow these steps:
-
If the service is running, stop it:
sudo systemctl stop dnsmasqsudo systemctl stop dnsmasq -
After stopping the service, you must disable it to prevent it from starting automatically on system reboot:
sudo systemctl disable dnsmasqsudo systemctl disable dnsmasq -
Mask the service to prevent it from being started manually or by any other service:
sudo systemctl mask dnsmasqsudo systemctl mask dnsmasqWhen the service is masked, it cannot be started, even if another service or script tries to initiate it.
-
Verify that the service is no longer active and does not start on the following system reboot:
sudo systemctl status dnsmasqsudo systemctl status dnsmasq
