iptables

For Ambari to communicate during configuration with the nodes it deploys and manages, certain ports must be open and available.

The easiest way to do this is to temporarily disable iptables, as follows:

RHEL/CentOS 7

sudo systemctl disable iptables
sudo systemctl stop iptables

RHEL/CentOS/RockyLinux 8

sudo systemctl disable iptables
sudo systemctl stop iptables

Ubuntu 22.04

sudo ufw disable
sudo iptables -X
sudo iptables -t nat -F
sudo iptables -t nat -X
sudo iptables -t mangle -F
sudo iptables -t mangle -X
sudo iptables -P INPUT ACCEPT
sudo iptables -P FORWARD ACCEPT
sudo iptables -P OUTPUT ACCEPT

You can restart iptables once configuration is complete. If your environment's security protocols prevent iptables from being disabled, you can continue with iptables enabled, if all required ports are open and available.

Ambari checks if iptables is running during the Ambari server configuration process. If iptables is running, a warning is displayed, reminding you to check that the required ports are open and available. The Host Confirmation step of the Cluster Installation Wizard also issues a warning for each host on which iptables is running.