Installing and Enabling the Pacemaker and Corosync Service

Install and enable Pacemaker and Corosync on each node in the cluster.

To install and configure Pacemaker and Corosync for an HA cluster, complete the following steps on each cluster node:

Install the pcs and pacemaker software packages, and the required resource and fence agents, for example, by running the following command:
```
sudo dnf install pcs pacemaker resource-agents fence-agents-all
```
Configure the firewall so that the service components can communicate across the network. For example, if you're using firewalld, run the following commands:
```
sudo firewall-cmd --permanent --add-service=high-availability
sudo firewall-cmd --add-service=high-availability
```
The precding commands typically enable the following ports:
- TCP ports 2224 (used by the pcs daemon), 3121 (for Pacemaker Remote nodes), and 21064 (for DLM resources).
- UDP ports 5405 (for Corosync clustering) and 5404 (for Corosync multicast, if configured).
Set a password for the hacluster account so you can use the pcs command to configure and manage the cluster:
```
sudo passwd hacluster
```
Tip:

Set the same same password on each node to avoid authorization issues when running pcs commands on different nodes within the same cluster.
Set the pcsd service to run and to start at boot by running the following command:
```
sudo systemctl enable --now pcsd.service
```

Note:

For running High Availability Clustering in the cloud, see the following documents: