To install OpenStack on CentOS 8 using yum, you can follow these steps:

1. Update your system:

sudo yum update -y

2. Enable the OpenStack repository:

sudo yum install -y centos-release-openstack-train

3. Install the OpenStack packages:

sudo yum install -y openstack-packstack

4. Generate the answer file for Packstack:

sudo packstack --gen-answer-file=~/openstack-answers.txt

5. Edit the answer file to customize your OpenStack installation:

sudo vi ~/openstack-answers.txt

You can modify parameters like CONFIG_CONTROLLER_HOST, CONFIG_COMPUTE_HOSTS, CONFIG_NETWORK_HOSTS, etc. to match your environment.

6. Install OpenStack using Packstack and the answer file:

sudo packstack --answer-file=~/openstack-answers.txt

This command will install and configure all the necessary OpenStack services based on your answer file.

Please note that OpenStack is a complex system and may require additional configuration and setup depending on your specific use case. It is recommended to consult the official OpenStack documentation for detailed instructions and best practices.