3.6 Preparing a Master Node

A master node is a host from which you deploy Oracle OpenStack for Oracle Linux to the target nodes using the kollacli deploy command.

Typically, you use a controller node as a master node. You should prepare the node as described in Section 3.4, “Preparing Oracle Linux Nodes” before performing the following steps.

If you prefer, you can use a separate host. See Section 3.1, “System Requirements”, for the minimum requirements for a separate host, and you should prepare the node as described in Section 3.4, “Preparing Oracle Linux Nodes” before performing the following steps.

You should only configure a single node as a master node. In order to recover from a failure, you should ensure that you have backups of the /etc/kolla and /usr/share/kolla directories.

To prepare a master node:

Install the OpenStack Kolla CLI (kollacli).
If you are preparing a master node for a new OpenStack deployment:
```
# yum install openstack-kollacli
```
If you are updating a master node for a new release of Oracle OpenStack for Oracle Linux:
```
# yum update openstack-kollacli
```
When you install the openstack-kollacli package, the following operations are performed on the node:
- Create the kolla user.
  The kolla user is the Ansible SSH user and is used to deploy OpenStack services to nodes. The user's home directory is set to /usr/share/kolla.
- Create SSH keys for the kolla user.
  The SSH keys are created in the kolla user's home directory. The public key is copied to /etc/kolla/kollacli/id_rsa.pub on the node.
- Create the /etc/sudoers.d/kolla sudoers configuration file.
  The settings in this file enable the kolla user to run commands, such as ansible and ansible-playbook, as root without prompting for a password.
- Create the kolla group.
  The kolla group is for the users that run the kollacli command.
Add a user to the kolla group.
To add an existing user to the kolla group:
```
# usermod -aG kolla username
```
The user must log out and in again for the group setting to take effect.
Important
For security reasons, always run kollacli commands as this user. Never use root or the kolla user.