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Installing the Host OS on the Cluster Server


Use this procedure to install the Atomic Host OS onto a bare metal server. The Atomic Host OS is the required operating system for the cluster servers.

  1. Download the Atomic Host Installer ISO from the CentOS Atomic Host download site.

    Go to and select the installable ISO image for the release specified in Cluster Server Requirements.

  2. Create a DVD or USB drive with that ISO image. You will need to use the appropriate disk imaging tool for the operating system on the machine on which you are creating the drive. You cannot simply copy the image onto the DVD or USB drive.
  3. Boot up the target machine with the DVD. You might need to change the BIOS boot-up sequence to boot from the DVD or USB drive.
  4. Follow the setup screens to set up Linux as you normally do:
    • Configure the language support and keyboard settings.

    • Specify the installation destination (hard drive) where you want to install the OS.

    • Configure the networking parameters and hostname and enable the Ethernet interface. All cluster members must be on the same subnet and all cluster members must be able to reach the devices in the managed network.

      • Set the IPv4 address, the IPv4 default gateway, and the IPv4 Domain Name Server (DNS). This is required even if you are performing an IPv6 proNX Optical Director installation later.

      • Optionally, set the IPv6 address, the IPv6 default gateway, and the IPv6 Domain Name Server (DNS). This is only required if you are performing an IPv6 proNX Optical Director installation later. IPv6 proNX Optical Director installation is supported starting in release 18.4.

      • Set the hostname. It is required that you set a valid and unique static hostname for each server. A valid hostname consists of a host portion followed by a dot followed by a domain name (for example, server1.mydomain). Ensure the hostname is resolvable (that is, remember to add a DNS entry so that the hostname can resolve to the configured IP address).

      • Enable the Ethernet interface.

    • Configure the date and time settings (including NTP server settings).


    Do not override or change any partitioning settings. The proNX Optical Director software installation script automatically configures the partitioning later.

  5. Configure the root password.
  6. Reboot the machine when prompted.
  7. After the machine reboots, log in as root.
  8. Verify that the machine has successfully synchronized with the NTP server(s) that you specified during OS installation. By default, the machine uses chrony for NTP server synchronization.

    For example:

    # chronyc sources -v

    If you forgot to specify the NTP server(s) during OS installation, edit and specify the NTP server(s) in the /etc/chrony.conf file. To make the changes take effect, stop and start the chronyd service (systemctl stop chronyd.service followed by systemctl start chronyd.service).

    Before proceeding to the next step, ensure at least one NTP server is shown in “*” state.

  9. Optionally, set up a user that the control machine installation script can use to log in to this machine. You can delete this user once the installation is complete. You can skip this step if you choose to let the control machine installation script log in as root.

    For example, this sets up a user called deploy.

    Give this user no-password sudo access (that is, sudo access where no password is prompted for).

    To do this, edit the sudoers file:

    Add the following line to the file for the deploy user:

    This line specifies that the deploy user is allowed sudo access and that the deploy user is not prompted for a password when running sudo commands.

This cluster server is now ready for proNX Optical Director software installation. Repeat this procedure on all servers in the cluster. Ensure that the root password (and the deploy username and password if applicable) is the same on all servers.