Chapter 6. Performing a remote RHEL installation using VNC

This section describes how to install RHEL remotely using VNC.

6.1. Performing a remote RHEL installation by using VNC

This section describes how to perform a remote RHEL installation using Virtual Network Computing (VNC).

6.1.1. Overview

The graphical user interface is the recommended method of installing RHEL when you boot the system from a CD, DVD, or USB flash drive, or from a network using PXE. However, many enterprise systems, for example, IBM Power Systems and 64-bit IBM Z, are located in remote data center environments that are run autonomously and are not connected to a display, keyboard, and mouse. These systems are often referred to as headless systems and they are typically controlled over a network connection. The RHEL installation program includes a Virtual Network Computing (VNC) installation that runs the graphical installation on the target machine, but control of the graphical installation is handled by another system on the network. The RHEL installation program offers two VNC installation modes: Direct and Connect. Once a connection is established, the two modes do not differ. The mode you select depends on your environment.

Direct mode
In Direct mode, the RHEL installation program is configured to start on the target system and wait for a VNC viewer that is installed on another system before proceeding. As part of the Direct mode installation, the IP address and port are displayed on the target system. You can use the VNC viewer to connect to the target system remotely using the IP address and port, and complete the graphical installation.
Connect mode
In Connect mode, the VNC viewer is started on a remote system in listening mode. The VNC viewer waits for an incoming connection from the target system on a specified port. When the RHEL installation program starts on the target system, the system host name and port number are provided by using a boot option or a Kickstart command. The installation program then establishes a connection with the listening VNC viewer using the specified system host name and port number. To use Connect mode, the system with the listening VNC viewer must be able to accept incoming network connections.

6.1.2. Considerations

Consider the following items when performing a remote RHEL installation using VNC:

  • VNC client application: A VNC client application is required to perform both a VNC Direct and Connect installation. VNC client applications are available in the repositories of most Linux distributions, and free VNC client applications are also available for other operating systems such as Windows. The following VNC client applications are available in RHEL:

    • tigervnc is independent of your desktop environment and is installed as part of the tigervnc package.
    • vinagre is part of the GNOME desktop environment and is installed as part of the vinagre package.
Note

A VNC server is included in the installation program and does not need to be installed.

  • Network and firewall:

    • If the target system is not allowed inbound connections by a firewall, then you must use Connect mode or disable the firewall. Disabling a firewall can have security implications.
    • If the system that is running the VNC viewer is not allowed incoming connections by a firewall, then you must use Direct mode, or disable the firewall. Disabling a firewall can have security implications. See the Security hardening document for more information about configuring the firewall.
  • Custom Boot Options: You must specify custom boot options to start a VNC installation and the installation instructions might differ depending on your system architecture.
  • VNC in Kickstart installations: You can use VNC-specific commands in Kickstart installations. Using only the vnc command runs a RHEL installation in Direct mode. Additional options are available to set up an installation using Connect mode.

6.1.3. Performing a remote RHEL installation in VNC Direct mode

Use this procedure to perform a remote RHEL installation in VNC Direct mode. Direct mode expects the VNC viewer to initiate a connection to the target system that is being installed with RHEL. In this procedure, the system with the VNC viewer is called the remote system. You are prompted by the RHEL installation program to initiate the connection from the VNC viewer on the remote system to the target system.

Note

This procedure uses TigerVNC as the VNC viewer. Specific instructions for other viewers might differ, but the general principles apply.

Prerequisites

  • You have installed a VNC viewer on a remote system as a root user.
  • You have set up a network boot server and booted the installation on the target system.

Procedure

  1. From the RHEL boot menu on the target system, press the Tab key on your keyboard to edit the boot options.

  2. Append the inst.vnc option to the end of the command line.

    1. If you want to restrict VNC access to the system that is being installed, add the inst.vncpassword=PASSWORD boot option to the end of the command line. Replace PASSWORD with the password you want to use for the installation. The VNC password must be between 6 and 8 characters long.

      Important

      Use a temporary password for the inst.vncpassword= option. It should not be an existing or root password.

  3. Press Enter to start the installation. The target system initializes the installation program and starts the necessary services. When the system is ready, a message is displayed providing the IP address and port number of the system.
  4. Open the VNC viewer on the remote system.
  5. Enter the IP address and the port number into the VNC server field.
  6. Click Connect.
  7. Enter the VNC password and click OK. A new window opens with the VNC connection established, displaying the RHEL installation menu. From this window, you can install RHEL on the target system using the graphical user interface.

6.1.4. Performing a remote RHEL installation in VNC Connect mode

Use this procedure to perform a remote RHEL installation in VNC Connect mode. In Connect mode, the target system that is being installed with RHEL initiates a connect to the VNC viewer that is installed on another system. In this procedure, the system with the VNC viewer is called the remote system.

Note

This procedure uses TigerVNC as the VNC viewer. Specific instructions for other viewers might differ, but the general principles apply.

Prerequisites

  • You have installed a VNC viewer on a remote system as a root user.
  • You have set up a network boot server to start the installation on the target system.
  • You have configured the target system to use the boot options for a VNC Connect installation.
  • You have verified that the remote system with the VNC viewer is configured to accept an incoming connection on the required port. Verification is dependent on your network and system configuration. For more information, see Security hardening and Securing networks.

Procedure

  1. Start the VNC viewer on the remote system in listening mode by running the following command: 

    $ vncviewer -listen PORT
  2. Replace PORT with the port number used for the connection.

  3. The terminal displays a message indicating that it is waiting for an incoming connection from the target system. 

    TigerVNC Viewer 64-bit v1.8.0
Built on: 2017-10-12 09:20
Copyright (C) 1999-2017 TigerVNC Team and many others (see README.txt)
See http://www.tigervnc.org for information about TigerVNC.

Thu Jun 27 11:30:57 2019
 main:        Listening on port 5500
  4. Boot the target system from the network.
  5. From the RHEL boot menu on the target system, press the Tab key on your keyboard to edit the boot options.
  6. Append the inst.vnc inst.vncconnect=HOST:PORT option to the end of the command line.
  7. Replace HOST with the IP address of the remote system that is running the listening VNC viewer, and PORT with the port number that the VNC viewer is listening on.
  8. Press Enter to start the installation. The system initializes the installation program and starts the necessary services. When the initialization process is finished, the installation program attempts to connect to the IP address and port provided.
  9. When the connection is successful, a new window opens with the VNC connection established, displaying the RHEL installation menu. From this window, you can install RHEL on the target system using the graphical user interface.