Chapter 2. Getting started with virtualization To start using virtualization in RHEL 8 , follow the steps below. The default method for this is using the command line (CLI), but for user convenience, some of the steps can be completed in the web console GUI . Enable the virtualization module and install the virtualization packages - see Enabling virtualization . Create a virtual machine (VM): For CLI, see Creating virtual machines by using the command line . For GUI, see Creating virtual machines and installing guest operating systems by using the web console . Start the VM: For CLI, see Starting a virtual machine by using the command line . For GUI, see Starting virtual machines by using the web console . Connect to the VM: For CLI, see Connecting to a virtual machine by using SSH or Opening a virtual machine graphical console by using Virt Viewer . For GUI, see Interacting with virtual machines by using the web console . Note The web console currently provides only a subset of VM management functions, so using the command line is recommended for advanced use of virtualization in RHEL 8. 2.1. Enabling virtualization To use virtualization in RHEL 8, you must enable the virtualization module, install virtualization packages, and ensure your system is configured to host virtual machines (VMs). Prerequisites RHEL 8 is installed and registered on your host machine. Your system meets the following hardware requirements to work as a virtualization host: The following minimum system resources are available: 6 GB free disk space for the host, plus another 6 GB for each intended VM. 2 GB of RAM for the host, plus another 2 GB for each intended VM. 4 CPUs on the host. VMs can generally run with a single assigned vCPU, but Red Hat recommends assigning 2 or more vCPUs per VM to avoid VMs becoming unresponsive during high load. The architecture of your host machine supports KVM virtualization . Notably, RHEL 8 does not support virtualization on the 64-bit ARM architecture (ARM 64). The procedure below applies to the AMD64 and Intel 64 architecture (x86_64). To enable virtualization on a host with a different supported architecture, see one of the following sections: Enabling virtualization on IBM POWER Enabling virtualization on IBM Z Procedure Install the packages in the RHEL 8 virtualization module: Install the virt-install and virt-viewer packages: Start the libvirtd service: Verification Verify that your system is prepared to be a virtualization host: Review the return values of virt-host-validate checks and take appropriate actions: If all virt-host-validate checks return the PASS value, your system is prepared for creating VMs . If any of the checks return a FAIL value, follow the displayed instructions to fix the problem. If any of the checks return a WARN value, consider following the displayed instructions to improve virtualization capabilities Troubleshooting If KVM virtualization is not supported by your host CPU, virt-host-validate generates the following output: However, VMs on such a host system will fail to boot, rather than have performance problems. To work around this, you can change the <domain type> value in the XML configuration of the VM to qemu . Note, however, that Red Hat does not support VMs that use the qemu domain type, and setting this is highly discouraged in production environments. 2.2. Creating virtual machines To create a virtual machine (VM) in RHEL 8, use the command line or the RHEL 8 web console . 2.2.1. Creating virtual machines by using the command line To create a virtual machine (VM) on your RHEL 8 by using the command line, use the virt-install utility. Prerequisites Virtualization is enabled on your host system. You have a sufficient amount of system resources to allocate to your VMs, such as disk space, RAM, or CPUs. The recommended values may vary significantly depending on the intended tasks and workload of the VMs. An operating system (OS) installation source is available locally or on a network. This can be one of the following: An ISO image of an installation medium A disk image of an existing VM installation Warning Installing from a host CD-ROM or DVD-ROM device is not possible in RHEL 8. If you select a CD-ROM or DVD-ROM as the installation source when using any VM installation method available in RHEL 8, the installation will fail. For more information, see the Red Hat Knowledgebase solution RHEL 7 or higher can't install guest OS from CD/DVD-ROM . Also note that Red Hat provides support only for a limited set of guest operating systems . Optional: A Kickstart file can be provided for faster and easier configuration of the installation. Procedure To create a VM and start its OS installation, use the virt-install command, along with the following mandatory arguments: --name : the name of the new machine --memory : the amount of allocated memory --vcpus : the number of allocated virtual CPUs --disk : the type and size of the allocated storage --cdrom or --location : the type and location of the OS installation source Based on the chosen installation method, the necessary options and values can vary. See the commands below for examples: Note The listed commands use the VNC remote display protocol instead of the default SPICE protocol. VNC currently does not have some of the features that SPICE does, but is fully supported on RHEL 9. As a result, VMs that use VNC will not stop working if you migrate your host to RHEL 9. For more information, see Considerations in adopting RHEL 9 . The following command creates a VM named demo-guest1 that installs the Windows 10 OS from an ISO image locally stored in the /home/username/Downloads/Win10install.iso file. This VM is also allocated with 2048 MiB of RAM and 2 vCPUs, and an 80 GiB qcow2 virtual disk is automatically configured for the VM. The following command creates a VM named demo-guest2 that uses the /home/username/Downloads/rhel8.iso image to run a RHEL 8 OS from a live CD. No disk space is assigned to this VM, so changes made during the session will not be preserved. In addition, the VM is allocated with 4096 MiB of RAM and 4 vCPUs. The following command creates a RHEL 8 VM named demo-guest3 that connects to an existing disk image, /home/username/backup/disk.qcow2 . This is similar to physically moving a hard drive between machines, so the OS and data available to demo-guest3 are determined by how the image was handled previously. In addition, this VM is allocated with 2048 MiB of RAM and 2 vCPUs. Note that the --os-variant option is highly recommended when importing a disk image. If it is not provided, the performance of the created VM will be negatively affected. The following command creates a VM named demo-guest4 that installs from the http://example.com/OS-install URL. For the installation to start successfully, the URL must contain a working OS installation tree. In addition, the OS is automatically configured by using the /home/username/ks.cfg kickstart file. This VM is also allocated with 2048 MiB of RAM, 2 vCPUs, and a 160 GiB qcow2 virtual disk. The following command creates a VM named demo-guest5 that installs from a RHEL8.iso image file in text-only mode, without graphics. It connects the guest console to the serial console. The VM has 16384 MiB of memory, 16 vCPUs, and 280 GiB disk. This kind of installation is useful when connecting to a host over a slow network link. The following command creates a VM named demo-guest6 , which has the same configuration as demo-guest5, but resides on the 192.0.2.1 remote host. Verification If the VM is created successfully, a virt-viewer window opens with a graphical console of the VM and starts the guest OS installation. Troubleshooting If virt-install fails with a cannot find default network error: Ensure that the libvirt-daemon-config-network package is installed: Verify that the libvirt default network is active and configured to start automatically: If it is not, activate the default network and set it to auto-start: If activating the default network fails with the following error, the libvirt-daemon-config-network package has not been installed correctly. To fix this, re-install libvirt-daemon-config-network : If activating the default network fails with an error similar to the following, a conflict has occurred between the default network's subnet and an existing interface on the host. To fix this, use the virsh net-edit default command and change the 192.0.2.* values in the configuration to a subnet not already in use on the host. Additional resources virt-install (1) man page on your system Creating virtual machines and installing guest operating systems by using the web console Cloning virtual machines 2.2.2. Creating virtual machines and installing guest operating systems by using the web console To manage virtual machines (VMs) in a GUI on a RHEL 8 host, use the web console. The following sections provide information about how to use the RHEL 8 web console to create VMs and install guest operating systems on them. Important VMs created by using the web console currently use the SPICE remote desktop protocol by default. However, SPICE is unsupported on RHEL 9, so if you upgrade your host to RHEL 9, the VM will stop working. For more information, see Considerations in adopting RHEL 9 . To create a VM that uses the VNC protocol, which will work correctly on RHEL 9, use the command line . 2.2.2.1. Creating virtual machines by using the web console To create a virtual machine (VM) on a host machine to which your RHEL 8 web console is connected, use the instructions below. Prerequisites You have installed the RHEL 8 web console. You have enabled the cockpit service. Your user account is allowed to log in to the web console. For instructions, see Installing and enabling the web console . Virtualization is enabled on your host system . The web console VM plug-in is installed on your host system . You have a sufficient amount of system resources to allocate to your VMs, such as disk space, RAM, or CPUs. The recommended values might vary significantly depending on the intended tasks and workload of the VMs. Procedure In the Virtual Machines interface of the web console, click Create VM . The Create new virtual machine dialog appears. Enter the basic configuration of the VM you want to create. Name - The name of the VM. Connection - The level of privileges granted to the session. For more details, expand the associated dialog box in the web console. Installation type - The installation can use a local installation medium, a URL, a PXE network boot, a cloud base image, or download an operating system from a limited set of operating systems. Operating system - The guest operating system running on the VM. Note that Red Hat provides support only for a limited set of guest operating systems . Note To download and install Red Hat Enterprise Linux directly from web console, you must add an offline token in the Offline token field. Storage - The type of storage. Storage Limit - The amount of storage space. Memory - The amount of memory. Create the VM: If you want the VM to automatically install the operating system, click Create and run . If you want to edit the VM before the operating system is installed, click Create and edit . steps Installing guest operating systems by using the web console Additional resources Creating virtual machines by using the command line 2.2.2.2. Creating virtual machines by importing disk images by using the web console You can create a virtual machine (VM) by importing a disk image of an existing VM installation in the RHEL 8 web console. Prerequisites You have installed the RHEL 8 web console. You have enabled the cockpit service. Your user account is allowed to log in to the web console. For instructions, see Installing and enabling the web console . The web console VM plug-in is installed on your system . You have a sufficient amount of system resources to allocate to your VMs, such as disk space, RAM, or CPUs. The recommended values can vary significantly depending on the intended tasks and workload of the VMs. You have downloaded a disk image of an existing VM installation. Procedure In the Virtual Machines interface of the web console, click Import VM . The Import a virtual machine dialog appears. Enter the basic configuration of the VM you want to create: Name - The name of the VM. Disk image - The path to the existing disk image of a VM on the host system. Operating system - The operating system running on a VM disk. Note that Red Hat provides support only for a limited set of guest operating systems . Memory - The amount of memory to allocate for use by the VM. Import the VM: To install the operating system on the VM without additional edits to the VM settings, click Import and run . To edit the VM settings before the installation of the operating system, click Import and edit . 2.2.2.3. Installing guest operating systems by using the web console When a virtual machine (VM) boots for the first time, you must install an operating system on the VM. Note If you click Create and run or Import and run while creating a new VM, the installation routine for the operating system starts automatically when the VM is created. Prerequisites You have installed the RHEL 8 web console. You have enabled the cockpit service. Your user account is allowed to log in to the web console. For instructions, see Installing and enabling the web console . The web console VM plug-in is installed on your host system . Procedure Log in to the RHEL 8 web console. For details, see Logging in to the web console . In the Virtual Machines interface, click the VM on which you want to install a guest OS. A new page opens with basic information about the selected VM and controls for managing various aspects of the VM. Optional: Change the firmware. Note You can change the firmware only if you selected Create and edit or Import and edit while creating a new VM and if the OS is not already installed on the VM. Click the firmware. In the Change Firmware window, select the required firmware. Click Save . Click Install . The installation routine of the operating system runs in the VM console. Troubleshooting If the installation routine fails, delete and recreate the VM before starting the installation again. 2.2.3. Creating virtual machines with cloud image authentication by using the web console By default, distro cloud images have no login accounts. However, by using the RHEL web console, you can now create a virtual machine (VM) and specify the root and user account login credentials, which are then passed to cloud-init. Prerequisites You have installed the RHEL 8 web console. You have enabled the cockpit service. Your user account is allowed to log in to the web console. For instructions, see Installing and enabling the web console . The web console VM plug-in is installed on your system . Virtualization is enabled on your host system. You have a sufficient amount of system resources to allocate to your VMs, such as disk space, RAM, or CPUs. The recommended values may vary significantly depending on the intended tasks and workload of the VMs. Procedure Log in to the RHEL 8 web console. For details, see Logging in to the web console . In the Virtual Machines interface of the web console, click Create VM . The Create new virtual machine dialog appears. In the Name field, enter a name for the VM. On the Details tab, in the Installation type field, select Cloud base image . In the Installation source field, set the path to the image file on your host system. Enter the configuration for the VM that you want to create. Operating system - The VM's operating system. Note that Red Hat provides support only for a limited set of guest operating systems . Storage - The type of storage with which to configure the VM. Storage Limit - The amount of storage space with which to configure the VM. Memory - The amount of memory with which to configure the VM. Click on the Automation tab. Set your cloud authentication credentials. Root password - Enter a root password for your VM. Leave the field blank if you do not wish to set a root password. User login - Enter a cloud-init user login. Leave this field blank if you do not wish to create a user account. User password - Enter a password. Leave this field blank if you do not wish to create a user account. Click Create and run . The VM is created. Additional resources Installing an operating system on a VM 2.3. Starting virtual machines To start a virtual machine (VM) in RHEL 8, you can use the command line or the web console GUI . Prerequisites Before a VM can be started, it must be created and, ideally, also installed with an OS. For instruction to do so, see Creating virtual machines . 2.3.1. Starting a virtual machine by using the command line You can use the command line (CLI) to start a shut-down virtual machine (VM) or restore a saved VM. By using the CLI, you can start both local and remote VMs. Prerequisites An inactive VM that is already defined. The name of the VM. For remote VMs: The IP address of the host where the VM is located. Root access privileges to the host. Procedure For a local VM, use the virsh start utility. For example, the following command starts the demo-guest1 VM. For a VM located on a remote host, use the virsh start utility along with the QEMU+SSH connection to the host. For example, the following command starts the demo-guest1 VM on the 192.0.2.1 host. Additional resources The virsh start --help command Setting up easy access to remote virtualization hosts Starting virtual machines automatically when the host starts 2.3.2. Starting virtual machines by using the web console If a virtual machine (VM) is in the shut off state, you can start it by using the RHEL 8 web console. You can also configure the VM to be started automatically when the host starts. Prerequisites You have installed the RHEL 8 web console. You have enabled the cockpit service. Your user account is allowed to log in to the web console. For instructions, see Installing and enabling the web console . The web console VM plug-in is installed on your system . An inactive VM that is already defined. The name of the VM. Procedure In the Virtual Machines interface, click the VM you want to start. A new page opens with detailed information about the selected VM and controls for shutting down and deleting the VM. Click Run . The VM starts, and you can connect to its console or graphical output . Optional: To configure the VM to start automatically when the host starts, toggle the Autostart checkbox in the Overview section. If you use network interfaces that are not managed by libvirt, you must also make additional changes to the systemd configuration. Otherwise, the affected VMs might fail to start, see starting virtual machines automatically when the host starts . Additional resources Shutting down virtual machines in the web console Restarting virtual machines by using the web console 2.3.3. Starting virtual machines automatically when the host starts When a host with a running virtual machine (VM) restarts, the VM is shut down, and must be started again manually by default. To ensure a VM is active whenever its host is running, you can configure the VM to be started automatically. Prerequisites A created virtual machine Procedure Use the virsh autostart utility to configure the VM to start automatically when the host starts. For example, the following command configures the demo-guest1 VM to start automatically. If you use network interfaces that are not managed by libvirt , you must also make additional changes to the systemd configuration. Otherwise, the affected VMs might fail to start. Note These interfaces include for example: Bridge devices created by NetworkManager Networks configured to use <forward mode='bridge'/> In the systemd configuration directory tree, create a libvirtd.service.d directory if it does not exist yet. Create a 10-network-online.conf systemd unit override file in the previously created directory. The content of this file overrides the default systemd configuration for the libvirtd service. Add the following lines to the 10-network-online.conf file. This configuration change ensures systemd starts the libvirtd service only after the network on the host is ready. Verification View the VM configuration, and check that the autostart option is enabled. For example, the following command displays basic information about the demo-guest1 VM, including the autostart option. If you use network interfaces that are not managed by libvirt, check if the content of the 10-network-online.conf file matches the following output. Additional resources The virsh autostart --help command Starting virtual machines by using the web console . 2.4. Connecting to virtual machines To interact with a virtual machine (VM) in RHEL 8, you need to connect to it by doing one of the following: When using the web console interface, use the Virtual Machines pane in the web console interface. For more information, see Interacting with virtual machines by using the web console . If you need to interact with a VM graphical display without using the web console, use the Virt Viewer application. For details, see Opening a virtual machine graphical console by using Virt Viewer . When a graphical display is not possible or not necessary, use an SSH terminal connection . When the virtual machine is not reachable from your system by using a network, use the virsh console . If the VMs to which you are connecting are on a remote host rather than a local one, you can optionally configure your system for more convenient access to remote hosts . Prerequisites The VMs you want to interact with are installed and started . 2.4.1. Interacting with virtual machines by using the web console To interact with a virtual machine (VM) in the RHEL 8 web console, you need to connect to the VM's console. These include both graphical and serial consoles. To interact with the VM's graphical interface in the web console, use the graphical console . To interact with the VM's graphical interface in a remote viewer, use the graphical console in remote viewers . To interact with the VM's CLI in the web console, use the serial console . 2.4.1.1. Viewing the virtual machine graphical console in the web console By using the virtual machine (VM) console interface, you can view the graphical output of a selected VM in the RHEL 8 web console. Prerequisites You have installed the RHEL 8 web console. You have enabled the cockpit service. Your user account is allowed to log in to the web console. For instructions, see Installing and enabling the web console . The web console VM plug-in is installed on your system . Ensure that both the host and the VM support a graphical interface. Procedure Log in to the RHEL 8 web console. For details, see Logging in to the web console . In the Virtual Machines interface, click the VM whose graphical console you want to view. A new page opens with an Overview and a Console section for the VM. Select VNC console in the console drop down menu. The VNC console appears below the menu in the web interface. The graphical console appears in the web interface. Click Expand You can now interact with the VM console by using the mouse and keyboard in the same manner you interact with a real machine. The display in the VM console reflects the activities being performed on the VM. Note The host on which the web console is running may intercept specific key combinations, such as Ctrl + Alt + Del , preventing them from being sent to the VM. To send such key combinations, click the Send key menu and select the key sequence to send. For example, to send the Ctrl + Alt + Del combination to the VM, click the Send key and select the Ctrl+Alt+Del menu entry. Troubleshooting If clicking in the graphical console does not have any effect, expand the console to full screen. This is a known issue with the mouse cursor offset. Additional resources Viewing the graphical console in a remote viewer by using the web console Viewing the virtual machine serial console in the web console 2.4.1.2. Viewing the graphical console in a remote viewer by using the web console By using the web console interface, you can display the graphical console of a selected virtual machine (VM) in a remote viewer, such as Virt Viewer. Note You can launch Virt Viewer from within the web console. Other VNC and SPICE remote viewers can be launched manually. Prerequisites You have installed the RHEL 8 web console. You have enabled the cockpit service. Your user account is allowed to log in to the web console. For instructions, see Installing and enabling the web console . The web console VM plug-in is installed on your system . Ensure that both the host and the VM support a graphical interface. Before you can view the graphical console in Virt Viewer, you must install Virt Viewer on the machine to which the web console is connected. Click Launch remote viewer . The virt viewer, .vv , file downloads. Open the file to launch Virt Viewer. Note Remote Viewer is available on most operating systems. However, some browser extensions and plug-ins do not allow the web console to open Virt Viewer. Procedure Log in to the RHEL 8 web console. For details, see Logging in to the web console . In the Virtual Machines interface, click the VM whose graphical console you want to view. A new page opens with an Overview and a Console section for the VM. Select Desktop Viewer in the console drop down menu. Click Launch Remote Viewer . The graphical console opens in Virt Viewer. You can interact with the VM console by using the mouse and keyboard in the same manner in which you interact with a real machine. The display in the VM console reflects the activities being performed on the VM. Note The server on which the web console is running can intercept specific key combinations, such as Ctrl + Alt + Del , preventing them from being sent to the VM. To send such key combinations, click the Send key menu and select the key sequence to send. For example, to send the Ctrl + Alt + Del combination to the VM, click the Send key menu and select the Ctrl+Alt+Del menu entry. Troubleshooting If clicking in the graphical console does not have any effect, expand the console to full screen. This is a known issue with the mouse cursor offset. If launching the Remote Viewer in the web console does not work or is not optimal, you can manually connect with any viewer application by using the following protocols: Address - The default address is 127.0.0.1 . You can modify the vnc_listen or the spice_listen parameter in /etc/libvirt/qemu.conf to change it to the host's IP address. SPICE port - 5900 VNC port - 5901 Additional resources Viewing the virtual machine graphical console in the web console Viewing the virtual machine serial console in the web console 2.4.1.3. Viewing the virtual machine serial console in the web console You can view the serial console of a selected virtual machine (VM) in the RHEL 8 web console. This is useful when the host machine or the VM is not configured with a graphical interface. For more information about the serial console, see Opening a virtual machine serial console . Prerequisites You have installed the RHEL 8 web console. You have enabled the cockpit service. Your user account is allowed to log in to the web console. For instructions, see Installing and enabling the web console . The web console VM plug-in is installed on your system . Procedure Log in to the RHEL 8 web console. For details, see Logging in to the web console . In the Virtual Machines pane, click the VM whose serial console you want to view. A new page opens with an Overview and a Console section for the VM. Select Serial console in the console drop down menu. The graphical console appears in the web interface. You can disconnect and reconnect the serial console from the VM. To disconnect the serial console from the VM, click Disconnect . To reconnect the serial console to the VM, click Reconnect . Additional resources Viewing the virtual machine graphical console in the web console Viewing the graphical console in a remote viewer by using the web console 2.4.1.4. Replacing the SPICE remote display protocol with VNC in the web console The SPICE remote display protocol is deprecated in RHEL 8 and will be removed in RHEL 9. If you have a virtual machine (VM) that is configured to use the SPICE protocol, you can replace the SPICE protocol with the VNC protocol by using the web console. However, certain SPICE devices, such as audio and USB passthrough, will be removed from the VM because they do not have a suitable replacement in the VNC protocol. Important By default, RHEL 8 VMs are configured to use the SPICE protocol. These VMs fail to migrate to RHEL 9, unless you switch from SPICE to VNC. Prerequisites The web console VM plug-in is installed on your system . You have an existing VM that is configured to use the SPICE remote display protocol and is already shut-down. Procedure In the Virtual Machines interface of the web console, click the Menu button ... of the VM that is configured to use the SPICE protocol. A drop down menu opens with controls for various VM operations. Click Replace SPICE devices . The Replace SPICE devices dialog opens. Note If you have multiple existing VMs that use the SPICE protocol, they are listed in this dialog. Here, you can select multiple VMs to convert from using SPICE to VNC in a single step. Click Replace . A confirmation of the successful operation appears. 2.4.2. Opening a virtual machine graphical console by using Virt Viewer To connect to a graphical console of a KVM virtual machine (VM) and open it in the Virt Viewer desktop application, follow the procedure below. Prerequisites Your system, as well as the VM you are connecting to, must support graphical displays. If the target VM is located on a remote host, connection and root access privileges to the host are needed. Optional: If the target VM is located on a remote host, set up your libvirt and SSH for more convenient access to remote hosts . Procedure To connect to a local VM, use the following command and replace guest-name with the name of the VM you want to connect to: To connect to a remote VM, use the virt-viewer command with the SSH protocol. For example, the following command connects as root to a VM called guest-name , located on remote system 192.0.2.1. The connection also requires root authentication for 192.0.2.1. Verification If the connection works correctly, the VM display is shown in the Virt Viewer window. You can interact with the VM console by using the mouse and keyboard in the same manner you interact with a real machine. The display in the VM console reflects the activities being performed on the VM. Troubleshooting If clicking in the graphical console does not have any effect, expand the console to full screen. This is a known issue with the mouse cursor offset. Additional resources virt-viewer man page on your system Setting up easy access to remote virtualization hosts Interacting with virtual machines by using the web console 2.4.3. Connecting to a virtual machine by using SSH To interact with the terminal of a virtual machine (VM) by using the SSH connection protocol, follow the procedure below. Prerequisites You have network connection and root access privileges to the target VM. If the target VM is located on a remote host, you also have connection and root access privileges to that host. Your VM network assigns IP addresses by dnsmasq generated by libvirt . This is the case for example in libvirt NAT networks . Notably, if your VM is using one of the following network configurations, you cannot connect to the VM by using SSH: hostdev interfaces Direct interfaces Bridge interaces The libvirt-nss component is installed and enabled on the VM's host. If it is not, do the following: Install the libvirt-nss package: Edit the /etc/nsswitch.conf file and add libvirt_guest to the hosts line: Procedure When connecting to a remote VM, SSH into its physical host first. The following example demonstrates connecting to a host machine 192.0.2.1 by using its root credentials: Use the VM's name and user access credentials to connect to it. For example, the following connects to the testguest1 VM by using its root credentials: Troubleshooting If you do not know the VM's name, you can list all VMs available on the host by using the virsh list --all command: Additional resources Upstream libvirt documentation 2.4.4. Opening a virtual machine serial console By using the virsh console command, it is possible to connect to the serial console of a virtual machine (VM). This is useful when the VM: Does not provide VNC or SPICE protocols, and thus does not offer video display for GUI tools. Does not have a network connection, and thus cannot be interacted with using SSH . Prerequisites The GRUB boot loader on your host must be configured to use serial console. To verify, check that the /etc/default/grub file on your host contains the GRUB_TERMINAL=serial parameter. The VM must have a serial console device configured, such as console type='pty' . To verify, do the following: The VM must have the serial console configured in its kernel command line. To verify this, the cat /proc/cmdline command output on the VM should include console=<console-name> , where <console-name> is architecture-specific: For AMD64 and Intel 64: ttyS0 Note The following commands in this procedure use ttyS0 . If the serial console is not set up properly on a VM, using virsh console to connect to the VM connects you to an unresponsive guest console. However, you can still exit the unresponsive console by using the Ctrl + ] shortcut. To set up serial console on the VM, do the following: On the VM, enable the console=ttyS0 kernel option: Clear the kernel options that might prevent your changes from taking effect. Reboot the VM. The serial-getty@ <console-name> service must be enabled. For example, on AMD64 and Intel 64: Procedure On your host system, use the virsh console command. The following example connects to the guest1 VM, if the libvirt driver supports safe console handling: You can interact with the virsh console in the same way as with a standard command-line interface. Additional resources virsh man page on your system Configuring Serial Console Logs on a VM (video) 2.4.5. Setting up easy access to remote virtualization hosts When managing VMs on a remote host system by using libvirt utilities, it is recommended to use the -c qemu+ssh://root@hostname/system syntax. For example, to use the virsh list command as root on the 192.0.2.1 host: However, you can remove the need to specify the connection details in full by modifying your SSH and libvirt configuration. For example: To enable this improvement, follow the instructions below. Procedure Edit the ~/.ssh/config file with the following details, where host-alias is a shortened name associated with a specific remote host and an alias for root@192.0.2.1, and hosturl is the URL address of the host : Edit the /etc/libvirt/libvirt.conf file with the following details, the example-qemu-host-alias is a host alias that QEMU and libvirt utilities will associate for qemu+ssh://192.0.2.1/system with the intended host example-host-alias : Verification Confirm that you can manage remote VMs by using libvirt-based utilities on the local system with an added -c qemu-host-alias parameter. This automatically performs the commands over SSH on the remote host. For example, verify that the following lists VMs on the 192.0.2.1 remote host, the connection to which was set up as example-qemu-host-alias in the steps: Note In addition to virsh , the -c (or --connect ) option and the remote host access configuration described above can be used by the following utilities: virt-install virt-viewer steps If you want to use libvirt utilities exclusively on a single remote host, you can also set a specific connection as the default target for libvirt-based utilities. However, this is not recommended if you also want to manage VMs on your local host or on different remote hosts. You can edit the /etc/libvirt/libvirt.conf file and set the value of the uri_default parameter to example-qemu-host-alias as a default libvirt target. As a result, all libvirt-based commands will automatically be performed on the specified remote host. When connecting to a remote host, you can avoid providing the root password to the remote system. To do so, use one or more of the following methods: Set up key-based SSH access to the remote host Use SSH connection multiplexing to connect to the remote system Kerberos authentication in Identity Management The -c (or --connect ) option can be used to run the virt-install , virt-viewer , virsh and virt-manager commands on a remote host. 2.4.6. Configuring VNC passwords To manage access to the graphical output of a virtual machine (VM), you can configure a password for the VNC console of the VM. With a VNC password configured on a VM, users of the VMs must enter the password when attempting to view or interact with the VNC graphical console of the VMs, for example by using the virt-viewer utility. Important VNC passwords are not a sufficient measure for ensuring the security of a VM environment. For details, see QEMU documentation on VNC security . In addition, the VNC password is saved in plain text in the configuration of the VM, so for the password to be effective, the user must not be able to display the VM configuration. Prerequisites The VM that you want to protect with a VNC password has VNC graphics configured. To ensure that this is the case, use the virsh dumpxml command as follows: Procedure Open the configuration of the VM that you want to assign a VNC password to. On the <graphics> line of the configuration, add the passwd attribute and the password string. The password must be 8 characters or fewer. Optional: In addition, define a date and time when the password will expire. In this example, the password will expire on February 1st 2025, at 15:30 UTC. Save the configuration. Verification Start the modified VM. Open a graphical console of the VM, for example by using the virt-viewer utility: If the VNC password has been configured properly, a dialogue window appears that requests you to enter the password. 2.5. Shutting down virtual machines To shut down a running virtual machine hosted on RHEL 8, use the command line or the web console GUI . 2.5.1. Shutting down a virtual machine by using the command line Shutting down a virtual machine (VM) requires different steps based on whether the VM is reponsive. Shutting down a responsive VM If you are connected to the guest , use a shutdown command or a GUI element appropriate to the guest operating system. Note In some environments, such as in Linux guests that use the GNOME Desktop, using the GUI power button for suspending or hibernating the guest might instead shut down the VM. Alternatively, use the virsh shutdown command on the host: If the VM is on a local host: If the VM is on a remote host, in this example 192.0.2.1 : Shutting down an unresponsive VM To force a VM to shut down, for example if it has become unresponsive, use the virsh destroy command on the host: Note The virsh destroy command does not actually delete or remove the VM configuration or disk images. It only terminates the running instance of the VM, similarly to pulling the power cord from a physical machine. In rare cases, virsh destroy may cause corruption of the VM's file system, so using this command is only recommended if all other shutdown methods have failed. Verification On the host, display the list of your VMs to see their status. 2.5.2. Shutting down and restarting virtual machines by using the web console Using the RHEL 8 web console, you can shut down or restart running virtual machines. You can also send a non-maskable interrupt to an unresponsive virtual machine. 2.5.2.1. Shutting down virtual machines in the web console If a virtual machine (VM) is in the running state, you can shut it down by using the RHEL 8 web console. Prerequisites You have installed the RHEL 8 web console. You have enabled the cockpit service. Your user account is allowed to log in to the web console. For instructions, see Installing and enabling the web console . The web console VM plug-in is installed on your system . Procedure In the Virtual Machines interface, find the row of the VM you want to shut down. On the right side of the row, click Shut Down . The VM shuts down. Troubleshooting If the VM does not shut down, click the Menu button ... to the Shut Down button and select Force Shut Down . To shut down an unresponsive VM, you can also send a non-maskable interrupt . Additional resources Starting virtual machines by using the web console Restarting virtual machines by using the web console 2.5.2.2. Restarting virtual machines by using the web console If a virtual machine (VM) is in the running state, you can restart it by using the RHEL 8 web console. Prerequisites You have installed the RHEL 8 web console. You have enabled the cockpit service. Your user account is allowed to log in to the web console. For instructions, see Installing and enabling the web console . The web console VM plug-in is installed on your system . Procedure In the Virtual Machines interface, find the row of the VM you want to restart. On the right side of the row, click the Menu button ... . A drop-down menu of actions appears. In the drop-down menu, click Reboot . The VM shuts down and restarts. Troubleshooting If the VM does not restart, click the Menu button ... to the Reboot button and select Force Reboot . To shut down an unresponsive VM, you can also send a non-maskable interrupt . Additional resources Starting virtual machines by using the web console Shutting down virtual machines in the web console 2.5.2.3. Sending non-maskable interrupts to VMs by using the web console Sending a non-maskable interrupt (NMI) may cause an unresponsive running virtual machine (VM) to respond or shut down. For example, you can send the Ctrl + Alt + Del NMI to a VM that is not responding to standard input. Prerequisites You have installed the RHEL 8 web console. You have enabled the cockpit service. Your user account is allowed to log in to the web console. For instructions, see Installing and enabling the web console . The web console VM plug-in is installed on your system . Procedure Log in to the RHEL 8 web console. For details, see Logging in to the web console . In the Virtual Machines interface, find the row of the VM to which you want to send an NMI. On the right side of the row, click the Menu button ... . A drop-down menu of actions appears. In the drop-down menu, click Send non-maskable interrupt . An NMI is sent to the VM. Additional resources Starting virtual machines by using the web console Restarting virtual machines by using the web console Shutting down virtual machines in the web console 2.6. Deleting virtual machines To delete virtual machines in RHEL 8, use the command line or the web console GUI . 2.6.1. Deleting virtual machines by using the command line To delete a virtual machine (VM), you can remove its XML configuration and associated storage files from the host by using the command line. Follow the procedure below: Prerequisites Back up important data from the VM. Shut down the VM. Make sure no other VMs use the same associated storage. Procedure Use the virsh undefine utility. For example, the following command removes the guest1 VM, its associated storage volumes, and non-volatile RAM, if any. Additional resources virsh undefine --help command virsh man page on your system 2.6.2. Deleting virtual machines by using the web console To delete a virtual machine (VM) and its associated storage files from the host to which the RHEL 8 web console is connected with, follow the procedure below: Prerequisites You have installed the RHEL 8 web console. You have enabled the cockpit service. Your user account is allowed to log in to the web console. For instructions, see Installing and enabling the web console . You have installed the RHEL 8 web console. You have enabled the cockpit service. Your user account is allowed to log in to the web console. For instructions, see Installing and enabling the web console . The web console VM plug-in is installed on your system . Back up important data from the VM. Make sure no other VM uses the same associated storage. Optional: Shut down the VM. Procedure Log in to the RHEL 8 web console. For details, see Logging in to the web console . In the Virtual Machines interface, click the Menu button ... of the VM that you want to delete. A drop down menu appears with controls for various VM operations. Click Delete . A confirmation dialog appears. Optional: To delete all or some of the storage files associated with the VM, select the checkboxes to the storage files you want to delete. Click Delete . The VM and any selected storage files are deleted. Additional resources Getting started with virtualization on IBM POWER Getting started with virtualization on IBM Z

Commands:
yum module install virt
yum install virt-install virt-viewer
systemctl start libvirtd
virt-host-validate [...] QEMU: Checking for device assignment IOMMU support : PASS QEMU: Checking if IOMMU is enabled by kernel : WARN (IOMMU appears to be disabled in kernel. Add intel_iommu=on to kernel cmdline arguments) LXC: Checking for Linux >= 2.6.26 : PASS [...] LXC: Checking for cgroup 'blkio' controller mount-point : PASS LXC: Checking if device /sys/fs/fuse/connections exists : FAIL (Load the 'fuse' module to enable /proc/ overrides)
QEMU: Checking for hardware virtualization: FAIL (Only emulated CPUs are available, performance will be significantly limited)
virt-install --graphics vnc --name demo-guest1 --memory 2048 --vcpus 2 --disk size=80 --os-variant win10 --cdrom /home/username/Downloads/Win10install.iso
virt-install --graphics vnc --name demo-guest2 --memory 4096 --vcpus 4 --disk none --livecd --os-variant rhel8.0 --cdrom /home/username/Downloads/rhel8.iso
virt-install --graphics vnc --name demo-guest3 --memory 2048 --vcpus 2 --os-variant rhel8.0 --import --disk /home/username/backup/disk.qcow2
virt-install --graphics vnc --name demo-guest4 --memory 2048 --vcpus 2 --disk size=160 --os-variant rhel8.0 --location http://example.com/OS-install --initrd-inject /home/username/ks.cfg --extra-args="inst.ks=file:/ks.cfg console=tty0 console=ttyS0,115200n8"
virt-install --name demo-guest5 --memory 16384 --vcpus 16 --disk size=280 --os-variant rhel8.0 --location RHEL8.iso --graphics none --extra-args='console=ttyS0'
virt-install --connect qemu+ssh://root@192.0.2.1/system --name demo-guest6 --memory 16384 --vcpus 16 --disk size=280 --os-variant rhel8.0 --location RHEL8.iso --graphics none --extra-args='console=ttyS0'
{PackageManagerCommand} info libvirt-daemon-config-network Installed Packages Name : libvirt-daemon-config-network [...]
virsh net-list --all Name State Autostart Persistent -------------------------------------------- default active yes yes
virsh net-autostart default Network default marked as autostarted virsh net-start default Network default started
error: failed to get network 'default' error: Network not found: no network with matching name 'default'
{PackageManagerCommand} reinstall libvirt-daemon-config-network
error: Failed to start network default error: internal error: Network is already in use by interface ens2
virsh start demo-guest1 Domain 'demo-guest1' started
virsh -c qemu+ssh://root@192.0.2.1/system start demo-guest1 root@192.0.2.1's password: Domain 'demo-guest1' started
virsh autostart demo-guest1 Domain ' demo-guest1 ' marked as autostarted
mkdir -p /etc/systemd/system/libvirtd.service.d/
touch /etc/systemd/system/libvirtd.service.d/10-network-online.conf
[Unit] After=network-online.target
virsh dominfo demo-guest1 Id: 2 Name: demo-guest1 UUID: e46bc81c-74e2-406e-bd7a-67042bae80d1 OS Type: hvm State: running CPU(s): 2 CPU time: 385.9s Max memory: 4194304 KiB Used memory: 4194304 KiB Persistent: yes Autostart: enable Managed save: no Security model: selinux Security DOI: 0 Security label: system_u:system_r:svirt_t:s0:c873,c919 (enforcing)
cat /etc/systemd/system/libvirtd.service.d/10-network-online.conf [Unit] After=network-online.target
virt-viewer guest-name
virt-viewer --direct --connect qemu+ssh://root@192.0.2.1/system guest-name root@192.0.2.1's password:
yum install libvirt-nss
passwd: compat shadow: compat group: compat hosts: files libvirt_guest dns
ssh root@192.0.2.1 root@192.0.2.1's password: Last login: Mon Sep 24 12:05:36 2021 root~#
ssh root@testguest1 root@testguest1's password: Last login: Wed Sep 12 12:05:36 2018 root~]#
virsh list --all Id Name State ---------------------------------------------------- 2 testguest1 running - testguest2 shut off
sudo grep GRUB_TERMINAL /etc/default/grub GRUB_TERMINAL=serial
virsh dumpxml vm-name | grep console <console type='pty' tty='/dev/pts/2'> </console>
cat /proc/cmdline BOOT_IMAGE=/vmlinuz-3.10.0-948.el7.x86_64 root=/dev/mapper/rhel-root ro console=tty0 console=ttyS0 ,9600n8 rd.lvm.lv=rhel/root rd.lvm.lv=rhel/swap rhgb
grubby --update-kernel=ALL --args="console=ttyS0"
grub2-editenv - unset kernelopts
systemctl status serial-getty@ttyS0.service ○ serial-getty@ttyS0.service - Serial Getty on ttyS0 Loaded: loaded (/usr/lib/systemd/system/serial-getty@.service; enabled; preset: enabled)
virsh console guest1 --safe Connected to domain 'guest1' Escape character is ^] Subscription-name Kernel 3.10.0-948.el7.x86_64 on an x86_64 localhost login:
virsh -c qemu+ssh://root@ 192.0.2.1/system list root@192.0.2.1's password: Id Name State --------------------------------- 1 remote-guest running
virsh -c remote-host list root@192.0.2.1's password: Id Name State --------------------------------- 1 remote-guest running
vi ~/.ssh/config Host example-host-alias User root Hostname 192.0.2.1
vi /etc/libvirt/libvirt.conf uri_aliases = [ " example-qemu-host-alias =qemu+ssh:// example-host-alias /system", ]
virsh -c example-qemu-host-alias list root@192.0.2.1's password: Id Name State ---------------------------------------- 1 example-remote-guest running
These can be used in cases when no URI is supplied by the application (@uri_default also prevents probing of the hypervisor driver). # uri_default = "example-qemu-host-alias"
virsh list root@192.0.2.1's password: Id Name State --------------------------------- 1 example-remote-guest running
virsh dumpxml <vm-name> | grep graphics <graphics type='vnc' ports='-1' autoport= yes listen= 127.0.0.1 > </graphics>
virsh edit <vm-name>
<graphics type='vnc' ports='-1' autoport= yes listen= 127.0.0.1 passwd=' <password> '>
<graphics type='vnc' ports='-1' autoport= yes listen= 127.0.0.1 passwd=' <password> ' passwdValidTo='2025-02-01T15:30:00' >
virsh start <vm-name>
virt-viewer <vm-name>
virsh shutdown demo-guest1 Domain 'demo-guest1' is being shutdown
virsh -c qemu+ssh://root@192.0.2.1/system shutdown demo-guest1 root@192.0.2.1's password: Domain 'demo-guest1' is being shutdown
virsh destroy demo-guest1 Domain 'demo-guest1' destroyed
virsh list --all Id Name State ------------------------------------------ 1 demo-guest1 shut off
virsh undefine guest1 --remove-all-storage --nvram Domain 'guest1' has been undefined Volume 'vda'(/home/images/guest1.qcow2) removed.