Citrix Provisioning

Streaming Linux target devices

This article provides information about streaming Linux target devices. Using the Linux streaming feature with Citrix Provisioning, you can provision Linux virtual desktops in the Citrix Virtual Apps and Desktops environment.

You can use UEFI and secure boot with Citrix Provisioning version 2106 and later.

Using the Linux streaming feature with Citrix Provisioning, you can provision Linux virtual desktops in the Citrix Virtual Apps and Desktops environment. For more information about the Linux streaming feature, see Use Citrix Provisioning to create Linux VMs.

Important:

We recommend that you use the current release installation package, available in the Citrix Provisioning executable, Citrix_Provisioning_2109.iso. Use the package based on your Linux distribution. Citrix Provisioning Server 2109 or later is required to use Linux streaming agent 2109 and later.

Consider the following when provisioning Linux target devices:

  • When you use Citrix Provisioning to stream Linux target devices, create a separate boot partition on the single shared-disk image so that the provisioned devices can boot as expected.
  • Sometimes, the client drive cannot be mapped to a provisioned Linux VM session. To resolve this issue, halt the CDM service using service ctxcdm stop, before installing the Citrix Provisioning target device, then run the pvs-imager command to convert it.
  • Linux streaming only supports Winbind as the tool for joining a Windows domain. Winbind provided by Samba 4.5 and newer is supported, including older releases.
  • When you enable RAM cache for the Linux device, set the cache size to 8 MB (the minimum value). Linux uses as much RAM as necessary, including all available memory, for the write cache. The amount specified in the console is the amount reserved up front. Citrix recommends that you reserve as little as possible, which effectively allows Linux to manage memory usage.
  • The target device name in the Citrix Provisioning imager UI typically defaults to im\_localhost. This value must be changed when you create more than one vDisk. Using the same target device name causes the imager command to fail.
  • Installation (and subsequent updates) must be done in super user mode. There are two ways to install as a super user:
    • Enter user mode in a terminal using the su command.
    • Enter sudo before the command. For example, sudo yum install tdb-tools; enter sudo for every command.
  • The Linux client’s system clock must be synchronized by using the active directory controller.
  • VMM is not supported.
  • The write cache drive must have the label PVS_Cache for it to be used as a write cache. The entire partition is used.
  • English localizations are displayed on non-English installations.
  • SE Linux is not supported.
  • Targets running on XenServer must run in HVM mode.
  • After booting a Linux target device, a warning message might display indicating a SE Linux Alert Browser.
  • The following Linux distributions are supported:
    • Ubuntu 16.04
    • Ubuntu 18.04
    • Ubuntu 20.04
    • RHEL 8.4
    • RHEL 8.3
    • RHEL 7.9
    • SUSE 12.5
  • Two streamed Ubuntu 18.04 or Ubuntu 20.04 VMs hosted on ESXi get the same IP address through DHCP. To resolve this issue, configure the VM to use the MAC address as a unique ID to retrieve an IP address through DHCP.
  • On Ubuntu 18.04, when installing the installation package an error may appear: dracut-install: Failed to find module ‘crc32c’. This is a known issue of Ubuntu 18.04. To resolve it, comment add_drivers+=”crc32c” in /etc/dracut.conf.d/10-debian.conf and reinstall the package.
  • Create a vDisk using UEFI boot from a master VM using UEFI boot.
  • To use secure boot for a streamed VM, the master VM which creates the vDisk does not need to enable secure boot.

Installation options

To install the Linux Streaming component, you must be logged in while an administrator. If installing, consider that the following commands must be issued in a root shell, or by using sudo privileges.

Install a self-signed certificate

A self-signed certificate must be created for streaming Citrix Provisioning Linux target devices. The Soap server uses an SSL connection requiring you to configure an X.509 certificate on the Soap server.

The certificate’s CA must also be present on the Provisioning Server and the Linux target device. For information on creating a self-signed certificate, see Creating self-signed certificates for Linux streaming.

Use the following commands to install a self-signed certificate:

  • Ubuntu:
sudo cp certificate.crt /usr/local/share/ca-certificates/
sudo update-ca-certificates
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  • RHEL:
sudo yum install ca-certificates
sudo update-ca-trust force-enable
sudo cp certificate.crt /etc/pki/ca-trust/source/anchors/
sudo update-ca-trust extract
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Use trust list to see if the certificate is installed correctly.

Install the linux streaming package

For Ubuntu 16.04 distributions:

apt-get -y install dracut dracut-network
dpkg -r nbd-client
dpkg -i pvs_<version>_ubuntu16.04_amd64.deb
apt-get -fy install
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For Ubuntu 18.04 distributions:

apt-get -y install dracut dracut-network
apt-get -y install pvs_<version>_ubuntu18.04_amd64.deb
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For Ubuntu 20.04 distributions:

apt-get -y install pvs_<version>_ubuntu20.04_amd64.deb`
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For RHEL 8.4 and RHEL 8.3 distributions:

yum --nogpgcheck localinstall pvs_<version>_rhel8.3_x86_64.rpm
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For RHEL 7.9 distributions:

yum --nogpgcheck localinstall pvs_<version>_rhel7.9_x86_64.rpm
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For SUSE 12.5 distributions:

zypper install pvs_<version>_suse12.5_x86_64.rpm
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Using the GUI to create a Linux golden image

To invoke the GUI to install this feature:

  1. Log in while an administrator.
  2. Run the following:

    pvs-imager

Tip:

When the pvs-imager command fails due to a host name issue, verify that your network configuration is correct. Do not set the system’s host name to localhost. On RHEL 8.3, log in with the X11 display server instead of Wayland to use the GUI. PyQt5 or python3-pyqt5 is required to use the GUI.

After running the command, the UI page displays:

Provisioning imaging tool

Using the command line interface to install the Linux streaming feature

To invoke the command line to install this feature:

  1. Log in while an administrator.
  2. Run the following command:

    pvs-imager -C

The command-line installation includes two options:

  • \-C allows you to create a vDisk
  • \-U allows you to update an existing vDisk

The following information illustrates non-GUI related installation options for the Linux Streaming feature:

Usage: ./pvs-imager [-hCU] [-a|--address=<IPaddr>] [-u|--username=<username>] [-p|--password=<password>] [-P|--port=<port>] [-d|--domain=<domain] [-S|--store=<store>] [-v|--vdisk=<vdisk name>] [-s|--size=<vdisk size] [-D|--device=<sourceDevice>] [-c|--collection=<collection>] [-n|--name=<name>]
 Non-GUI Modes:
  -C      -  Create a new vDisk
    ---OR----
  -U      -  Update an existing vDisk

 General Options:
  -a <server IP> -  Address or hostname of PVS server
  -u <username>  -  Username for API login
  -p <password>  -  Password for API login
  -d <domain>   -  AD domain for API login
  -P <port>    -  Base port for API login (default: 54321)
  -S <store>   -  Store containing vDisk
  -c <collection> -  Collection to store imaging device in
  -n <name>    -  Device name for imaging device
  -v <name>    -  vDisk name
  -s <size>    -  vDisk size (Create Mode only, default: sourceDevice size)
  -D <sourceDev> -  devnode to clone
  -V       -  increment debug verbosity (up to 5 times)
  -g <grubMode>  -  Supported Grub settings ('debug')

Supported file systems for imaging are ext4, xfs, or btrfs.

Tip:

Debugging logs for pvs-imager, created using -VVVVV switch, are created in the folder that executed the pvs-imager tool. The name of the log file is pvs-imager.log.

About disk caching

For hard disk caching or hard disk overflow caching without the Citrix Virtual Apps and Desktops Setup Wizard, format the target device disk using a formatted partition. Include the label PVS_Cache. This object can be created with the mkfs –L PVS_Cache command on the target device. Any case-sensitive file system can be used for the cache, but XFS is recommended.

Tip:

An administrator can create any cache disk selection logic for their environment by writing a bash script that runs at launch time. The script would look for a cache device candidate by whatever mechanism is best suited to the environment, running mkfs on it, and rebooting.

When configuring disk caching:

  • Citrix recommends using the Citrix Virtual Apps and Desktops Setup Wizard to create the Linux target device.
  • Manually creating the label requires adherence to case sensitivity to avoid configuration conflicts.
  • Alternately, consider using the manual method for creating the write cache.

Manually creating the write cache for a target device

By default, the Citrix Virtual Apps and Desktops Setup Wizard ignores drives that are attached to the current template. The wizard creates a write cache based on parameters you provide. Sometimes, the write cache drive encounters problems during automatic creation using the wizard, or, when the target device continuously falls back to server side cache as a result of a problem with the created drive. To resolve these issues, manually create the object using the mkfs –L PVS_Cache command on the target device.

The Citrix Virtual Apps and Desktops Setup Wizard recognizes manually created write cache changes for the target device by default when you use the UseTemplatecache parameter. On the provisioning server running the Citrix Virtual Apps and Desktops Setup Wizard, or where the remote provisioning console points, change the registry setting:

  1. Create the following registry key on the provisioning console machine to disable the template cache:

HKEY_LOCAL_MACHINE\SOFTWARE\Citrix\ProvisioningServices

Name: UseTemplateCache

Type: DWORD

Value: 0

  1. Run the Citrix Virtual Apps and Desktops Setup Wizard. On the Virtual machines page change the local write cache disk size to 0 GB (default is 6 GB).
Streaming Linux target devices