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High Availability for TFTP with
Provisioning Services
Implementation Guide
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Contents
Overview ............................................................................................................................................................. 3
Options ................................................................................................................................................................ 4
DNS Round Robin Entry.............................................................................................................................................. 5
DHCP with Multiple Entries ........................................................................................................................................ 5
Provisioning Services PXE Broadcast ......................................................................................................................... 5
Provisioning Services Boot Device Manager ............................................................................................................. 6
NetScaler Use Source IP................................................................................................................................................ 6
NetScaler Direct Server Return .................................................................................................................................... 7
NetScaler Global Server Load Balancing .................................................................................................................... 7
Summary ........................................................................................................................................................................... 8
Implementation Guide ...................................................................................................................................... 9
Prerequisites ................................................................................................................................................................... 10
NetScaler General Configuration ............................................................................................................................... 14
NetScaler – Use Source IP .......................................................................................................................................... 17
NetScaler – Direct Server Return ............................................................................................................................... 22
NetScaler – Global Server Load Balancing .............................................................................................................. 28
Appendix A – Environment Details ............................................................................................................. 35
Appendix B – Reference Documentation .................................................................................................... 35
Revision History ............................................................................................................................................... 37
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Overview
Citrix Provisioning Services is a software streaming technology that allows servers and desktops to
be provisioned and re-provisioned in real time from a single shared-disk image1. The service is
commonly integrated with Citrix virtualization solutions to optimize Operating System delivery and
management.
Often these solutions are critical to the operation of organizations and require high availability.
Providing high availability for Provisioning Services requires designing each component of the
service without a single point of failure across the network. The „bootstrap file‟, named
ardbp32.bin, is a key component that must be delivered to Provisioning Services target devices in
order for them to communicate with Provisioning Services over the network.
The bootstrap file is typically delivered via Trivial File Transfer Protocol (TFTP) services hosted on
Provisioning Servers. This document focuses specifically on comparing high availability options for
delivery of the bootstrap file to target devices via TFTP. The advantages and disadvantages of each
option are outlined as well as the steps to implement the load balancing options with NetScaler.
The document scope does not include details of the implementation or operation of other aspects of
Provisioning Services.
1 http://support.citrix.com/proddocs/topic/technologies/pvs-provisioning.html
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Options
The options under consideration share common components including:
Dynamic Host Configuration Protocol (DHCP)2: Provides hosts with networking
information they need to communicate on the network. It provides a host with an IP
address, gateway, and DNS server(s) by default. Two additional “options” carry additional
information that are used by Provisioning Services target devices to obtain their bootstrap
file.
o Option 66: Defines the Boot Server Host Name, which corresponds to the TFTP
Server DNS name or IP address
o Option 67: Defines the Bootfile Name, which is typically ardbp32.bin
Pre-boot Execution Environment (PXE)3: Is a program included in computer firmware
that enables it to boot over the network. It relies on DHCP to obtain information necessary
to boot. When a computer first attempts a PXE boot it broadcasts a DHCP request over its
Network Interface Card (NIC)/(s).
Trivial File Transfer Protocol (TFTP)4: Provides PXE clients with their bootstrap file.
Clients are typically notified of the TFTP Server/(s) and the bootstrap file name through
DHCP options. The lab environment used to implement the options has a TFTP service
running on each Provisioning Services server, so they will be referenced as Provisioning
Services/TFTP Servers.
Domain Name System (DNS)5: Allows common names to be mapped to and from IP
addresses. By providing dynamic allocation of its directory information Provisioning
Services target devices may be presented with different Provisioning Services/TFTP Server
IP addresses providing a rudimentary level of redundancy.
The core concept with regards to providing high availability to TFTP is being able to deliver the
bootstrap file to the Provisioning Services target device. Once the bootstrap is delivered, the target
device can communicate to multiple Provisioning Services servers. There are many different ways
for providing high availability for the TFTP services, but the following seven are the most common:
1. DNS Round Robin Entry
2. DHCP with Multiple Entries
3. Provisioning Services PXE Broadcast
2 http://en.wikipedia.org/wiki/Dynamic_Host_Configuration_Protocol
3 http://en.wikipedia.org/wiki/Preboot_Execution_Environment
4 http://en.wikipedia.org/wiki/Trivial_File_Transfer_Protocol
5 http://en.wikipedia.org/wiki/Domain_Name_System
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4. Provisioning Services Boot Device Manager
5. NetScaler Use Source IP (USIP)
6. NetScaler Direct Server Return (DSR)
7. NetScaler Global Server Load Balancing (GSLB)
DNS Round Robin Entry
With this option, a TFTP server DNS name is carried in DHCP option 66. The DNS server
then would have two or more A records defined for the domain name and cycle through the list
of records in round robin fashion in response to DNS queries. This provides Provisioning
Services target devices with redundancy in obtaining their Bootfile.
Advantages of this option:
o It is easy to implement requiring limited changes to DHCP and DNS servers.
Disadvantages of this option:
o It may not monitor the state of target TFTP servers, depending on the DNS
server; therefore it could potentially send requests to servers that are not
functioning.
DHCP with Multiple Entries
This option requires a DHCP implementation that allows multiple Boot Server Host Name
entries to be carried within the option 66 field.
Advantages of this option:
o It is easy to implement requiring limited changes to DHCP servers only.
Disadvantages of this option:
o It does not monitor the state of target TFTP servers; therefore it could send
requests to servers that are not functioning.
Provisioning Services PXE Broadcast
With this option a PXE boot server is hosted by Provisioning Services servers. After
Provisioning Services target devices obtain their IP address and gateway through DHCP, they
start broadcasting a TFTP boot request. Provisioning Services servers hosting PXE boot
services on the same network as the target devices will receive boot requests and respond directly.
For those on different subnets, routers may be configured with a IP/UDP helper address entry,
which allows the router to forward the initial Provisioning Services Client PXE boot broadcasts.
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Without the helper address, the requests would otherwise be contained within the subnet and
unable to reach the PXE service.
Advantages of this option:
o It is easy to implement, requiring limited changes to routers only.
o IP/UDP helper address entries are typically already configured within networks
to deliver client DHCP requests to DHCP server farms.
Disadvantages of this option:
o It increases traffic on the network and can present risks to its capacity in the
event of a malfunctioning PXE client, or virus that sends excessive broadcasts.
Provisioning Services Boot Device Manager
This Provisioning Services option is different than the other options in that it does not rely on
the client PXE booting itself from a TFTP Server. Rather, the Boot Device Manager creates a
Bootfile that the target device can obtain via an ISO image mounted to the virtual machine as a
DVD drive. For this to be a high-availability option for delivery of the Bootfile, the network
share containing the ISO file must be redundant.
Advantages of this option:
o It has limited reliance on the network infrastructure.
Disadvantages of this option:
o It requires changes to the target device boot process (boot via DVD instead of
network).
o Updating the ISO file is a manual process, which is why the addresses used within
the file should be a fully qualified domain name, whose IP address can be updated
in DNS later.
NetScaler Use Source IP
This option relies on the NetScaler to load balance the target device‟s initial TFTP boot request
to a TFTP Server. The target devices must obtain the IP address of the NetScaler Virtual Server
IP (VIP) through DHCP option 66. Once the NetScaler receives the boot request, it is directed
to one of the TFTP servers from the pool by changing the destination IP address. The source IP
address is not changed, therefore the TFTP server replies to the target device directly.
Advantages of this option:
o Provides traffic surge protection for servers.
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Disadvantages of this option:
o None
NetScaler Direct Server Return
This option is similar to the NetScaler – Use Source IP option, but it makes its load balancing
decision based on the frame MAC Address and does not change the target destination IP
address. Therefore the target TFTP Server must have a loopback IP address corresponding to
the NetScaler VIP.
Advantages of this option:
o Provides robust scalability and availability as with the NetScaler-Use Source IP
option.
Disadvantages of this option:
o Requires configuring a loopback address on the TFTP Servers
NetScaler Global Server Load Balancing
This option takes advantage of the NetScaler ability to integrate with DNS to control responses
to queries while monitoring the availability of TFTP servers. Upon receiving a DNS query for
the TFTP boot server domain name, the NetScaler dynamically responds with the best option,
according to the selection algorithm configured.
Advantages of this option:
o Provides availability monitoring of Provisioning Services/TFTP Servers
Disadvantages of this option:
o Requires a NetScaler Platinum license or individual GSLB license
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Summary
Based on all of the options, the following provides a quick summary for how difficult they are to
implement, how scalable they are and how fault tolerant they are (ability to identify issues and
reroute requests appropriately).
Option Difficulty Scalability Fault Tolerance
DNS Round Robin Entry Low Medium Low
DHCP with Multiple Entries Low Low Low
Provisioning Services PXE Broadcast Low Medium Medium
Provisioning Services Boot Manager Medium Medium High
NetScaler Use Source IP Low High High
NetScaler Direct Server Return Medium High High
NetScaler Global Server Load Balancing High High High
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Implementation Guide
Of the previously mentioned high availability options for TFTP, the three NetScaler options require
additional help in the setup/configuration. This section of the document focuses on the
implementation of the NetScaler options.
For the NetScaler options, the following figure shows the conceptual network topology:
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Prerequisites
Below is a complete list of components required to implement the NetScaler based options
within a lab environment.
Prerequisites
The following components must be installed to complete the implementation scenarios contained in this section
Install a XenServer capable of hosting all required Virtual Machines (VMs)
Install 2 Provisioning Services VMs including:
o The TFTP Server component configured
o A license server & license
o A Provisioning Services Bootstrap with pertinent configuration
Install a Domain Controller(DC) VM including:
o A DHCP service with pertinent options set
o A DNS service with pertinent A records configured
Install a Vyatta Router VM with pertinent settings configured
Install a NetScaler VM with pertinent settings configured & license applied
Install 2 Provisioning Services Clients
o One on the XenServer internal network Provisioning Services – TFTP
o Another on the XenServer internal network Provisioning Services – TFTP2
Screenshot Description
Install a XenServer
XenServer version 5.6_SP2 running on an HP Proliant 380 with 16MB RAM and an internal HD was used for this setup
The XenServer hosts 6 VMs described in the following blocks and 3 Networks described below
Provisioning Services – TFTP is an internal network that corresponds to subnet 192.168.0.0/24
Provisioning Services – TFTP2 is an internal network that corresponds to subnet 10.95.95.0/24
Network 1 corresponds to an external network used for management access only that corresponds to subnet 172.17.2.0/24
See Appendix B - Reference Documentation for more information regarding installation
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Prerequisites
Install a NetScaler VM
NetScaler version 9.3_51_nc
Add an interface to network ProvisioningServices - TFTP
NOTE: The NetScaler should be configured in a High Availability pair
See Appendix B - Reference Documentation for more information regarding installation
Install a Vyatta Router VM
Vyatta Version 2.6.35-1
Add an interface to network ProvisioningServices - TFTP
Add an interface to network ProvisioningServices – TFTP2
See Appendix B - Reference Documentation for more information regarding installation
Install a Domain Controller with DHCP and DNS Roles
Add an interface to Provisioning Services– TFTP
Add an interface to Provisioning Services– TFTP2
Add an interface to Network 1
See Appendix B - Reference Documentation for more information regarding installation
Configure Domain Controller
Create Domain “pvslab.com”
See Appendix B - Reference Documentation for more information regarding installation
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Prerequisites
Configure DHCP Server
Open the Windows Server Manager
Select the DHCP Server Role
Configure Scope 192.168.0.0 corresponding to network Provisioning Services – TFTP1 with Address Pool 192.168.0.50-192.168.0.59
Configure Scope 10.95.95.0 corresponding to network Provisioning Services – TFTP2 with Address Pool 10.95.95.50-10.95.95.59
See Appendix B - Reference Documentation for more information regarding installation
Install Provisioning Services Client VMs
Provisioning Services Client1 is a XenServer VM with an interface on an internal network Provisioning Services – TFTP
Provisioning Services Client2 is a XenServer VM with an interface on an internal network Provisioning Services – TFTP2
Set Provisioning Services client Boot Option:
Select the Provisioning Services Client 1 VM
o Select General Tab
o Select Properties
o Select Boot Options
o Specify: Network and ensure other options are unchecked
Repeat for the Provisioning Services Client 2 VM
See Appendix B - Reference Documentation for more information regarding installation
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Prerequisites
Install Provisioning Services/TFTP Server VMs
For both Provisioning Services/TFTP Server 1 & 2:
Add an interface to Provisioning Services– TFTP
Add an interface to Network 1
Install Provisioning Services Version 5.6.2including:
o TFTP Server ProvisioningServices Bootstrap withpertinent configuration
See Appendix B - Reference Documentation for more information regarding installation
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NetScaler General Configuration
Base Configuration
Screenshot Description
Configure the NetScaler with a NetScaler IP (NSIP) address and a default gateway.
2
Download your license and the latest NetScaler firmware from www.mycitrix.com.
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Base Configuration
Screenshot Description
Connect to the NetScaler
Enter the NetScaler‟s IP Address (NSIP) in the web browser: http://192.168.0.95
Log into the Configuration system with theID and Password
NOTE: The default credentials are:
Username = nsroot
Password = nsroot
Apply license file
Under:
>System>License>Manage Licenses>Add
Upload your license file to the NetScalerusing the License utility
3
Upgrade the NetScaler
Under:
>NetScaler>Upgrade Wizard
Follow the wizard prompts. Enter „Yes‟when prompted whether to reboot.
Re-connect to the NetScaler after it hasrebooted
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Base Configuration
Screenshot Description
Enable Load Balancing
Under:
>System>Settings>Configure Basic Features
Select:
Enable Load Balancing
Add Provisioning Services/TFTP Servers
Under:
>Load Balancing>Servers
In order to load balance TFTP services, the servers hosting the service must first be defined by doing the following:
Select Add from the bottom menu bar
In the Create Server window, enter in thefollowing information for the firstProvisioning Services/TFTP Server:
o Server Name: pvs-server1
o IP Address: 192.168.0.98
o Select Create
For the second ProvisioningServices/TFTP Server, enter in thefollowing:
o Server Name: pvs-server2
o IP Address: 192.168.0.99
o Select Create
Select Close
Each Server entry should appear “green”.If not check reachability from theNetScaler SNIP to the servers
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NetScaler – Use Source IP
The network topology pertaining to implementation of this option is shown in the following
figure:
With this option, each of the Provisioning Services Client VMs are restarted and follow the
respective paths, outlined above, sequentially to obtain their bootfile.
Provisioning Services Client 1
o Broadcasts a DHCP request, which is replied to by the DHCP Server carrying its
IP address, Gateway, Boot Server Host Name, and Bootfile Name.
o Sends a TFTP boot request to the NetScaler VIP obtained from the Boot Server
Host Name field in DHCP.
o The NetScaler makes a load balancing decision and subsequently in this case
changes the destination IP address to that of Provisioning Services/TFTP Server
1 where it directs the boot request.
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o Provisioning Services/TFTP Server 1 receives the boot request with the source
IP address of Provisioning Services Client 1 and sends it the initial segment of its
bootfile
Provisioning Services Client 2
o Broadcasts a DHCP request which is replied to by the DHCP Server carrying its
IP address, Gateway, Boot Server Host Name, and Bootfile Name.
o Sends a TFTP boot request to the NetScaler VIP via its gateway, the Vyatta
router.
o The NetScaler makes a load balancing decision and subsequently in this case
changes the destination IP address to that of Provisioning Services/TFTP Server
2 where it directs the boot request.
o Provisioning Services/TFTP Server 2 receives the boot request with the source
IP address of Provisioning Services Client 2 and sends it the initial segment of its
bootfile.
Configuration
Screenshot Description
Configure a Subnet IP (SNIP)
Under:
>Network>IPs>
Select Add from the bottom menu bar
In the Configure IP window enter the following:
o IP Address: 192.168.0.94
o Select: OK
This will be used as the source IP address for monitoring the Provisioning Services/TFTP Servers.
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Configuration
Screenshot Description
Add Provisioning Services Service Group
Under:
>Load Balancing>Service Groups
Select Add from the bottom menu bar
In the Create Service Group window enter the following:
o Service Group Name: Provisioning Services Service Group
o Protocol: ANY
o Select: pvs-server1 (192.168.0.99)
Select the Members tab:
o Select Server Based
o Highlight pvs-server1
o Port: *
o Select Add
o Highlight pvs-server2
o Port: *
o Select Add
Select the Advanced tab:
o Select:: Use Source IP
o Select Create
o Select Close
NOTE: The service group monitor was left as ping-default
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Configuration
Screenshot Description
Add Provisioning Services Virtual Server
Under:
>Load Balancing>Services
Select Add from the bottom menu bar
In the Create Virtual Server window, enter the following information:
o Name: tftp-any
o IP Address: 192.168.0.90
o Protocol: ANY
o Port: *
Select the Service Groups tab:
o Select: Provisioning Services Service Group
Select the Method & Persistence tab:
o Under Persistence Select: SOURCEIP
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Configuration
Screenshot Description
Configure DHCP Options
Open the Windows Server Manager
Select the DHCP Server Role
Configure Scope 192.168.0.0corresponding to network ProvisioningServices – TFTP2 with Scope Options:
o 066 Boot Server Host Name =192.168.0.90
o 067 Bootfile Name =ARDBP32.bin
Configure Scope 10.95.95.0 correspondingto network Provisioning Services – TFTP2with Scope Options:
o 066 Boot Server Host Name =192.168.0.90
o 067 Bootfile Name =ARDBP32.bin
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NetScaler – Direct Server Return
The network topology pertaining to implementation of this option is shown in the following
figure:
With this option each of the Provisioning Services Client VMs are restarted and follow the
respective paths, outlined above, sequentially to obtain their bootfile.
Provisioning Services Client 1
o Broadcasts a DHCP request which is replied to by the DHCP Server carrying its
IP address, Gateway, Boot Server Host Name, and Bootfile Name.
o Sends a TFTP boot request to the NetScaler VIP, obtained from the Boot Server
Host Name field in DHCP.
o The NetScaler makes a load balancing decision and directs the boot request to
Provisioning Services/TFTP Server 1. However in this case it does not change
the IP destination to Provisioning Services/TFTP Server 1, rather only the
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destination MAC address is modified. The frame arrives at Provisioning
Services/TFTP Server 1 with the same destination IP address as the NetScaler
VIP.
o Provisioning Services/TFTP Server 1 receives the boot request on its external
interface and forwards it to its loopback adapter with the same IP address as the
NetScaler VIP. It then sends to the source IP address, which is Provisioning
Services Client 1, the initial segment of its bootfile.
Provisioning Services Client 2
o Broadcasts a DHCP request which is replied to by the DHCP Server carrying its
IP address, Gateway, Boot Server Host Name, and Bootfile Name.
o Sends a TFTP boot request to the NetScaler VIP via its gateway, the Vyatta
router.
o The NetScaler makes a load balancing decision and directs the boot request to
Provisioning Services/TFTP Server 2. However in this case it does not change
the IP destination to Provisioning Services/TFTP Server 2, rather only the
destination mac address is modified. The frame arrives at Provisioning
Services/TFTP Server 2 with the same destination IP address as the NetScaler
VIP.
o Provisioning Services/TFTP Server 2 receives the boot request on its external
interface and forwards it to its loopback adapter with the same IP address as the
NetScaler VIP. It then sends to the source IP address, which is Provisioning
Services Client 2, the initial segment of its bootfile.
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Configuration of the DSR method is similar to the configuration for USIP, yet requires the
following changes to the NetScaler configuration:
Base Configuration
Screenshot Description
MAC Based Redirection Mode
Under:
>System>Load Balancing>Virtual Servers>
Highlight the „tftp-any‟ Virtual Server
Select: Open
Select: Advanced TAB
Select: MAC Based next to Redirection Mode
Select: Ok
Configuration of the DSR method also requires configuring a loopback on each Provisioning
Services/TFTP Server with an IP address which corresponds to the NetScaler VIP and setting
the TFTP service to listen on that loopback. Instructions are included for MS Windows Servers
only:
Base Configuration
Screenshot Description
Add MS Loopback adaptor to TFTP servers
For both Provisioning Services/TFTP Server 1 & 2:
From the Windows Start button:
o Right-click: Computer
o Select: Properties
o Select: Device Manager
o Right-click: <Computer Name>
o Select: Add Legacy Hardware
o Click: Next
o Select: Install the hardware I manually select from a list
o Click: Next
o Select: Network Adapters
o Click: Next
o Select: Microsoft
o Select: Microsoft Loopback Adapter
o Click: Next twice
o Click: Finish
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Base Configuration
Screenshot Description
Add VIP IP address to MS Loopback adaptor
For both Provisioning Services/TFTP Server 1 & 2:
From the Windows Start button:
o Select: Control Panel
o Select: Network and Internet
o Select: Network and SharingCenter
o Select: Local Area Connection 3
(The loopback being the lastadded will be the highestnumber)
o Select: Properties
o Select: Internet Protocol Version4
o Select: Properties
o Select: Use the following IPaddress
o Enter:
IP Address:192.168.0.90
Subnetmask:255.255.255.0
o Click: Ok & Close all otherwindows
NOTE: It is not necessary to specify a default gateway. This should already be specified on the primary interface as the Vyatta router.
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Base Configuration
Screenshot Description
Configure adapters to send and receive for loopback
This step is necessary in order to allow the server interfaces to send and receive traffic destine for the IP addresses of both the loopback and external interfaces
For both Provisioning Services/TFTP Server 1 & 2:
From the Windows Command prompt enter:
o netsh
o interface
o ipv4
o set interface "Local AreaConnection"weakhostreceive=enabled
o set interface "Local AreaConnection 3"weakhostreceive=enabled
o set interface "Local AreaConnection 3"weakhostsend=enabled
For more information see this article on Microsoft TechNet:
http://technet.microsoft.com/en-us/magazine/2007.09.cableguy.aspx
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Base Configuration
Screenshot Description
Bind TFTP Service to Loopback
This step is necessary in order to allow the Provisioning Services/TFTP Servers to receive TFTP requests on the loopback interface.
For both Provisioning Services/TFTP Server 1 & 2:
Open Windows Explorer:
o Browse to C:\Program Files\Citrix\Provisioning Services
o Double click tftpcpl.cpl
o Select the TFTP Network TAB
o Select the loopback 192.168.0.90
o Click OK
o Click Yes to restart the TFTP service
To verify open a DOS prompt and enter:
o Netstat –na | findstr 192.168.0.90:69
o The output should reflect the loopback listening on UDP port 69
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NetScaler – Global Server Load Balancing
The network topology pertaining to implementation of this option is shown in the following
figure:
With this option each of the Provisioning Services Client VMs are restarted and follow the
respective paths, outlined above, sequentially to obtain their bootfile.
Provisioning Services Client 1
o Broadcasts a DHCP request, which is replied to by the DHCP Server carrying its
IP address, Gateway, Boot Server Host Name, and Bootfile Name.
o Attempts to resolve the Boot Server Host Name „tftp‟ from the DNS Server.
o The DNS Server is configured with an alias for „tftp‟ that references the NetScaler
Authoritative DNS (ADNS) listener. A DNS name query is forwarded to
NetScaler1, from the DNS server, on behalf of Provisioning Services Client 1.
Once the NetScaler1 ADNS process receives the request it queries the GSLB
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process dynamically and based on the least connected algorithm returns the
Provisioning Services/TFTP Server 1 in the DNS reply.
o The DNS Server sends this DNS reply to Provisioning Services Client 1
o Sends a TFTP boot request to the Provisioning Services/TFTP Server 1 and it
initiates TFTP transfer of the bootfile to the Provisioning Services Client 1.
Provisioning Services Client 2
o Broadcasts a DHCP request, which is replied to by the DHCP Server carrying its
IP address, Gateway, Boot Server Host Name, and Bootfile Name.
o Attempts to resolve the Boot Server Host Name „tftp‟ from the DNS Server.
o The DNS Server is configured with an alias for „tftp‟ that references the NetScaler
Authoritative DNS (ADNS) listener. A DNS name query is forwarded to
NetScaler2, from the DNS server, on behalf of Provisioning Services Client 2.
Once the NetScaler2 ADNS process receives the request it queries the GSLB
process dynamically and based on the least connected algorithm returns the
Provisioning Services/TFTP Server 2 in the DNS reply.
o The DNS Server sends this DNS reply to Provisioning Services Client 2
o Sends a TFTP boot request to the Provisioning Services/TFTP Server 2 and it
initiates TFTP transfer of the bootfile to the Provisioning Services Client 2.
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The NetScaler - GSLB method is configured as follows:
Configuration
Screenshot Description
Enable GSLB Service
Under:
>System>Settings>Configure Advanced Features
Configure the ADNS Service
Under:
>Load Balancing> Services>
Select Add from the bottom menu bar
In the Configure IP window enter the following:
o Service Name: ADNS
o Protocol: ADNS
o Server: 192.168.0.94
o Port: 53
Select Create
Select Close
Add GSLB Site
Under:
>GSLB>Sites
Site1 – “Provisioning Services – TFTP”
o Select Add from the bottom menu bar
o In the Create GSLB site window enter the following:
o Name: Provisioning Services - TFTP
o Site Type: LOCAL
o Site IP Address: 192.168.0.94
o Select Create
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Configuration
Screenshot Description
Add GSLB Services
Under:
>GSLB>Services
Provisioning Services – TFTP – SERVER1
Select Add from the bottom menu bar
In the Create GSLB Service window enterthe following:
o Service Name: Provisioning Services –TFTP – SERVER1
o Server Name: pvs-server1
o Service Type: UDP
o Port: 69
Select Create
Provisioning Services – TFTP – SERVER2
Again In the Create GSLB Service windowenter the following:
o Service Name: Provisioning Services –TFTP – SERVER2
o Server Name: pvs-server2
o Service Type: UDP
o Port: 69
Select Create
Select Close
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Configuration
Screenshot Description
Add GSLB Virtual Server
Under:
>GSLB>Virtual Servers
Select Add from the bottom menu bar
In the Create GSLB Virtual Server window
Under the Services Tab:
o Select: Provisioning Services – TFTP – SERVER1
o Select: Provisioning Services – TFTP – SERVER2
NOTE: The “Effective State” will show DOWN the state of the services is not being communicated via MEP since a remote site is not being used.
Under the Domain Tab:
o Select Add
o Enter Domain Name: tftp.gslb.pvslab.com
Select Create
Select Close
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Configuration
Screenshot Description
Update DHCP Options
Open the Windows Server Manager
Select the DHCP Server Role
Configure Scope 192.168.0.0corresponding to network ProvisioningServices – TFTP2 with Scope Options:
o 066 Boot Server Host Name =tftp.pvslab.com
o 067 Bootfile Name =ARDBP32.bin
Configure Scope 10.95.95.0 correspondingto network Provisioning Services – TFTP2with Scope Options:
o 066 Boot Server Host Name =tftp.pvslab.com
o 067 Bootfile Name =ARDBP32.bin
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With the TFTP – GSLB option the DNS server must be configured with a Name Server for the
NetScaler ADNS service, a „gslb‟ subdomain, and an alias directing queries for the „tftp‟ name to
it.
Configuration
Screenshot Description
Configure DNS Server
Open the Windows Server Manager
Select the DNS Server Role
Right-click on the pvslab.com domain entry and select "New Delegation"
o Click: Next
o Enter: gslb
o Click: Next
Select Add Name Server
o Name: ns1
o Select: <Click here to add an IP Address>
o IP: 192.168.0.94
o Click: OK
o Click: Next
o Click: Finish
Right-click on the pvslab.com domain entry and select "New Alias (CNAME)"
o Alias Name: tftp
o FQDN: tftp.gslb.pvslab.com
o Click: Ok
See Appendix B - Reference Documentation for more information regarding installation
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Appendix A – Environment Details
Component Details
Provisioning Services Version 5.6.2
XenServer Version 5.6_2
NetScaler VPX Version 9.3-51.5
Windows Server Version 2008 R2
Vyatta Router Version 2.6.35-1
Appendix B – Reference Documentation
How to Add DHCP PXE Options to Microsoft DHCP Server
http://support.citrix.com/article/CTX115094
Requirements for Internet Hosts -- Communication Layers
http://datatracker.ietf.org/doc/rfc1122/?include_text=1
The Cable Guy: Strong and Weak Host Models
http://technet.microsoft.com/en-us/magazine/2007.09.cableguy.aspx
Provisioning Server High Availability Considerations http://support.citrix.com/servlet/KbServlet/download/18737-102-
445549/Provisioning_Server_High_Availability_Considerations2.pdf
Installing Windows Server 2008 DHCP Server http://www.windowsnetworking.com/articles_tutorials/How-to-Install-Configure-
Windows-Server-2008-DHCP-Server.html How to Add DHCP PXE Options to Microsoft DHCP Server
http://support.citrix.com/article/CTX115094
Using Provisioning Services Boot Device Manger with XenDesktop and XenServer http://blogs.citrix.com/2009/02/25/using-pvs-boot-device-manger-with-
XenDesktop-and-XenServer/
Using the Manage Boot Devices Utility http://support.citrix.com/proddocs/topic/provisioning-56/pvs-boot-devices-
utility.html
Vyatta Router – Quick Start Guide http://www.vyatta.com/sites/vyatta.com/files/pdfs/Vyatta_QuickStart_R6.1_v02_
1.pdf
Citrix XenServer - Quick Start Guide
Page 36
http://docs.vmd.citrix.com/XenServer/5.6.0fp1/1.0/en_gb/QuickStartGuide_BasicVersion.html
Citrix NetScaler VPX Getting Started Guide - Release 9.3 http://support.citrix.com/article/CTX128668
Provisioning Server and Citrix License Server Interaction FAQ http://support.citrix.com/article/CTX117378
Redundancy and Scalability for TFTP using NetScaler Direct Server Return
http://blogs.citrix.com/2010/11/11/redundancy-and-scalability-for-tftp-using-
NetScaler-direct-server-return/
Configuring Load Balancing in Direct Server Return Mode
http://support.citrix.com/proddocs/topic/NetScaler-load-balancing-93/ns-lb-
usecases-dsrmode-con.html#ns-lb-usecases-dsrmode-con
Load Balancing TFTP – Anything But Trivial
http://blogs.citrix.com/2011/05/02/load-balancing-tftp-anything-but-trivial/
Citrix NetScaler Networking Guide
http://support.citrix.com/servlet/KbServlet/download/27520-102-
659875/NetScaler-Networking-Guide.pdf
Using a NetScaler Appliance in the Use Source IP Mode
http://support.citrix.com/article/CTX117346
Does Use Source IP Mode Work in a NetScaler One-arm Mode Deployment?
http://support.citrix.com/article/CTX110459
FAQ: The USIP Address Mode of the NetScaler Appliance
http://support.citrix.com/article/CTX121974
How to Load Balance Trivial File Transfer Protocol Servers
http://support.citrix.com/article/CTX116337
How to Configure the Direct Server Return on a NetScaler Appliance
http://support.citrix.com/article/CTX110501
High Availability for Desktop Virtualization
http://support.citrix.com/servlet/KbServlet/download/21773-102-
650177/XD%20-%20High%20Availability%20-%20Implementation%20Guide.pdf
How to Add DHCP PXE Options to Microsoft DHCP Server
http://support.citrix.com/article/CTX115094
Page 37
Revision History
Revision Change Description Updated By Date
1.0 Document complete Matt Brooks – Principal Consultant Nicholas Rintalan – Sr. Architect
December 1, 2011
About Citrix
Citrix Systems, Inc. (NASDAQ:CTXS) is the leading provider of virtualization, networking and software as a service
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and Citrix Online Services product families radically simplify computing for millions of users, delivering applications
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