How To: Configure PXE services in LDMS 2016.3 or higher

What's new in LDMS 2016.3?

After upgrading to LDMS 2016.3 you may find PXE booting is not working as expected.   In 2016.3 LANDesk introduces Self-Electing PXE Services which is a major change and improvement to the way PXE representatives are deployed.  LANDesk will automatically elect and manage PXE reps for each subnet.  No longer will you need to manually deploy and remove PXE reps via Software Distribution packages.  While this new method has many advantages over the previous method, it will require some configuration before PXE booting will work properly.

You will notice that ALL Windows agents have a C:\Program Files (x86)\LANDESK\PXE folder (<18MB), also you will notice that if an agent has ever been elected as the PXE Rep it will have the LANDESK PXE Service, and LANDESK PXE MTFTP service installed. However, if the client is not the acting PXE Rep they will not be running. This is to facilitate the Self-Electing Services management of the PXE Rep on a given subnet. Once a device becomes a PXE Rep it will automatically download the boot.wim (~315MB) and boot_x64.wim (~420MB) files. These files will remain on the client even if a new PXE Rep is elected and this client is no longer acting as the subnet's PXE Representative. This can equate to around 750MB of disk space on current and previous PXE Reps.

Also in 2016.3 the NetBoot services offered by the LANDESK PXE Rep have been greatly improved for better more consistent performance. For information about how to configure PXE Representative to offer NetBoot Images to Macinstosh clients as well please see Configuring PXE to Deliver NetBoot Services in LANDESK 2016.3

Self-Electing Subnet Services

For the purpose of this guide we are dealing with the PXE Service section of SESS and we will focus on that aspect.

Self-Electing PXE Services

When configured and enabled, your managed clients will automatically elect a PXE representative in each subnet.  If the elected PXE rep is turned off, damaged or stops responding, a new PXE representative will automatically be elected, usually within 1-2 minutes.  The necessary PXE software is now included with the standard agent install, but is turned off by default.  As you setup PXE services, you will determine which devices are available to be used as PXE reps and which subnets allow PXE booting, and then LANDesk will take over and automatically elect a PXE rep in each subnet.  LANDesk can dynamically reassign additional PXE reps if the previous PXE rep stops functioning.

Configuration

To setup Self-Electing PXE Services, we will configure Client Connectivity settings as well as the PXE Service within Self-Electing Subnet Services.

Client Connectivity

• You will notice a new menu in Client Connectivity agent settings called Self-electing subnet services.  Select the PXE service submenu and check the box to Enable PXE service:
  
• This setting is where you will specify which devices are allowed to be selected as PXE reps.  When this setting is enabled, all devices to which this client connectivity setting applies might at some time be elected as the PXE rep. 
  
  If you wish to exclude devices from being elected as the PXE rep, you will assign them a different Client Connectivity setting, in which the checkbox is NOT checked.

Self-electing PXE Service

• On the core navigate to Configuration -> Self-electing subnet services -> PXE Service:
  
• Within this new dashboard you will configure whether PXE booting is allowed on a subnet by subnet basis.  When a particular subnet is enabled, and when Client Connectivity settings for devices in that subnet allow it, Self-Electing PXE Services will elect and manage PXE reps automatically
• You can view the state of each subnet and view which device is currently elected as the PXE rep

PXE Settings

• This is where you can customize PXE boot options on a subnet by subnet basis.  Select the subnet you wish to configure, and then click the "service settings" button on the toolbar:
  
• In the window that opens, you can configure Polling frequency, TFTP block size, allowed or denied devices by MAC address, and download source and bandwidth settings for the WIM:
  

Polling Frequency

• This setting determines how often the elected PXE rep on the subnet should check for updated settings and WIM files.  The default is 15 minutes.  If you change your boot.wim be aware the PXE rep will not 'see' the change until it polls for changes again

TFTP block size

• This setting allows the wim files to be downloaded much more quickly, especially the boot_x64.wim.  The default size is 16384 for ia32 and 65464 for x64
  
  Be aware that some systems, particularly VMWare, require a block size of 1456, and your WIM images will not download if this setting is configured for a larger block size

Allowed and Denied

• Allowed specifies that the list of provided MAC addresses are the only devices on the subnet allowed to PXE boot
• Denied means all devices not on the list, but on the subnet, will PXE boot

WIM Downloader Settings

• In this section you can allow the WIM images to be downloaded from Peer, Preferred Server, and Source, or any combination of the three
• The WIM image must be available on the peer or preferred server and it must pass a hash check before it can be downloaded
• You may also elect to limit the WAN or LAN bandwidth used when downloading the WIM.  This is a selection of how much available bandwidth to use, not how much total bandwidth

Troubleshooting Self-Electing PXE Services

For some common troubleshooting steps and log information please see this document:
How to Troubleshoot Self-Electing PXE Services