NetBoot across subnets with a bootpd relay
Hello Apple Community!
I've got 4 subnets at my school, each with various Macs around campus. I have a Mavericks server on each subnet currently, each with their own NetBoot images. It's a pain to keep everything updated. I can get a single client Mac (pre-2011) to boot across subnets using the bless command, but that's not really a viable solution for us to run a bless command on each client every single time we want to netboot. So far, the solution has been just to have dedicated netboot servers on each subnet, but I know there has to be a better way.
This article (OS X Server: How to use NetBoot across subnets - Apple Support) describes three different methods for netbooting across subnets, but two of them are not really viable for us. Those involve reconfiguring the network to allow BootP data to pass across subnets or configuring one server with multiple network connections, one for each subnet. However, option #2 describes configuring a bootpd relay. Based on my reading, this sounds like exactly what I need. However, I can't find any good documentation to walk me through setting it up.
I've thoroughly read the bootpd man page, which has had me editing the /etc/bootpd.plist on multiple servers. This hasn't gotten me very far. My clients still don't see the remote NetBoot server. It seems like the relay is supposed to redirect broadcasts from the remote Netboot server, through a local NetBoot server to the client. But I have no idea how to make this work.
Could someone please give me more guidance on what I'm supposed to be doing here? I'd like to host a single NetBoot server and have any client on any subnet be able to option-boot to see the NetBoot startup options (I have multiple NetBoot images, from Apple Service Toolkit to DeployStudio and Mavericks/Yosemite installers in between). Even if I could get it to just netboot to one default source (AST), I could deal with that. I'm also happy to host multiple NetBoot servers, but with all my NetBoot images in one location. I'm stumped in this multiple subnet environment and I need help. Please help.
Mac mini, OS X Server, OS X 10.9.4 with Server 3.1.2 running on a Mac mini