Multiple Netboot servers on one subnet

[akanuteh]

I want to have multiple Netboot servers one subnet. How do one go about that. On the other hand, if I use one Netboot server, will that support 300 clients at the same time.

[andrewseago]

Like 300 clients all netbooted at one time?

[John_Wetter]

Are you simultaneously imaging 300 clients? Netboot or NetInstall? For imaging, I'd use the JAMF appliance and throw some real hardware behind it before I'd go with 2 servers. Of course, the network is really going to be the limiting factor here unless you're planning on using a mini or something where the HDD is going to be the limiter.

[acidprime · Accepted solution]

I would recommend no more then 50 per server most days. You can load balance net boot images by creating index numbers of 4096+ which is just to say if you have multiple net boot servers on the same subnet hosting images and your images are indexed at say number 5000 then the client will do the load balencing by the first to respond ( assuming your N key booting ). If you need more granularity I have an example load balancing script with Cocoa UI that might want to check out if you really need to do this without the Apple Scheme. In your case as well its also worth nothing that at 300 if your doing erase and installs you might look into multicast imaging.

Mentioned in my presentation here ( with script downloads link)

http://documentation.macsysadmin.se/2011/2011doc.html

and on my blog here

http://www.wallcity.org/2011/02/fun-with-servermgrd-python/

[akanuteh]

I have one more question. Can I use JAMF appliance for this. i.e. having four of them on the same subnet.

[acidprime]

I don't see why this would be an issue as if they are have different IPs, everything else is broadcast so you should be fine, however I have not done this specifically with the VM as it just came out. Though be aware if your trying to do this that net boot is only half your issue, you also need enough bandwidth on your distribution pont to handle as many net booted clients as you are imaging. i.e. Each client thats net booted is a file sharing client for your distribution point. If your unicasting (i.e. not multicasting ) each client is requesting a different I/O stream from your distribution point, in other words if client A is 20% through imaging he may be installing a Microsoft Office package, or maybe be requesting data block 20 of your disk image, but client B is requesting data block 35 or an Adium package installer. If your distribution point is being server'ed from a RAID, that helps, but you also have to consider that even some like a promise fibrechannel or thunderbolt external while capable of putting out 500MB/s is bottlenecked by the host its being re-shared on , thus with a single gigabit ethernet port you are only really getting 100MB/s or so. While you may be able to net boot many clients on the same time your distribution point will most likely be the same on the same subnet and will overload the distribution point boxes I/O.

[dhutchinson]

If I have 2 Mac servers on the network and want to load balance for imaging, does the index number for the image need to be the same on both Servers, or can one be 4096 and the other 4097?

Thanks

[tthurman]

I thought when you tried to run two NetSUS appliances on the same subnet, one would kill the other and only one would appear.

I could be wrong - but that's what I've seen in my environment.

[bentoms]

@dhutchinson to load balance, both will need the same image index, & it's value will need to be between 4096-65535

[bentoms]

@tthurman You can't load balance NetSUS or have multiple NetSUS's broadcasting to the same clients or a NetSUS broadcasting to clients where another NetBoot server is.

[calumhunter]

You can't load balance NetSUS or have multiple NetSUS's broadcasting to the same clients or a NetSUS broadcasting to clients where another NetBoot server is.

@bentoms is that a specific NetSUS limitation?

My experience is that its no problem to have multiple netboot servers on the same subnet (not load balanced) i.e. with ID's under 4096
These netboot servers might host different NBI's i.e. BSDPy hosting an imagr NBI and a Mac OS X Server hosting a DS NBI

Both servers and clients all on the same subnet

[bentoms]

@calumhunter yep. NetSUS doesn't play well with others.