Can Ethernet-only KVM switch be used to image via PXE?

Tripp lite Netcommander b072-016-1-ip 16...
October 27, 2017 at 10:24:51
Specs: Windows 10, Intel i7-6700T
Hello all,

I work for a large annuities company, to which we typically image anywhere between 20-50 computers per week for deployments, swaps/breakfix repairs.

We currently use a 16-port KVM switch that connects to each node via VGA for video signal and USB for keyboard/mouse input. Ethernet leads to each as well for PXE. However, as you can imagine, this creates quite a mess, especially when the switch, along with the nodes, are all sitting on small shelves on a shelving unit - not ideal to say the least.

The model of the current switch is a Belkin OmniView PRO3, that gets daisy-chained to another if more ports are needed.

I've decided to have our facilities team to remove all the shelving units associated with imaging, and to replace them with large ergonomic desks that are very wide. I've built a few racks out of wood that will house our various models of laptops and thin desktops, to increase space utilization.

My question is, can a KVM Ethernet-only switch (no VGA or USB inputs to the nodes) provide the same functionality to perform imaging of OS via PXE boot, as would our original setup?

The switch I'm very interested in using is the following: TrippLite NetCommander 16-Port Cat5 KVM Switch 1U Rack-Mount (B072-016-1)

http://www.pcm.com/p/TrippLite-Swit...

My worry is that the video signal output to the switch from the nodes via Cat5e (and perhaps mouse/keyboard input from the switch to the console), won't display upon the several reboots that the OS deployment runs through via PXE.


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#1
October 27, 2017 at 11:24:39
My question is, can a KVM Ethernet-only switch (no VGA or USB inputs to the nodes) provide the same functionality to perform imaging of OS via PXE boot, as would our original setup?

I can't see why it wouldn't work. But.......and this is a big "but".........I've never tried it.

I have several of the same Belkin KVM's in some of my racks but we use something similar to what you're looking at using in the majority of our servers. The one I have is an Avocent AMX 5020

https://www.cnet.com/products/avoce...

Now keeping in mind I haven't tried to image servers using this type of KVM in conjunction with PXE technology, I can't see why it wouldn't work. The two network interfaces (assuming your KVM connects to an ethernet port as my Avocent does) are independent of each other as long as the imaging process doesn't kill the KVM interface, or change it in any way that prevents it from functioning correctly, it should all go smoothly.

You may have to tweak your image a bit to make it work correctly, but I can't see why it wouldn't work.

Just FYI, I don't image but I do know that a lot of servers connected to our Avocent have been imaged with Redhat using "kickstart" but I can't tell you much about that. I'm the network/data center/shop guy. So I plug the boxes in, hook them up and ensure they're connected to the proper VLAN(s) and that's all I do with them unless they have hardware issues at a future date.

It matters not how straight the gate,
How charged with punishments the scroll,
I am the master of my fate;
I am the captain of my soul.

***William Henley***


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#2
October 27, 2017 at 11:56:05
Question: If there is a dedicated build place, and it sounds like there is, why are you bothering with routing your PXE through a KVM? Wouldn't it just be easier to have your PXE server connected to a network hub that's limited to your build area?

How To Ask Questions The Smart Way


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#3
October 27, 2017 at 13:38:14
Oh my.........I completely missed the following:

My question is, can a KVM Ethernet-only switch (no VGA or USB inputs to the nodes) provide the same functionality to perform imaging of OS via PXE boot, as would our original setup?

bmwe46m3

I think you misunderstand how the ethernet KVM works. While I'm not certain with the device you're looking at I can tell you the Avocent I'm using requires an adapter which you plug the network cable into and that in turn connects to the video port and USB/PS2 port(s) of the computer. This is what the USB adapters I use look like:

https://www.google.ca/search?q=avoc...

These adapters preclude you using the same ethernet cable for anything else. You would in fact require two network interfaces in every computer in order to use both the KVM and your PXE NIC at the same time. It's worth noting that the Avocent ethernet KVM I use does not require any kind of TCP/IP settings anywhere. Each adapter has an ID number which once connected properly appears in the management console. This can be changed to a name and it is what's assigned to the appropriate admin(s) It's all "IP-less" and connects directly from the Avocent switch (not a normal network switch) directly to the computer via an ethernet cable.

Unless it's like a "remote KVM " (ie: HP's iLo and Dell's DRAC) which in your case would require a remote KVM card installed in each device you wish to connect to it. I've worked with both and prefer the remote KVM method as the admin can access said server(s) from their own desktop. This saves a lot of running around.

As far as I know, there is no other option. At some point you have to have something that provides access to the keyboard and video or the KVM is not going to work. Without access to the video, how could you see what you're doing? Without K/B access, how could you do anything like initiate commands, configure an interface or flash BIOS etc etc? You have to have video and K/B access. An internal "remote KVM" card does all that for you and you plug your ethernet cable into that device. But opening each box to plug a card in seems like a lot more work than your Belkin. I suspect the Tripp Lite device has adapters like I use which would simplify things over installing a card every time.

I would suggest you contact Tripp Lite and ask them about it. I had another quick look at the link you posted and it didn't say anything about how you get video and K/B access, just that it connects via ethernet.

It matters not how straight the gate,
How charged with punishments the scroll,
I am the master of my fate;
I am the captain of my soul.

***William Henley***

message edited by Curt R


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#4
October 27, 2017 at 14:08:07
Typically you use something like this on the server end: http://www.42u.com/raritan_cim.htm

Tripp Lite's product page suggests as much as well, "System Requirements: The Tripp Lite B078-101-USB-1 or B078-101-PS2 Server Interface Module must be used to connect a computer/server"

The better ones (Raritan) connect to your network, so you can access server consoles from your desk. They also have an option to mount an ISO, and I don't see those features on the Tripp Lite.

How To Ask Questions The Smart Way

message edited by Razor2.3


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#5
October 29, 2017 at 08:18:00
The better ones (Raritan) connect to your network, so you can access server consoles from your desk

The OP's present solution doesn't allow remote KVM either and if they have the budget for it (and haven't actually purchased the Tripp Lite product yet), a Raritan like you describe would be his/her best bet since it does allow remote KVM access.

The Avocent we have is old and not capable of remote KVM access. It requires users to login to a console created especially for that purpose. I suspect the OP's Tripp Lite solution is the same. Our Avocent was in place before I started working there 12+ years ago. We're moving completely away from that to built in remote KVM access. If a server has an issue, I wheel my "crash cart" (Monitor, K/B & mouse) over to the rack. If I can't fix the server in-place, I dismount it from the rack and put it on the bench in my shop.


It matters not how straight the gate,
How charged with punishments the scroll,
I am the master of my fate;
I am the captain of my soul.

***William Henley***

message edited by Curt R


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#6
October 29, 2017 at 08:29:52
Well, the best setup, and depending on the circumstances the cheapest, would be to have a PXE server either on the network or isolated to a build subnet, and have the build scripts do all of the routine configuration. Do the scripts well enough, and the build process becomes inserting blank HDD(s), connecting the power and KVM, powering the box up, and coming back after lunch to do any final box specific config. But to justify the time investment, you tend to need a dedicated build team comprised of people paid more than interns.

EDIT: I'd say Raritan really shines when you're working on a server geographically distant from you, but I tend to just use SSH, PowerShell, and MSTSC, because the latency sucks. So I end up only using KVM because the system can't reach the network, or I because need to fudge around with a BIOS.

How To Ask Questions The Smart Way

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#7
October 30, 2017 at 08:15:24
Thanks guys for your feedback. I guess I was trying to garner feedback from using an Ethernet-only, remote capable KVM switch to see if the imaging setup could be alleviated of so many cables/wires from having to connect VGA, USB keyboard & mouse, along with ethernet from PXE, as I have not used one before.

I did notice the adapter associated with the Tripp Lite KVM, but thought that was simply for the console. For some reason or another, my mind had settled on the notion that using an Ethernet-only KVM switch could simplify the cable management, because of video even being capable of transferring via Ethernet these days. I misunderstood the technology at-hand, and will re-examine.

The PXE servers are in-house in a cooled room built especially for rack-mounted server storage, I do not have access to this room, only very certain people do. I'm an IT infrastructure specialist, so I do a wide range of Desktop Support/VIP Support and Engineering work, used to be the Service Desk before these roles. Ethernet from the servers routes to a managed 24-port switch, to which then distributes to the imaging slots/stations. This does not include the wiring routing from the KVM switches to the stations as well. Again, it becomes quite a mess, but I think the main reasoning behind this is because of the lack of space I can access behind the shelving units to perform appropriate cable management.

Thank you again everyone for all of this information. It seems I may need to stick with Ethernet and USB/VGA setup still, but perhaps will be able to cable manage better with the new setup using desks instead of shelving units.

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#8
October 30, 2017 at 08:27:28
Myself, I don't do any imaging of PC's or servers. I'm strictly network, data center and shop. Servers are done by the admins and PC's by out PC group. We don't do anything like the numbers the OP was talking about or I suspect they gang in our PC department would likely setup something like what you're talking about. They already kind of do, only without the PXE server.

I set them up with a managed switch in their department. They purchased their own switch because (to quote the one member of that department) "Your switch has noisy fans" Since it's actually that department's property I configured it and added it to the network, but they manage port changes on it. The only thing they're not allowed to do is make changes to that switches uplink port. If they do, the switch goes away and either they do without, or I put one of my "noisy" in their and they're not allowed to manage it. We have many client subnets and this arrangements allows them to finalize the image on the subnet it's ultimately going to be on.

There's a chance we may upgrade the old KVM's and if we do, I'll definitely be looking into the Raritan's because remote KVM is going to be instrumental in a lot of our future IT plans for the data center. I think I mentioned previously that all our new servers have built in remote KVM technology but we may get into hosting and colocation so that would definitely be a benefit if we do.

It matters not how straight the gate,
How charged with punishments the scroll,
I am the master of my fate;
I am the captain of my soul.

***William Henley***


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#9
October 30, 2017 at 09:17:35
bmwe46m3: Yeah, given your setup, the only other suggestion I could make is to get those special KVM cables that bundle USB and VGA together in the same wire bundle, but you can get the same effect with your existing cables and a bunch of cable ties.

Curt R: Funny enough, we're moving away from Raritan as we take on more blade servers, since the only console connection is through a dongle (purchased separately) you attach to the front. I doubt it'll be an issue you'll encounter with collocation, but it might be something to keep in mind. Especially if you go the, "we'll buy our recommended hardware for you," route.

How To Ask Questions The Smart Way


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#10
October 30, 2017 at 14:33:30
bmwe46m3

The big plus about KVM over ethernet is getting rid of the big fat cables in favor of a network cable and a very small adapter. If you do work it out, you'll only have power and two ethernet cables running into the PC's. Well, one ethernet cable will go into the adapter but considering how small they really are it's a noticeable difference where space is tight.

I do a lot of cable management as part of my work and I would think shelves would actually be better. You could get some plastic cable management raceways and screw them onto the shelving units horizontally. I'm thinking of something like this:
https://www.google.ca/search?q=cabl...
or this:
https://www.amazon.ca/StarTech-com-...

They come in different sizes and something maybe 3" spare might be enough to do the trick for you. It's a PITA, but once you've finished the cable management it's neat, clean and easy to work around.

Razor2.3

I'll definitely keep it in mind in the future.......thanks!

It matters not how straight the gate,
How charged with punishments the scroll,
I am the master of my fate;
I am the captain of my soul.

***William Henley***


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#11
October 31, 2017 at 09:26:14
Hmmm... do you think a USB PXE-capable Ethernet adapter (such as a Startech) would be able to provide the 2nd NIC for an Ethernet-only KVM switch? Then the primary Ethernet NIC can be for the switch, or vise-versa.

Perhaps the best thing will be to purchase one on account, test out the functionality, then return it if it doesn't work out.

Thanks again guys.. I'll report back on this just in case anyone is curious.


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