[HN Gopher] Show HN: TinyPilot - Build a KVM over IP using a Ras...
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Show HN: TinyPilot - Build a KVM over IP using a Raspberry Pi
Author : mtlynch
Score : 493 points
Date : 2020-07-23 13:56 UTC (9 hours ago)
(HTM) web link (mtlynch.io)
(TXT) w3m dump (mtlynch.io)
| cmer wrote:
| This is a game-changer! Thanks for all your work on this.
|
| Do you have any plans to allow controlling more than 1 computer
| remotely? I'd love to implement this in my homelab.
| mtlynch wrote:
| > _This is a game-changer! Thanks for all your work on this._
|
| Thanks for reading!
|
| > _Do you have any plans to allow controlling more than 1
| computer remotely? I 'd love to implement this in my homelab._
|
| Right now, I can't think of a way to do this. The Pi only has
| one USB OTG port, so I don't know of a way to share that among
| multiple machines.
|
| A friend suggested an interesting solution of chaining
| TinyPilot together with a "dumb" multi-machine KVM that
| supports switching via hotkey. So it would go:
|
| TinyPilot -> legacy KVM -> server1, server 2, ...
|
| You could still use a web interface and hop between servers
| using keyboard shortcuts that the legacy KVM understands.
| cmer wrote:
| That's a really great and simple idea, actually. I might give
| this a try.
| dukoid wrote:
| I have given up on KVMs altogether and I am using the following
| approach now:
|
| - Most monitors have multiple digital inputs. Connect each
| computer to one of them
|
| - Use a USB switch keyboard and mouse
|
| - Before switching the USB switch, press the "lock screen" key
| combination and make sure locking the screen drops the video
| signal
|
| - After switching the USB switch, pressing shift should bring up
| the login dialog and re-activate video output. Since the monitor
| has just lost the signal in the previous step, it will scan the
| inputs and switch to the desired signal.
| jbob2000 wrote:
| I did this for a while, the problem is that there's really no
| such thing as a high-quality USB switch. They are all garbage
| and mess with USB devices in some way (at least at the consumer
| level).
| btgeekboy wrote:
| I have an old Belkin USB 2.0 switch from god-knows when that
| works beautifully. I use it to share a hub with a keyboard
| and mouse attached. I've given up trying to find a 4K60 x2
| DisplayPort KVM that doesn't suck.
| stamps wrote:
| I have this one[0] that works great.
|
| Wendell at Level1Techs does good work and there's even
| newer ones that can do 8k30.
|
| [0] https://store.level1techs.com/products/kvm-switch-dual-
| monit...
| ajford wrote:
| I couldn't find the details on their site, but do you
| know whether the 3.5mm audio jack is 3 or 4 pole? I've
| found that most KVMs have the 3 pole jack, meaning it
| just supports audio out, but I need 4-pole so my headset
| microphone works.
| bombita wrote:
| I have been using this at 4k60 (but 1 monitor) flawlessly
| for 8 months.
|
| https://www.startech.com/Server-Management/KVM-
| Switches/2-po...
| duskwuff wrote:
| Seconding a recommendation for Startech's KVMs. They have
| an _excellent_ USB stack which handles complex USB
| hierarchies flawlessly -- I 've successfully used mine
| with chained hubs, weird HID devices like Apple
| keyboards, and non-HID devices like disks, audio
| interfaces, and even stranger things.
| GordonS wrote:
| I switched from a KVM to a USB switch a few years back, and
| haven't had any real issues with it. I don't think it was
| expensive either, just a standard USB 3 switch with only 2
| ports. Occasionally it takes more than a few seconds after
| pressing the button for the switch to happen, but that's
| about it.
| BoysenberryPi wrote:
| This is my experience as well. I currently use a USB switch
| that I got off of Amazon for about 15 bucks. It typically
| "just works." Press the button, wait 2 seconds and my input
| devices have switched.
| TacticalTable wrote:
| Care to share it? The one I have will work for a few
| switches, then both Windows/Mac will eventually stop
| recognizing the port its connected to until a reboot.
| HEHENE wrote:
| I have been using one from IOGEAR (SKU GUS432CA1KIT) for
| the last 6 months and I haven't had a single problem with
| it.
|
| I use it to switch all of my peripherals (keyboard,
| mouse, wireless headset dongle, webcam, and mixer)
| between my desktop and my MacBook several times per day
| and have not had a single failure yet.
| JeremyNT wrote:
| > _I did this for a while, the problem is that there 's
| really no such thing as a high-quality USB switch. They are
| all garbage and mess with USB devices in some way (at least
| at the consumer level)._
|
| A lot of these things seem to "help" by inserting their own
| USB host device that acts as a proxy for attached USB
| peripherals. This allows them to do (ostensibly) useful
| useful things such as intercepting keypresses and responding
| to them (e.g. by switching to another input).
|
| Don't get one of those, get a _physical_ switch that just
| connects the leads to the correct port when pressed. I got
| this USB 2.0 switch (all you need for input devices) for $12
| [0]. I 'm sure there are others available with more ports,
| but this is all I needed.
|
| [0] https://www.amazon.com/gp/product/B01HV1N674
| weaksauce wrote:
| Yeah I second this. I have a physical usb switch to move
| keyboard and mouse over. It works flawlessly.
|
| Though, I also use a KVM to switch over the video but it's
| separate.
| tyingq wrote:
| That's handy for the KVM part, but this is mostly about KVM
| over IP.
| TaylorGood wrote:
| I just bought a PiBookPro (1) that I discovered on Twitter.
| It's a laptop shell for RPi at $80. Kind of a wild backstory
| but hard to beat that $
|
| 1) Http://pibookpro.com
| derefr wrote:
| I feel like the ideal here would be for there to be a
| Thunderbolt/USB4 display which has multiple Thunderbolt
| "source" ports, and _also_ USB-C connectors for peripherals,
| where the display itself is acting as a USB controller
| available over Thunderbolt-PCIe, with the USB-C sockets
| attached to said USB controller. Change the input on the
| monitor, and the USB-controller PCIe card in the display would
| be hotplugged out of one computer and into the other.
|
| Even more ideally, the display would _also_ have a built-in
| Bluetooth controller that stays active regardless of the USB
| controller 's attach state, such that Bluetooth peripherals
| could be paired _to the display itself_ rather than to the OS
| (i.e. you 'd manage the pairings through the OSD of the
| display); and then these devices would be presented through the
| display's USB controller as always-on direct-attached USB
| devices -- much like VM hypervisors present host-attached
| Bluetooth HID devices to their VM guests. (As a side-benefit of
| that, as long as the computer's BIOS understood Thunderbolt
| well-enough to display anything during boot, then even
| Bluetooth peripherals would also work during boot.)
| monadic2 wrote:
| I've just given up on Bluetooth for rapid device switching.
| It's too time consuming to be figuring out which device your
| headphones are attached to & disconnecting/reconnecting to
| resolve, especially e.g. when someone calls you. Wires are
| very, very easy to read and debug.
|
| I have AirPods but will only pair them to my phone.
| ryanar wrote:
| AirPods are the first blutooth type device that I switch
| all the time. If I am hooked up to my phone and connect on
| my Mac, instantly switches, if I am paired to my Mac and
| get a call on my phone and accept it, it opens a menu
| asking if I want to use airpods, tap that, instant audio /
| mic. The switching is so seamless and it makes the tech
| phenomenal for me.
| philippantoni wrote:
| The LG ultrawide monitor with Thunderbolt that I have from a
| couple years ago (34UC97) mostly does this -- It has a two-
| port USB hub which I use for my mouse and keyboard, which it
| routes either through the Thunderbolt interface to my MacBook
| or a separate USB cable to my PC, depending on whether
| Thunderbolt or one of the DisplayPort/HDMI display inputs is
| selected.
|
| (I'd guess their newer models work similarly but I haven't
| confirmed.)
| burnte wrote:
| Oy! I've been designing a HAT for a year to do this, but it would
| take VGA rather than HDMI. You've done well! :D
| RealStickman_ wrote:
| Funnily enough I'm waiting for my hdmi to usb capture card to
| arrive so I can play on my PS3 while also having the option of
| switching back to the desktop instantly.
| swiley wrote:
| That has to add a lot of latency.
|
| Although honestly I think some of the latency complaints by
| gamers are a little much. Personally I have a Bluetooth
| mouse/keyboard connected to my desktop with a super duper cheap
| projector pointed into the living room and can play FPS games
| on it just fine.
| RealStickman_ wrote:
| It probably won't work. Though I think it could still be a
| fun project. Maybe I'll use it in the same way the author
| does in the end.
| ctas wrote:
| It has a lot of latency indeed. I tried the raspberry as a
| Steam Link alternative, but as far as I know the ethernet
| port is not suitable (?). I've also read that it actually
| gets worse if you plug in any USB peripherals. Correct me if
| I'm wrong though.
| swiley wrote:
| Yes the Ethernet port is on USB so you're sharing (the
| already small) bandwidth between that and all the
| peripherals.
|
| This may have changed with the pi4 though.
| yetanta wrote:
| Using a timer on a screen to SEE latency. Why did I not think of
| that?!
| mtlynch wrote:
| Thanks for reading!
|
| I got the idea from danman, but his setup is much cooler than
| mine:
|
| https://blog.danman.eu/new-version-of-lenkeng-hdmi-over-ip-e...
| cerberusss wrote:
| Fantastic project. Amazing how you overcame each obstacle, and
| very well written to boot. Kudos.
|
| Quite funny how you brought 1000 ms latency down to 200 ms. I
| wonder how this compares to iDRAC and that Raritan device.
| mtlynch wrote:
| Thanks for reading!
|
| Yeah, it was kind of like the perfect difficulty level for this
| kind of project. If it was two months of work to get it working
| at all, I probably would have gotten discouraged, but it worked
| out that every couple weeks I was rewarded with a breakthrough
| that substantially improved the latency until it was finally a
| practical tool.
| cm2187 wrote:
| I don't know about iDRAC but I used raritan a bit for some home
| projects and it's not super fun. I couldn't connect it on HDMI
| when the server was already running, it had to be connected
| before the boot. For both VGA and HDMI, it sort of works, there
| is a clunky but functional java desktop application, the screen
| is often off by a dozen pixels (part of the screen hidden) and
| the pointer too.
|
| For new servers, I just buy a supermicro motherboard with IPMI
| and stop worrying. You can set up an IP based firewall within
| IPMI, so that only a handful of IPs can even connect, plus a
| very strong password, and I am not too worried about exposing
| it to the WAN (I know it's not a great idea but I don't know
| any alternative that doesn't require another U in a
| datacentre)..
| EvanAnderson wrote:
| I've used virtually all of the iDRACs. They're probably in that
| 200ms area (based on my gut feeling w/ no empirical
| measurements). They've been fairly responsive in my experience.
| tinco wrote:
| I manage a machine that has an AST2500 (competitor to iDRAC in
| smaller vendors like Gigabyte, it rocks), and I didn't notice
| latency, so it's probably under 200ms.
| numpad0 wrote:
| Most iDRAC type products actually use that same Aspeed
| ASTxxxx with vendor firmwares. If a server reports "Matrox
| G200e" as display adapter it's it.
| captn3m0 wrote:
| Was stuck with latency issues on a unrelated streaming project,
| thanks for writing about ustreamer - going to try that out.
| znpy wrote:
| the best thing in this article is the immediate link named "I
| don't want your life story; just tell me how to build it "
| mtlynch wrote:
| Haha, that was inspired by my experience of searching cooking
| recipes online.
| erikig wrote:
| Which begs the question - which cooking recipes start off
| with a biography of the author? Now I want to see those!
| jbj wrote:
| I use barrier on my raspberry pi, and have a keyboard shortcut to
| pick wich machine receives the keystrokes and mouse movement.
| Additionally to this keyboard shortcut, I also need to click a
| button on my monitor since it can receive hdmi from multiple
| machines.
|
| It works great, If I could get it done with only a keyboard
| shortcut, I would only pick this solution if it does not induce
| additional lag.
| naggie wrote:
| Brilliant idea. I have an idea to extend this!
|
| 1. A relay to reset the PC like iDRAC/iLO
|
| 2. 2 dual pole relay to move a USB flash drive to and from the PC
| it's connected to, in combination with (1) you could then boot
| ISOs remotely by dd-ing the ISO to the flash drive and then
| connecting it to the host PC with a relay
| [deleted]
| agwa wrote:
| It should be possible for the Raspberry Pi to emulate a USB
| flash drive using the OTG connection, though I'm not sure if it
| can emulate a keyboard and a mass storage device at the same
| time. It would be a very valuable feature for sure.
| Nexxxeh wrote:
| Alternatively, just use a microcontroller for the USB HID
| stuff, and talk to it via BT/WiFi/40-pin header.
| tmzt wrote:
| The kernel at least supports that, through the gadgetfs
| filesystem.
| bronco21016 wrote:
| The GPIO should easily be able to handle doing a reset by
| connecting with jumpers directly to the motherboard. I guess
| there may be some circuitry required... I'm not positive on how
| the standard motherboard pins work.
| tmikaeld wrote:
| Raspberry 3B is too slow for this?
| Nexxxeh wrote:
| More likely the lack of OTG being an issue, as elsewhere in the
| comments the author showed the CPU usage of the Pi 4. It's not
| even making a dent. It's super low overhead. I'd be surprised
| if it maxed out a 3B.
| Jaruzel wrote:
| I have a similar solution in place. For _reasons_ ... I have a
| machine that is 100% locked down by the client. I cannot install
| software on it, nor does it have any sort of remote access tools
| installed on it. To keep my work space clear, and negate the need
| for second monitor (as I need to be able to see the screen of
| this machine AND my main machine at the same time), I use an
| Elgato CamLink HDMI dongle[1] to capture the video output of the
| machine, and I use VLC to display it in a window on my main
| desktop. I use a bluetooth keyboard and mouse combo to control
| it. The latency on the video capture is very low (it doesn 't
| feel any more laggy than a normal remote sesson), and as an added
| bonus I can screen capture the video stream, which is really
| useful for documentation. The CamLink is locked at 1080p, so as
| long as the machines desktop resolution matches that, I get a
| very crisp picture. I've been using this setup for almost two
| years now, on a daily basis with no issues.
|
| --
|
| [1] https://www.elgato.com
| lxe wrote:
| Oh man, the video latency woes. I've been going through the same
| motions trying to get minimal-latency stream-to-browser from an
| Amcrest (Dahua) IP camera. Their app and cloud services leaves
| much to be desired, so I tried to roll my own. They cameras send
| h264-encoded stream over rtmp but also through some kind of
| custom HTTP protocol which their browser app (requiring a scary
| binary native plugin) decodes, but it's challenging to reverse-
| engineer.
| louwrentius wrote:
| I respect this effort, I think it's a great accomplishment.
|
| I think most people are better off building their own home (lab)
| server with a motherboard that supports IPMI (KVM over IP)
| natively.
|
| Supermicro (only brand I've experience with) or other brands that
| build server motherboards all include IPMI with HTML5 support.
|
| Doing so will save you a lot of trouble. Maybe you may not be
| able to run the kind of hardware you want, but it's all a
| tradeoff. You have to choose.
|
| I have HP Microservers (quiet) and a Proliant (loud) all with ILo
| (HP IMPI) and it's awesome.
| grosswait wrote:
| I just finished building a Pi KVM about a month ago using project
| https://github.com/pikvm. Has been great so far.
| mtlynch wrote:
| Yeah, I'm really impressed with that project and love Max's
| work! There's a bit of a barrier to entry though, as it
| requires you to compile the OS yourself. My goal with TinyPilot
| was to create something that's easier for newcomers to install
| and simpler for me to reason about.
| pdimitar wrote:
| I'll use the opportunity to ask for a KVM switch help here if
| that's not breaking the board's rules (and I feel it's related to
| the topic):
|
| I got a company laptop recently and bought an Aten CS782DP KVM
| switch so I can reuse my gaming PC's monitor on it (using
| DisplayPort 1.4 cables). But when using my gaming PC the display
| now flickers very often when gaming and it's driving me crazy.
| Some people said it's the length of the DP 1.4 cables (they are
| very short though, <1m), some even say gas spring chairs
| introduce signal disturbance (wtf?), others say make sure the DP
| 1.4 cables don't touch any other cables.
|
| In any case: would a KVM switch like the one in the post help? I
| suspected NVIDIA's G-Sync but turning it off for several days
| made no difference. :(
|
| For the record, the display runs at 144Hz in both Win10 and
| Ubuntu. But it only flickers in Win10. The only thing that comes
| to mind is that the miniDP-to-DP cable that runs from my PC's
| videocard to the KVM switch is no good -- but not sure. I sadly
| can't use the KVM switch's DP-to-DP cable because my videocard
| only has miniDP on its rear.
|
| Anybody had similar struggles in the past?
| techntoke wrote:
| Have you tried lowering to 60Hz in Windows to see if it helps?
| What about another switch?
| pdimitar wrote:
| In the very few games I play 60Hz is way too low so I haven't
| attempted it at all -- I want the maximum Hz/FPS.
|
| As for another switch, I am open to ideas if you have them.
| In my local market I was only able to find like 2-3 of them
| [that support DP 1.4] and they are all north of $250 -- which
| I don't mind but it would be non-pleasant to buy 5+ of them
| just to experiment.
|
| Maybe my requirement for DP 1.4 is silly though. Maybe HDMI
| would be fine.
| techntoke wrote:
| My guess is that switch simply doesn't support 144Hz, so if
| it works at 60Hz then you have your answer.
| pdimitar wrote:
| They advertise 4K@60Hz and my display is at 2560x1080 @
| 144Hz. Math says my case should be supported but yeah,
| computer standards are often non-intuitive. I'll try with
| 120Hz and then 60Hz just to ascertain limits as you
| suggest. Thanks.
| systemBuilder wrote:
| This guy has apparently never heard of lynx browser. He wasted
| $40 and a lot of time because of that!
| x87678r wrote:
| This looks awesome. I was looking for a solution like this last
| year. I budgeted a few hundred bucks but couldn't find anything.
| Ideally would have a way to handle a few different boxes.
|
| I did see something called Intel AMT, part of Intel vPro.
| https://www.howtogeek.com/56538/how-to-remotely-control-your...
| Does anyone have experience with this? (I have AMD box so doesn't
| help me) - actually looks like AMD has similar
| https://developer.amd.com/tools-for-dmtf-dash/
| mixmastamyk wrote:
| Is it trustworthy, or full of backdoors?
| Haemm0r wrote:
| It works, however you need a non-free special client called VNC
| Viewer Plus [1]. Afaik it is Windows only. You can enable
| regular VNC protocol capabilities for AMT[2], but then you
| can't use the interesting stuff anymore.
|
| [1] https://www.realvnc.com/en/products/viewerplus/ [2]
| https://blog.michael.kuron-germany.de/2011/10/using-intel-am...
|
| //edit: link [2] added.
| tyingq wrote:
| This seems to show a reasonable option from Linux:
| https://www.cyberciti.biz/faq/remotely-access-intel-amt-
| kvm-...
| vetinari wrote:
| You can use meshcommander[1], which has a nodejs version that
| runs under linux and mac.
|
| Then you just have to pay attention to your certs (if you are
| using https), because browser policy will apply.
|
| [1] https://www.meshcommander.com/meshcommander
| an_opabinia wrote:
| I just set up AMT for a bunch of servers.
|
| It is possible but extremely tricky to set up AMT headless on a
| self built Intel. You basically need to press keyboard keys at
| the right time. Too challenging without a display.
|
| Devices don't load AMT configuration from USB by default unless
| a vendor configured them to. In which case the vendor just
| ships you AMT enabled in the first place.
|
| Better to just image the disk on a different computer.
| wolfhumble wrote:
| If a machine/server doesn't have built in IPMI, I am using an
| Adderlink Digital ipeps and control it that way 1). Apart from
| the built in RealVNC server, it also has HDMI video, USB and
| virtual media support among other things. I have no
| relationship with Adderlink, but I am a happy user of this
| product. Not cheap, but worth the price IMHO.
|
| 1) https://www.adder.com/en/kvm-solutions/adderlink-digital-
| ipe...
| cr3ative wrote:
| AMT is great. I use it with https://www.meshcommander.com/ -
| though learning how to provision the machine correctly in Admin
| Mode so it doesn't pop up a pin-entry screen on the remote end
| is "fun"!
| R0b0t1 wrote:
| vPro is error prone and may require multiple setup attempts. If
| you want to use it on anything but the same LAN there is a
| built-in VPN. If you can find anything about the AMD version
| I'd be interested, they don't seem to publish anything unless
| you are a partner.
| close04 wrote:
| Here are some AMD tools, docs are thin on the ground. [0]
|
| I have a boatload of Intel vPro machines spread throughout
| multiple countries (or the basement) and connect to them both
| via internet (mutual TLS authentication) and VPN. Never had
| any reliability issues at provisioning or operating. I had an
| old AMT v2.1 machine that was a bit unreliable, needed to be
| manually powered on once in a while or the remote connection
| wouldn't work.
|
| I wholeheartedly recommend Meshcommander [1] for this.
|
| [0] https://developer.amd.com/tools-for-dmtf-dash/
|
| [1] https://www.meshcommander.com/meshcommander
| wjdp wrote:
| Not tried anything like this before: looking at TinyPilot and Pi-
| KVM which one should I use?
|
| I'm happy doing some soldering. Is there anything that TinyPilot
| has that Pi-KVM doesn't?
|
| Has Pi-KVM added support for the HDMI dongle you used?
| mtlynch wrote:
| Thanks for reading!
|
| I'd say, in short, Pi-KVM is more feature rich, while TinyPilot
| is simpler and more approachable with less functionality.
|
| Pi-KVM has several nice features that TinyPilot doesn't yet
| have, including power management, mouse support,
| authentication, TLS, and USB storage mounting.
|
| TinyPilot has a quicker install. Pi-KVM requires you to compile
| the OS locally, which takes about an hour. If you've got a
| Raspberry Pi OS system (aka Raspbian) already, you can
| configure it for TinyPilot with two commands, and the install
| takes 5-10 minutes.
|
| One of my goals with TinyPilot was to avoid a requirement for
| soldering/jumper cables, but if you don't mind soldering, that
| might not matter much to you. Pi-KVM works without soldering as
| well, but the documentation assumes soldering/breadboards.
|
| I hope that there's space for both projects, and Max and I have
| talked about ways to potentially collaborate.
| mdevaev wrote:
| Pi-KVM can do all the same, and it also supports IPMI, VNC, and
| Mass Storage Device emulation. The only difficulty is that for
| the USB dongle to work, you need to add a couple of options to
| the config, because it's not yet supported out of the box.
| Everything else will work on its own.
| cptnapalm wrote:
| I tried something like this, but instead of a KVM, a remote
| "terminal" for multiseat in Linux. usbip worked fine, but I
| couldn't get video to work for a damn. The idea was to have the
| main computer stream video from one seat to the RP and act as a
| client for the keyboard and mouse attached to the RP using usbip.
| Had I been able to get the video portion to work, then next step
| would have been setting the RP to boot to a fullscreen vlc (or
| what have you) which displayed the gdm login screen from the main
| computer.
| rglover wrote:
| This is great, Michael :) One question before I buy...
|
| I'd like to use these to do development work like you suggested,
| too. Is the Hacker option the build with the best latency/least
| issues (set it and forget it)?
| mtlynch wrote:
| Thanks for reading!
|
| Honestly, the overhead from TinyPilot is so small that it's
| just a question of how powerful you want the device for other
| activities.
|
| Here's a screenshot I took earlier today on a Pi 4 with 2 GB of
| RAM. TinyPilot is streaming video over WiFi, and top shows that
| it's only using ~4% of CPU and ~2% of RAM:
|
| https://imgur.com/GadzDOr
| [deleted]
| ape4 wrote:
| Sorry to ask but what's it cost to buy a KVM over IP device?
| EvanAnderson wrote:
| You're not going to find a decent one sub $500. Used devices
| can be had for less, but most of the older ones I've seen use
| terrible Java-based clients that are a major pain to get
| running on modern browsers. For multi-device KVMs you usually
| have to figure in the prices for the individual interface
| module dongles that plug into each computer, too.
|
| StarTech makes a USB-to-KVM that looked promising to me, but
| it's still >$400: https://www.startech.com/Server-
| Management/KVM-Switches/Port...
| ape4 wrote:
| Thanks and that StarTech doesn't have HDMI. Maybe its cloud
| VMs that are removing the need for KVM over IP. I still want
| it.
| AaronFriel wrote:
| I wouldn't say cloud VMs have removed the need, they've
| just made infra admins have to live without it. For the
| most part it's fine on well supported and tested OSes but
| before the container/kubernetes revolution I managed some
| personal VMs with esoteric distros in various clouds and so
| many things have to go right for that to work. A bad update
| or install of grub, initrd, dhclient, a handful of system
| services and maybe systemd, or sshd and the machine is
| effectively dead. You have to attach the disk to another
| machine to debug it.
|
| A more extreme example was when I went down the rabbit hole
| of trying to set up remotely unlocked full disk encryption
| on a cloud, just to see what was possible. This was maybe
| 4-5 years ago. This involved a pre-boot environment that
| would run from memory only, packaged into an initramfs and
| used dropbear as an ssh server to accept a connection.
|
| I really, really wish cloud VMs had virtual KVMs. It turns
| out, it's really easy to mess this up, and when you do
| recovery is Non Trivial.
|
| The best I found was that Azure's cloud allows you to
| connect (read/write!) a virtual serial port via web
| interface so you can use the Linux serial console to
| recover. That was a game changer for playing with this. If
| dropbear failed to come up, I _at least_ got a shell into
| the pre-boot environment.
| rob-olmos wrote:
| Google Cloud also provides read/write serial ports over
| SSH: https://cloud.google.com/compute/docs/instances/inte
| racting-... -- but I think AWS still doesn't.
|
| One thing I've ran into was root not having a password
| since the cloud images are typically SSH key auth only.
| That was annoying when trying to fix something simple
| like iptables or entering maintenance mode for a disk
| check.
| AaronFriel wrote:
| Thank you! I wasn't aware this was possible back then.
| I'm glad they implemented this.
| ed25519FUUU wrote:
| I can't tell if the USB port that usually delivers power is the
| only one that supports "USB Device Mode" (USB OTG). Can someone
| confirm? If I could use _any_ port, then there would be no need
| for powering the pi with a serial USB adapter.
| radiowave wrote:
| From memory, this is correct. It's only the USB-C port that
| allows OTG operation. I remember a while back seeing someone
| selling a special splitter cable for the rpi4 which provided 2
| separate USB connectors, one for powering the rpi and one for
| attaching the pi as a gadget to a USB host port. But I can't
| remember where I saw it, and haven't been able to turn up a
| link to it.
| bsharitt wrote:
| Nice, I had thought about an HDMI capture device but plugged it
| in, played with it for about 5 minutes trying to tune out the
| latency(I'm not exactly and ffmpeg pro) and didn't make much head
| way. I was also using either a pi 2 or 3, so that maybe have been
| part of the problem too. I'm glad someone actually had the time
| to see it through and put together a solution. Having one of
| these would have been super useful the past few days when I was
| having kernel panics due to a failing root disk on my home
| server, but I had any spare monitors stored away because I'm in
| the middle of moving. I'll have to give this a look once I get
| all settled in again.
| martinmunk wrote:
| I've long considered creating a KVM IP thingie for VGA video with
| a BeagleBone Black. IIRC the PRUs (200mhz coprocessors) and the
| on-chip ADC should be fast enough to sample the video as-is, and
| have DMA access into main-cpu ram.
| dannyw wrote:
| Hey OP, I was reading your linked HomeLab article and you
| mentioned you'd rather have gotten a mobo with integrated GPUs
| next time.
|
| Actually, motherboards do not include integrated graphics, it's
| all in the CPU/APU. The mobo you linked would not provide
| graphics either.
|
| AMD unfortunately does not have a high end APU released to
| consumers right now (there are some 4000 series, but only to OEMs
| I believe). However, for a HomeLab setup, you might find a cheap
| GPU to be useful for many things (including hardware video
| transcoding).
| mtlynch wrote:
| Thanks for reading and for the note! I didn't realize that
| about display not being available on motherboards generally.
|
| I just built a new homelab server and ended up buying a
| separate GPU again. My new mobo is the SuperMicro
| MBD-X10DAL[0], which has no onboard display.
|
| [0] https://www.supermicro.com/en/products/motherboard/X10DAL-i
| cptskippy wrote:
| > Actually, motherboards do not include integrated graphics,
| it's all in the CPU/APU.
|
| You should probably qualify that as current generation. There's
| plenty of last gen Intel and AMD solutions with onboard
| dedicated graphics.
|
| I think the advent of GPU acceleration in servers and APUs for
| low end machines has impacted demand for these motherboards in
| current gen products.
| PaulKeeble wrote:
| I have MSI 450 MITX board and a Ryzen 3600 that is doing
| NAS/homeserver duty and it refused to POST without a GPU
| plugged in. Given its MITX and it only has a single slot
| needing it for PCI-E is a real pain, I intended to use it for
| SATA ports so it hurt my plans quite a bit.
|
| Its motherboard dependent but its definitely something to check
| with AMD Ryzen motherboards.
| dsr_ wrote:
| For years and years, many motherboards _did_ have graphics sets
| integrated in. These days, you 'll still see that on a lot of
| server-class motherboards.
|
| e.g.
| https://www.supermicro.com/en/products/motherboard/M11SDV-4C...
| -- the line about AST2500 BMC graphics? That runs a VGA port.
| btown wrote:
| I'm guessing the rationale for this is that even if the
| server's CPU can support onboard graphics, you wouldn't want
| to change the CPU's load profile just by plugging in a
| monitor to debug something? Or even to support CPUs that have
| no onboard graphics support?
| dsr_ wrote:
| Mostly the second -- the high end Intel and AMD CPUs don't
| have integrated graphics, and nobody wants to spend
| precious PCIe slots on a graphics card that won't be used
| except at install time and emergencies... or is more useful
| as a GPU slot that never produces video output.
| numpad0 wrote:
| That MacroSilicon MS2109 capture is super interesting! $11
| shipped for 1080p30 capture is unbeatable. I wonder what kind of
| host SBC is going to be necessary to build a clone BlackMagic
| ATEM Mini without choking up USB bandwidth.
| mmastrac wrote:
| A USB 2.0 device can use up to 480Mbps and MJPEG is on the
| order of 10s of Mbps (estimated), so I don't think you're
| anywhere near needing to worry about bandwidth.
|
| Your biggest complication will be real-time re-encoding and
| compositing with effects.
| numpad0 wrote:
| I can't believe it until I see it. I've seen USB EHCI choke
| up from just three webcams.
| mtlynch wrote:
| Ah! That's the name of it. Thanks! I didn't know how to tie it
| to any kind of identifier.
| devwastaken wrote:
| Are there any projects that can do similar but on a VPS? Used to
| be a group video service called rabb.it where you could get a
| streamed Ubuntu desktop for groups that you can control through
| the browser.
| tfolbrecht wrote:
| Check out Apache Guacamole! "clientless remote desktop gateway"
| basically VNC/RDP through a browser
|
| https://guacamole.apache.org/
| nanomonkey wrote:
| KVM = Keyboard, Video and Mouse
|
| For those, like me, who were ignorant of this particular use of
| KVM, and couldn't find it in the article or comments.
| superkuh wrote:
| The hardest part of this seems to be the V in the KVM and the
| solution of the author's is pretty neat. But I think things could
| still be improved by dropping his keyboard/mouse setup and just
| switching to the standard: barrier/synergy,
| https://github.com/debauchee/barrier
| jseutter wrote:
| While Barrier works well, TinyPilot is more capable. TinyPilot
| gives you full control of the remote machine, including BIOS
| screens. With Barrier you rely on having Barrier running on
| both machines, so you can't use it for things like reinstalling
| an operating system. Or fixing a machine that won't boot.
| mtlynch wrote:
| Thanks for reading!
|
| I'm not familiar with Barrier, but is my understanding correct
| that it requires software running on the target computer? If
| that's true, it wouldn't work for things like installing a new
| OS or managing BIOS because you'd have to wait for the computer
| to boot up fully before you're able to enter keyboard or mouse
| input.
| Neil44 wrote:
| I got a cheap Lantronix Spider KVM from eBay, it works quite
| well. Mine was an older VGA model but you can use it with a DP or
| HDMI to VGA adapter.
| somethingwitty1 wrote:
| Awesome! I could have built this with what I have at home, but I
| purchased because this is something worth supporting.
| mtlynch wrote:
| Thanks for reading and for purchasing!
| mudkip wrote:
| This is pretty cool (for managing servers cheaply), but I remain
| disappointed that remotely controlling computers over a network
| with low latency is still a difficult task. I've been trying to
| find a way to use a bunch of machines remotely over my LAN (for
| gaming / media playback on multiple devices), and have been
| somewhat disappointed at the quality / latency of the various
| options I've played around with. It's especially disappointing
| when you have 10gbps networking, and sending uncompressed 1080p60
| video over over the network with a couple ms of latency should be
| trivial, from a bandwidth perspective. Obviously this is a
| different problem than what you're trying to solve (remote
| management, so you have to do HDMI + USB stuff in hardware,
| adding some latency), but it's still annoying that there aren't
| great lower latency software options.
| xiao_haozi wrote:
| Steam link does it, and fast enough to play games with no
| noticeable latency.
|
| Not sure what the magic is, though.
| baq wrote:
| the latency is absolutely noticeable, the human brain adapts
| quite well though. i've switched mid-playthrough of ori and
| the blind forest (highly recommended btw) from a link to
| native 144hz and was blown away how easy the game has become
| :)
|
| the point still stands: most games are very playable via a
| steam link.
| mudkip wrote:
| I haven't tried Steam Link yet, but I might give it a shot. I
| was originally looking for purely remote desktop stuff for a
| combination of managing computers and gaming, so I was mostly
| testing stuff not specifically marketed to gamers. Ideally
| I'd also like something that does software<->hardware (at
| higher latency obviously), so I can stream older computers or
| game consoles to a variety of devices as well.
|
| I did end up trying Parsec, since I saw some people
| recommending it, and that was terrible. Latency was fine
| (~10ms software <-> software) and video quality was alright,
| but audio quality was terrible despite being set to the
| highest option - which is especially bad, because there's no
| option to send uncompressed audio, and whatever "optimization
| work" they were doing to reduce bandwidth made their entire
| product unusable, despite the fact that there's no need to
| try saving 1mbps over a wired LAN.
| fock wrote:
| the cool thing about this solution seems also, that it
| conveniently alleviates the "need a screen"-problem of the
| windows-screencapture-approach.
| mindslight wrote:
| SPICE (virt-viewer) performs well enough for my every day web
| browsing with VMs. The performance is annoying but adequate
| over wifi/WAN.
| mudkip wrote:
| I'm curious how well this works over a LAN - over a WAN, my
| expectations are way lower because of actual limitations from
| going over the internet, so I'm fine with some latency /
| quality loss.
| mindslight wrote:
| Sorry, I was trying to imply that it does work great over a
| wired LAN. I run my everyday browsers on a separate
| physical machine, communicating over gigabit ethernet.
| Videos with sound generally play fine, although I often
| youtube-dl longer ones for usability's sake. The main
| source of flakiness I've had is from opening too many tabs
| in low-memory VMs.
| SparkyMcUnicorn wrote:
| Have you tried out https://github.com/moonlight-
| stream/moonlight-qt ?
|
| If all your host machines are Windows 8+, then Parsec is
| fantastic and has clients for every major OS other than iOS.
| mudkip wrote:
| I looked into Moonlight, but don't have any nVidia cards
| laying around here to test with.
|
| I tried Parsec on one machine and was super disappointed.
| Video quality and latency were fine, but audio sounded like
| crap, despite streaming at 512kbps. Since there's no option
| to stream uncompressed audio, and no debug options to figure
| out why it sounded so terrible, I had to write off their
| entire product as unusable.
| ed25519FUUU wrote:
| Really neat project. Small optimization, you can use the RPI's
| gpu accelerated h264 decoding and free up a lot of CPU:
|
| Change: ffmpeg -vcodec libxh264
|
| To: ffmpeg -vcodec h264_mmal
| mtlynch wrote:
| Thanks, good tip! I ended up not using ffmpeg after I
| discovered uStreamer, but this is a good trick to have in my
| back pocket.
| fowl2 wrote:
| Interesting! I wonder if it'd be possible to skip the capture
| card and have the pi act as a USB graphics adaptor.
|
| Most firmware environments probably don't support them I guess.
| twicetwice wrote:
| There was another approach to the same problem posted on HN just
| yesterday[0], which took a very different route! Very interesting
| to compare/contrast the two appraches. That one doesn't do video,
| just gets you a terminal. (Not sure if it would let you mess with
| the BIOS or install a new OS like this one does? Not familiar
| enough with serial ports to assess.)
|
| But anyway, TinyPilot is super cool! I'd love to get it set up
| one day. And the "life story" as to how it came to be was really
| neat, and made me feel like I understood the whole solution.
| Great article!
|
| [0] https://news.ycombinator.com/item?id=23915777
| vidanay wrote:
| I'm all in favor of cool projects, and I have done my fair share
| of useless experiments. But wouldn't it just be simpler to attach
| a dumpster-sourced monitor and keyboard to the server in question
| for the 3-4 times a year you brick it? To me the idea of a
| locally placed 1:1 KVM "switch" (huh? it's not switching anything
| if it's 1:1) is crazy. It makes sense if it is remotely located,
| but not if it's within your own home.
| CyberDildonics wrote:
| Remote monitors like this are occasionally used in offices so
| that powerful workstations can be put in racks. I'm not
| completely convinced it is a great idea, even for that
| application, but it does get used in those instances quite a
| bit.
| toomuchtodo wrote:
| Makes sense if you want the flexibility to do it from anywhere
| over IP, even across the house.
| cm2187 wrote:
| Every time I update windows and reboot, I never know if the
| server is bricked or if it is just windows taking ages to
| update.
|
| Also if you use TPM / full disk encryption for a server in
| colocation, it only takes a firmware update for TPM to request
| to reenter the key on reboot.
| mtlynch wrote:
| Thanks for reading!
|
| > _But wouldn 't it just be simpler to attach a dumpster-
| sourced monitor and keyboard to the server in question for the
| 3-4 times a year you brick it?_
|
| Maybe it's just personal preference, but I'd much rather plug
| in a Raspberry Pi than a whole monitor and keyboard. My server
| is tucked away in the corner without a good desk surface to
| place a keyboard and monitor.
|
| With the Pi, I can just plug it and go back to my desk and do
| everything through the browser. It's also nice for when I have
| to Google things about why it's not booting, I can just do it
| from another browser tab rather than physically walking back
| and forth between computers.
| detaro wrote:
| not sure why you talk about "switch"? The word never appears in
| the article?
|
| And at such a no-brainer price (especially if you already have
| a Pi), kind of worth it just to avoid the hassle of moving a
| screen around.
| vidanay wrote:
| https://mtlynch.io/tinypilot/raritan-kvm.png
| mtlynch wrote:
| I think the confusion is that the original comment was
| worded as if _I_ called TinyPilot a switch, but I think you
| 're actually saying you think it's strange that Raritan
| calls _their_ device a switch, despite the fact that it 's
| only 1-port.
| dewey wrote:
| Of course it would be simpler, but it's also addressed multiple
| times in the blog post why he decided to do it anyway.
|
| I'm glad he did because it looks like a fantastic project.
| Naac wrote:
| This is a great writeup.
|
| I wonder if this can be extended to connect multiple servers to a
| single Pi.
| EvanAnderson wrote:
| This looks great. To be useful in the datacenter environments I
| work in such a device would need VGA capture, though. Most
| servers don't have HDMI ports in my experience.
|
| Anybody know of a good, cheap V4L2 USB-based VGA capture dongle?
| louwrentius wrote:
| Most servers have built-in IPMI.
| diabeetusman wrote:
| Could always add another dongle with something like this:
| https://www.amazon.com/dp/B07BKYBKGP maybe?
| bserge wrote:
| Most obvious choice, but the USB port might not be able to
| provide enough power. You could splice in an external adapter
| with a bit of work, though :)
| Nexxxeh wrote:
| I've used one of these a couple of time and they work great,
| not yet hooked up into the HDMI cap device but can test if
| anyone is interested.
| Nextgrid wrote:
| Not sure if they are still easily available but look into
| https://blog.benjojo.co.uk/post/userspace-usb-drivers.
| crypt1d wrote:
| KVMs have been a the bane of my existence over the last 10 years.
| Almost 99% of the time they come with some ancient Java
| dependency that breaks on any modern OS and is barely usable. Not
| to mention the nightmare-ish KVM experience big players like OVH
| and Hetzner provide.
|
| This is a superior solution to all of them.
| louwrentius wrote:
| No. Modern IPMI is HTML5 based. Lightyears better than the old
| java/.net clients or this (awesome) hobby project.
| Severian wrote:
| You could also probably add power/reset functionality by hacking
| something like this:
|
| https://www.amazon.com/SilverStone-Technology-Wireless-Compu...
|
| Or possibly just wiring up a transistor to the power button pin
| (not sure if it sources or sinks) between motherboard and the Pi,
| and just hold it high until it boots.
| fuzzy2 wrote:
| Very nice. I've been looking into the same thing, with a
| different video grabbing method though: A HDMI-to-CSI bridge
| (Auvidea B101/B102). Hopefully, this could somehow work with a
| Raspberry Pi Zero W, which is very compact and also supports USB-
| OTG. Unlike the Raspberry Pi 4, a single USB port can easily
| power it.
|
| Unfortunately, the much more powerful B102 bridge isn't
| available. :(
| bronco21016 wrote:
| Because of COVID my work on the road has come to a screeching
| halt. I was always using my iPad with an external keyboard for
| nearly everything and became really accustomed to having iMessage
| always a key command away.
|
| Now I work at home at a desktop with Ubuntu. It's a huge
| disruption to use iMessage now as I have to switch
| devices/keyboards.
|
| I had the thought of doing almost exactly this with the
| Ligthning-> HDMI adapter and some form of Bluetooth keyboard
| emulation. I can't wait to build one of these and start
| experimenting.
| rjeli wrote:
| oh, i wrote software that does this over airplay wifi mirroring
| and a bluetooth dongle as a mouse. i gave up because I couldn't
| convince my phone to take a tablet hid profile for seamless
| mouse capture. it's messy but I'll throw it on github in a bit
| annoyingnoob wrote:
| A cool solution to a common problem.
| bserge wrote:
| This is some great timing, I might need a KVMoIP setup soon and I
| couldn't find anything cheap. Very nicely written article,
| thanks!
| mtlynch wrote:
| Awesome, glad it was helpful! Thanks for reading.
| mtlynch wrote:
| Author here. Happy to answer any questions or take any feedback
| about this post.
| simlevesque wrote:
| How would you remotely connect to something like this ? using
| something like ngrok ?
| mtlynch wrote:
| Yeah, I haven't looked into that much because everything is
| on my local network. ngrok looks like it would work. One of
| my users is looking into remote.it, which seems like a
| similar service.
| gyrgtyn wrote:
| zerotier
| jimatremoteit wrote:
| I work for remote.it. If you or your users need any help
| setting up remote access to the TinyPilot let us know. This
| looks like a great application. We can make ssh/VNC/http on
| the Pi available remotely over internet as a free service
| no problem.
| mtlynch wrote:
| Oh, that's awesome. Thank you!
| fock wrote:
| or VPN on your router? or just get a VPS and run wireguard.
| ghaberek wrote:
| Would a Pi Zero W work for this, or do you need a full-size Pi
| 4? I would think that with the HDMI dongle doing the hardware
| MJPEG encoding, a Pi Zero might suffice. It'd be really neat to
| A) bring the cost down another $30 and B) be able to package
| everything into a tiny 3D printed case.
| Nexxxeh wrote:
| The immediate issue would be the Pi Zero W only has one
| usable (micro)USB port, the other port is Power In only. If
| you run it for OTG, you can't use it for the dongle.
|
| There would be ways around this though, perhaps using a cheap
| microcontroller for the USB HID stuff.
| ghaberek wrote:
| Yeah I forgot that only one of the USB ports actually does
| data. I guess you could use a Teensy that interfaces
| through the GPIO pins and pretends to be the keyboard and
| mouse.
| Nexxxeh wrote:
| That's what I'm thinking, or worst case, one that
| communicated via USB to TTL adaptors. Or an ESP-based
| board that connects over WiFi. Or BT-enabled board.
|
| Combined with a HDMI switch, you could then control
| multiple devices with just one Pi+Cap device.
|
| I've been looking to do something similar for a while,
| albeit possibly with Windows as that's where I've (very
| rusty Delphi) programming experience.
| mtlynch wrote:
| Thanks for reading!
|
| > _Would a Pi Zero W work for this, or do you need a full-
| size Pi 4?_
|
| I tested Key Mime Pi (the keyboard-only version) on the Pi
| Zero W and it worked great. I haven't tested TinyPilot on the
| Pi Zero W, but I _think_ it will work. The video encoding is
| happening in the HDMI dongle, so it doesn 't hammer resources
| much. I don't have a USB to microUSB adaptor on hand, but
| I'll order one now and see if it works.
|
| > _be able to package everything into a tiny 3D printed
| case._
|
| Yeah, that would be neat! One of the biggest issues I have
| with TinyPilot's setup right now is that it looks kind of
| like a bunch of random hobbyist parts stuck together. A 3D
| printed case would be good and wouldn't have the heat issues
| that Pi 4 has.[0]
|
| [0] https://www.jeffgeerling.com/blog/2019/best-way-keep-
| your-co...
| cricalix wrote:
| You might also be able to use the "standard" radio kit
| metal boxes - tap some standoffs, carefully drill some
| holes for wires etc. Dunno which works out better for the
| world - ordering a pre-fab metal box that you have to do
| some work on (or perhaps use
| https://www.frontpanelexpress.com/ to get a customised
| enclosure), or printing something from plastic. Might
| depend on production volume, metal used etc.
| trm42 wrote:
| Do you happen to have any idea, whether older RPIs like 1
| or 2 could work for this fast enough? Have some of those
| laying around.
| mtlynch wrote:
| The video capture part should work, but I don't believe
| they support USB OTG, so they wouldn't be able to
| impersonate the keyboard.
|
| The official documentation[0] says all Pi devices have
| USB OTG, but I'm not sure if there's something else about
| the Pi 4 and Pi Zero W that allows USB gadget mode
| because I've never found anyone talking about using it
| before recent generations of Pi. This StackExchange
| answer says the A and the A+ had it, but that the 2
| doesn't.[1]
|
| [0] https://www.raspberrypi.org/documentation/hardware/ra
| spberry... [1] https://raspberrypi.stackexchange.com/ques
| tions/71613/how-to...
| Scaevolus wrote:
| I'd expect the Pi Zero W to be fast enough to pass
| through the MJPEG stream and impersonate the keyboard,
| which should cut the cost by $20+ plus however much you
| save on not needing a fancy case.
| [deleted]
| mtlynch wrote:
| Yeah that's true. I stopped thinking about the Pi Zero W
| early in the project because I assumed it would choke on
| video encoding. When I discovered that the HDMI dongle
| was doing the heavy lifting, I forgot to revisit that
| assumption. I'm going to order an USB to micro-USB
| adaptor to test it out because it would slim things down
| significantly.
| Deathmax wrote:
| I think you might run into a lack of connectivity on the Pi
| Zero W. Since the only data USB port has to run in device
| mode, I would assume you can't connect the HDMI capture
| device.
| wojciii wrote:
| Cool project, but what about power management? What happens if
| the PC being controlled crashes and does not let you reboot it
| using keyboard shortcut?
|
| I'm might be damaged by testing and working with embedded
| development.
| zyx321 wrote:
| If you need access to the power and reset, you can replace
| the respective buttons with a cheap relay switch controlled
| by GPIO. If you know what you're doing you can also solder
| your own circuit using opto-isolators instead of relays, to
| reduce the power draw on the Pi.
| hedora wrote:
| This isn't a bad choice:
|
| https://wiki.52pi.com/index.php/DockerPi_4_Channel_Relay_SK
| U...
|
| It's $17 for four relays, expandable to 16. If you wire it
| "normal closed" then the relays will only draw power while
| it's resetting the other machine.
|
| However, the relays are only rated for 3 amps. (360W at
| 120V). Also, the board is labeled backwards so, the NO port
| is normal closed, and NC is normal open.
|
| Has anyone found something that's similarly plug and play
| with a higher amperage rating?
|
| Edit: this would work as a switched AC outlet (to replace a
| four outlet PDU) or for hot wiring the power / reset
| buttons. You could do both buttons and the AC line and have
| a relay left over.
|
| I'd feel funny running AC that close to the lower button
| wires though (if cross those wires, it will certainly let
| the magic smoke out of your motherboard).
| fanatic2pope wrote:
| Plug it into a smart outlet running tasmota.
| mtlynch wrote:
| Thanks for reading!
|
| > _Cool project, but what about power management? What
| happens if the PC being controlled crashes and does not let
| you reboot it using keyboard shortcut?_
|
| Yeah, that's one of the limitations. TinyPilot can't control
| power for the target computer.
|
| I don't know of any way to manage power without connecting
| the Pi to the target machine's motherboard, but that
| increases complexity significantly. I'm using this for a
| homelab, so it's easy for me to walk over and cycle power if
| that ever comes up, but for this to support more remote
| scenarios, I'd need to address this.
| baq wrote:
| hook up a gpio pin to a reset switch jumper somehow?
| davidzweig wrote:
| Wake-on-Lan can handle powering on. It should be possible
| to directly connect a RPi GPIO pin directly to the 0.1"
| headers on the motherboard.. the power and reset buttons
| are just closing a circuit to pull high/pull low an input
| pin. Use a 1k resistor between the Rpi and motherboard
| headers for protection.
| oakwhiz wrote:
| Perhaps a fake USB device that issues power or sleep button
| requests could work. I had limited success with this on
| Linux using an HID keyboard emulator. However this won't
| work on a machine that's too far gone to respond to USB,
| and that's also an issue with the physical power button as
| well. Perhaps an AC latching relay would work to cut power.
| wojciii wrote:
| APC produces (or rebranded) power control modules you can
| control over Ethernet. They are probably expensive.
|
| There are most likely cheaper products which would work.
| You should probably implement some kind of power control
| interface that could be used. Calling a shell script would
| be enough and some example implementations provided by your
| users. :) It doesn't need to be complicated.
| Nexxxeh wrote:
| A horrible way would be to set the target to power on after
| power loss. Plug the target into a WiFi-controlled smart
| plug, like the Belkin Wemo. In the event of catastrophic
| hard lock, power cycle it at the wall.
|
| A better way would be a relay and microcontroller, which
| you could also potentially use for the USB HID stuff too.
|
| In theory, you could have a HDMI switch, a single Pi and
| HDMI grabber, and just a microcontroller board for each
| target machine that could have power button control,
| keyboard emulation etc built in.
| FatalException wrote:
| If the motherboard of the PC being controlled supports Wake-
| on-Lan that may be a viable option to send a packet from the
| local subnet to boot up the computer.
| https://en.wikipedia.org/wiki/Wake-on-LAN
| swsieber wrote:
| If you can plug stuff into it, just use the KVM from a laptop
| and sit by it.
| tootie wrote:
| If this just requires USB and HDMI, it should theoretically
| work identically a for Mac Mini or even something like a Fire
| TV, yes? Is there an upper limit on resolution and frame rate
| for the dongle?
| mtlynch wrote:
| > _If this just requires USB and HDMI, it should
| theoretically work identically a for Mac Mini or even
| something like a Fire TV, yes?_
|
| I believe so, but with the caveat that I haven't tested it.
| Does Fire TV take USB keyboard input?
|
| I have successfully captured video from a Roku Premiere[0],
| even though it's HDCP protected. The LKV373A couldn't capture
| anything out of it, but the $11 dongle did just fine. But
| that was just video capture. I didn't have a way of sending
| input to the Roku.
|
| > _Is there an upper limit on resolution and frame rate for
| the dongle?_
|
| Yes, the limit is 1280x720px @ 30FPS.
|
| [0]
| https://twitter.com/tinypilotkvm/status/1277994838210875392
| Uhhrrr wrote:
| I love how this is a project which puts together several
| different projects which are themselves the product of
| significant amounts of effort: RPi, the HDMI-USB dongle, the
| browser, and uStreamer. I think we are in for an interesting
| decade or so of people plugging things together like this.
|
| I'm curious why you use the browser instead of ffplay for
| decoding and display. I'd guess ffplay would be faster - but
| maybe not?
| mixmastamyk wrote:
| For one, it wraps the screen and input into one window. Using
| two would be unwieldy.
| fock wrote:
| and today I was wondering how to solve the video problem!
| that's great timing.
| tlamponi wrote:
| Really nice, exactly what I need just now as I'm setting up a
| remote workstation/part-time server at my families farm, but
| did not have a motherboard with IPMI/iKVM at hand.
|
| Oh, and thanks for using Proxmox VE! Was positively surprised
| when I saw our installer flash up out of nowhere :)
| mtlynch wrote:
| Wow, thank YOU for making Proxmox! I'm switching over after
| three years of Kimchi[0], and Proxmox does everything so much
| better.
|
| [0] https://github.com/kimchi-project/kimchi
| silverp1 wrote:
| Any thoughts on how this could work with VGA for example?
| mtlynch wrote:
| I believe it should work with a VGA to HDMI adaptor, as
| another commenter suggested[0], though I haven't tested this
| personally.
|
| [0] https://news.ycombinator.com/item?id=23928401
| da39a3ee wrote:
| This isn't an area I know anything about but I really enjoyed
| your write-up (I still don't know what KVM stands for! But I
| get that you wanted to act as a physical keyboard and display
| over IP). From a quick skim of your site it looks like you've
| worked at large companies and now are doing some independent
| projects. Do you think you'll go back to working for a company
| (perhaps a smaller one?), or do you see yourself working
| independently for many years? I ask because (a) I'm also
| casting about at a similar point in my career doing independent
| projects, but (b) I've never worked at a truly large company,
| and (c) (someone like) you seem(s) like you'd be a great
| colleague to work with, and (d) my vague ambition is to work
| for a small company with skilled colleagues that I can learn
| from and to work on "technical" projects as opposed to product
| development but (e) I guess, when I see talented people such as
| yourself apparently rejecting the conventional job market, I
| partly infer that they've looked at what's on offer and
| declined and thus that I'm deluding myself in thinking that
| I'll find something in the conventional job market that I
| really want.
| mtlynch wrote:
| Thanks for reading!
|
| > _I still don 't know what KVM stands for!_
|
| Oh, keyboard, video, mouse. The article does define it, but
| it's a little buried.
|
| > _From a quick skim of your site it looks like you 've
| worked at large companies and now are doing some independent
| projects. Do you think you'll go back to working for a
| company (perhaps a smaller one?), or do you see yourself
| working independently for many years?_
|
| I'd love to continue working for myself forever. My ideal
| would be if I could find a business sustainable enough that I
| can hire 2-5 developers and other teammates to work with me.
| If I did have to go back to being an employee, I'd probably
| lean toward something smaller.
|
| It's very much about your temperament, what type of work you
| enjoy, and how much you value flexibility and autonomy. A
| good way to test the waters is by building a side business
| and see if you enjoy it more than your job. You can also
| read/hear more about the lifestyle in places like Indie
| Hackers[0], Starter Story[1], and WIP[2].
|
| But I agree with you that you pass up certain kinds of growth
| by working on your own. I'm happy that I had ~10 years of
| experience with big companies before doing my own thing. I
| learn a lot on my own, but I don't think I could have learned
| a lot of my software "craftsmanship" kind of skills (e.g.,
| designing for maintainability, creating repeatable, well-
| documented processes) had I not worked for Google and
| Microsoft.
|
| [0] https://indiehackers.com
|
| [1] https://starterstory.com
|
| [2] https://wip.chat
| PaulKeeble wrote:
| Have you looked at a solution for controlling the power on/off
| yet? This was something I was considering to do with a
| Raspberry PI and a relay and I figure it is the final part of
| the solution for when the machine inevitably crashes.
| Admittedly if its just across the room it was less of a concern
| but I have had the need to restart while I was away before and
| it would be nice to be part of the solution.
| MayeulC wrote:
| This is a pretty simple thing to achieve electrically, just
| plug something instead of the power button inside the
| computer. You likely just need one mosfet. If soldering is
| too uncomfortable, you can find relays to control the main
| power supply (requires screwing a power supply cable and a
| couple dupont connectors).
|
| If you don't want to touch anything related to electronics,
| you could rely on enabling a watchdog on boot-up. Or control
| if from a smart power supply (you likely have a UPS plugged
| in, for instance). Use the power after power loss BIOS
| feature, or WoL to wake it up.
| pdevine wrote:
| Dude, thanks so much for this. I have a loud machine I'm using
| for ML stuff and I've been reluctant to move it to the basement
| as I didn't want to have to run downstairs with a monitor for
| the odd issue. I also looked at KVMs and was annoyed at the
| prices. I have a R Pi sitting here I was looking to do a
| project with. This is perfect!
| mtlynch wrote:
| Oh, that's great! So glad it was helpful!
| tinco wrote:
| This is epic, I run a small computer cluster using workstation
| hardware (AMD 3970X's) and no IPMI boards exist. If I get some
| time I might build 7 of your little system to manage them all.
| Thanks!
| mtlynch wrote:
| Awesome! I'd love to hear how it turns out.
| C1sc0cat wrote:
| Oh nice I will have to look into this as I was considering Using
| a dual pc set up for streaming and this would be great for
| controlling the second pc (mac mini)
|
| I want to have main pc for running ROLLd20 and a daw - then use a
| mac mini to run the processed audio from my DAW into hangouts.
|
| This is so I can properly play in audio and , music cues as well
| as altering my voice to suit the character eg a galdos style for
| a robot
| lukevp wrote:
| You could probably do this with the loopback features of a
| podcast style interface and not need a second computer. The one
| I use is the MOTU M4, the M2 is a little cheaper.
|
| https://m.youtube.com/watch?v=IKjKymjc_R8
| C1sc0cat wrote:
| Yes I have looked at virtual loop back like Voicemeeter and
| might be able to do it with the routing aspects of the
| focusrite software.
|
| It is of course the sort of thing that should be baked into
| the OS.
| mtlynch wrote:
| Thanks for reading!
|
| I'm not an audio guy, so I can't comment on how well it would
| suit that scenario, but it sounds like a neat pipeline, and I'd
| love to hear about it if you end up building it.
| C1sc0cat wrote:
| I was more a better way of remote controlling the mac vnc
| works but its a bit crap.
|
| The main idea was for GM's to use mood music to set the tone
| or for audio effects the classic red alert should for a sf
| based game.
|
| What I wanted it for was real time voice changing for
| character voices - basically the flanged goa'uld or the
| glados formant shifting robot voice or the classic Dalek
| voice
| babuloseo wrote:
| great blog post! will try to watch the video at some point.
| NietTim wrote:
| Great little project! I had no idea capture cards got that cheap
| mtlynch wrote:
| Thanks for reading! Yeah, my understanding is that these
| capture cards are fairly recent. I think my timing was pretty
| lucky because a lot of earlier projects had to do HDMI->S-Video
| and S-Video->USB[0] to keep costs down because there weren't
| any inexpensive HDMI->USB options at the time.
|
| [0] https://github.com/Fmstrat/diy-ipmi#setting-up-the-hardware
| jwatzman wrote:
| If you're looking to buy the card in the article, I just got
| one of these https://www.aliexpress.com/item/4000958505670.html
| which looks to be exactly the same card, and doesn't require
| scouring eBay. I haven't done much with it yet, but can confirm
| that it arrived to me in the UK with no issues, and seems to
| work from a quick test.
| fulafel wrote:
| A major con of the enterprisey ilom systems (such as the idrac)
| is their atrocious security track record. You are basically
| giving up your "the network is untrusted, I can survive its
| compromise" badge if you plug in one of those.
| parliament32 wrote:
| Well those ports should never face the internet anyway. Most
| servers will have a dedicated (physical) port you use for IPMI
| or whatever -- vlan that and only allow access from your VPN.
| If you're extra secure you can full on disable the switchport
| until you need it.
| fulafel wrote:
| This fail-open "should" is bad besides for the obvious
| reasons, also because it'll be extra ops complexity compared
| to a secure kvm widget that you don't have to handle with kid
| gloves.
|
| (And thirdly because of the sibling comment noted footgun..
| or silent foot-boobytrap more properly)
| parliament32 wrote:
| The problem is BMC has an astounding array of features[1]
| that are worth the operational complexity. This isn't just
| KVM like in OP's post... being able to remote mount images
| is a godsend when you're provisioning a server or
| diagnosing hardware issues or doing a BIOS update on the
| other side of the globe (with your other alternative being
| shipping a flash drive[2], then paying $200/hr for DC
| remote hands to plug it in for you).
|
| [1] https://www.supermicro.com/en/solutions/management-
| software/...
|
| [2] don't even try to talk about PXE booting if you've
| never tried to get DHCP+BOOTP to work over a WAN
| extrapickles wrote:
| Make sure in the BIOS to disable fallback to one of the other
| ethernet ports. Quite a few IPMIs will listen on eth0 if it
| looses the dedicated IPMI port link by default.
| iron2disulfide wrote:
| This is cool. Any chance this would scale for many machines? I
| have a ~15 machine lab with no KVM setup right now, and could
| really use something like this if it works for a large number of
| devices.
| mtlynch wrote:
| Thanks for reading!
|
| I don't think there's a way to get the Pi to capture video or
| impersonate keyboards for more than one computer at a time.
|
| A neat idea a friend proposed to me was to buy a "dumb" KVM
| that supports switching through keyboard hotkeys and use that
| to scale it to multiple machines. See my comment here:
| https://news.ycombinator.com/item?id=23928251
| jolmg wrote:
| I'm not really into electronics, but I imagine it wouldn't be
| that difficult to control the switch of a cheap KVM-switch with
| the GPIO pins of the RPi. One might even control multiple KVM-
| switches and daisy-chain them.
| iron2disulfide wrote:
| Haha, I am kind of the opposite: I work on electronics, and
| am not much of a sys admin. One of the problems I've run into
| is that I haven't found a single switch solution with enough
| connections. I _could_ build a multi-level multiplexer with
| many switches, but that 's too much effort. If TinyPilot can
| support multiple KVM-over-IP connections, it would be a
| perfect fit for me.
| jolmg wrote:
| > If TinyPilot can support multiple KVM-over-IP
| connections, it would be a perfect fit for me.
|
| RPis only have 1 OTG port, though. A device that could get
| it to handle more machines with that single port would
| functionally be a KVM-switch. I don't think there's a way
| around that.
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