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Re: [tlug] [tlug-admin] Call for presenters 14th Nov

On 2020-11-06 13:02 +0900 (Fri), Edward Middleton wrote:

> On 5/11/20 11:43 am, Christian Horn wrote:
> > On Wed, Nov 04, 2020 at 01:01:08PM +0100, Christian Horn wrote:
> > - building KVM devices with HDMI grabbers and raspi: connect a
> >    system via HDMI and usb to the raspi, and the raspi can not
> >    only grab HDMI but also emulate usb mouse/keyboard to that
> >    connected system
> If you could combine it with power control functionality it could make a
> pretty cool DIY iLO[1] alternative.  Though it looks like you can do most of
> that with Intel Management Engine[2].

I've had extensive experience with LOM back in the late '90s and 2000s, and
again back around 2016 (when I discovered that kids these days had no clue
and were buying ¥1500 Ethernet KVMs for systems that already had full

Generally, if you're using Linux (or any other Unix) and using keyboard and
video for LOM you've made a wrong turn; serial consoles are simpler,
require much less software, usually reduce memory usage on the host, and
let you log all the console output.

Any even half-way decent rack mount server will have its own management
module (typically a small independent Linux-based machine called a BMC or
Baseband Management Controller) conected to one of the Ethernet ports and
supporting a command-line interface and IPMI. This will let you power cycle
the machine, reboot it, and hopefully let you set up boot devices so you
can do a remote install without ever having to touch the machine yourself.
(You just have the machine shipped to the data centre, pay the guys there
to plug it in, and do everything yourself after that.) In 2016 I was using
IBM and Supermicro servers, both of which support this.

You'll also usually be needing to configure a switch; buying a managed
switch (Netgear makes plenty under ¥10,000, even some small ones as cheap
as ¥3600[1] which are useful for learning on and testing configurations)
lets you reconfigure your rack in arbitrary ways without having to ask the
data centre folks to recable things. This is important in part because you
always want your management interfaces on a separate network; they are
generally not terribly secure and must be firewalled.


There are more details, of course, but this should give the general sense
of how you should be setting things up. Of course, these days it makes more
sense just to go with cloud VPSs, unless you're in a situation where
regulatory or similar reasons prevent that. (In my case, in 2016 we were
doing financial transactions where records had to be kept on hardware
physically in the country in which the transaction occurred.)

> I was interested in using it as a transparent pass-through device so you
> could plug it between the presenters laptop and projector and use that as a
> source for OBS[3], so you could combine video of the presenter and slides.

I've been interested in that sort of thing too, though in my case in order
to bring a display capture of a retrocomputer (e.g., a Commdore 64) into a
videoconference. But the issue with doing it through OBS is that you end up
with a single channel connection to the conference with central control of
what appears on it, rather than letting participants decide which stream
(presenter, slides, video output) they want to see in large form, which I
think would be nicer. Unfortunately, I've not seen any easy way to have a
single machine with multiple video inputs each separately sending to the
conference, so to date I've done this by setting up a separate laptop doing
video capture for each stream, which is obviously a bit annoying.

Curt J. Sampson      <>      +81 90 7737 2974

To iterate is human, to recurse divine.
    - L Peter Deutsch

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