3.5 Virtual Machine, Network, Hard Disk Creation Part 5
5 hours 8 minutes
carrying on synthetic versus emulated network adapters,
emulated what simulated
this is It's basically it's a software component that implements
least common denominator set of instructions
on the universal toe. All devices of that time,
also, judge s. So you could have two virtual switches in this scenario if needed. Absolutely. You could
if they were external, you wouldn't be able to cook both of them into the same physical adapter
because of just the way they connect up. You can share them if you could have to adapt is connecting into a virtual switch. But if you connect them both to, like, say, there's one adapter nya to external networks,
things going to stop going a bit haywire on the network. So
you can, in some scenarios, but not necessarily a ll the time it would depend
because of the flexibility. Let me just roll this back a little bit because of the flexibility off
the way virtual switches work.
There are ways where you can it will allow you to build a network,
but it won't necessarily work because what you're asking it to build is perfectly logical. But when you then start connecting wires together. It's almost like if you had to physical switches and you thought you know what? I'm gonna plug this switch into this switch. Now, that's a perfectly normal thing to do. Connect two switches together,
but I'm gonna say right. Well, this the other end of this switch on the uplink. I'm gonna connect this switch back to that switch. You're gonna create a loop.
Now, you can certainly do that.
But why would you want to? Do you see what I mean? You would just use that one link,
so it allows a lot of flexibility. But you can also be too flexible and create scenarios where you don't want situations to occur as well. So it's just a case of being aware of those Basically,
yes. So synthetic roses emulated network adapters. So, um,
what it does so, as I said, this uses the least common denominator set of instructions like the way it gives date around talks to things,
This guarantees are pretty much going to all but guarantees that it will be usable by almost any operating system. Even those that hyper V doesn't directly support
s. So that's that's the benefit of happening
a emulated network adapter. Now these devices can be seen even in a minimalist pre boot execution environment. Now
those of you who might have heard of pre brew execution will know it is pixie
on. This is why you would use an emulated network adapter if you want to do things like build machines were using a Windows deployment server or something along those lines.
Um, so Daniel has asked, How can you connect a virtual switch to a physical Nick?
as I said so what you would do is you would have the physical nick in the host, and that's literally what an external
switches external virtual switch. It allows that virtual switch to pick up a physical network
on connect to the hardware and use it. That's literally an external network. So you would use an external network to connect to a physical nick
effectively so spanning tree protocol that Eddie said, is a little bit more than what we might discuss in the foundation course
you're on the right lines. They're ready, of course, and it is clear that you've you've done this before, so it's good. But yes, that you would use an external network in this environment to actually
connected to the physical nick, and then it would be able to access the rest of the network effectively.
So going back to this simulated so drawback to this the drawbacks of simulated network conductor. The software component is a complete representation of a hardware device,
which means that includes the need for things like I are cues and interrupt request
on a memory input output operation
now within the virtual machine.
All the translation occurs in the virtual CPU,
and once the virtual CPU has converted the V EMS communication
into that meant for the device, it's passed over to the construct that Hyper V has,
and Hyper V then performs the same exact function to interact with the real hardware.
All of this happens in reverse as the device sends data back to the drivers and applications within the virtual machine.
So it means that there's a lot of resource usage to send data backwards and forwards through an emulated network adapter.
So, yeah, it's massively expensive for computation, which means it's going to slow down that GM on you. You can very quickly notice these types of things when you boot a generation one versus a generation to machine, we discuss these. In previous episodes, Jen one tends to have emulated. Gentoo tends to have synthetic.
Andi would use one over the other in certain situations.
But it is, as I mentioned, a complete representation of the hardware.
and it needs its own basic i R Q and memory. I owe operations,
and this is basically how it would lay out if you saw it in an environment. So it's
you got the virtual machine at the bottom,
passing data backwards and forwards between hyper V that then speaks to the driver. The driver speaks to what's called the hardware obstruction layer
on. Then that goes through to the CPU.
The CPU deals with the memory passing stuff in and out on. Then that goes over to the device, and that device sends out to the network. And then you have the entire reverse process coming all the way back in, which could be
really tedious and massively memory intensive and computational. E really expensive to do.
Tom asks. Can you go over fail over networking? We go over it a little bit. Tom. It's a little more than what we would deal with in a fundamentals course. This'd is very much a case of going over kind of the basics to understand virtualization. If you've been with us from the beginning,
then we've covered multiple six segments in areas.
But there is a little touches on it throughout the course. But going into it, I mean, I could I could make a series on its own about fail over networking.
It would take up that much time. So I do apologize. Hopefully, in the future course we can cover a bit more. I have been asked to attend to other courses in the future where I'm going into more detail on this, including things like Windows Server, which would have fail over built into it and that kind of things. They're clustering, networking like that as well.
But for the moment, we need to focus on the fundamental side of it.
I do apologize, Tom, but
I would love to in the future. Definitely
Synthetic, so synthetic hardware is different from emulate. Hardware in the hyper V does not create a software construct to masquerade as a physical device
now, instead, it uses a similar technique to the Windows Hardware Obstruction Layover. How
on presents interface that functions more closely to the driver model. The guests still needs to send instructions through its virtual CPU, but it it's able to use the driver model to pass these communications directly into the hyper V through the what's called the V M bus on the V M bus driver.
And the drivers that dependent on it
need to be loaded in order for the guest to be able to use that synthetic hardware at all.
the drawbacks of it s So this is why synthetic and scuzzy devices, which is just an interface for attaching devices, cannot be used prior to window start up. So
if you do that, if you have a synthetic network adapter, you're not gonna be able to do things like pixie, which is the pre boom execute environment
s so you can't do when those deployments service's or anything along those lines where you're pushing out images of machines to the network and saying, Please install this for me that won't work with a synthetic. You need to emulate it on that
And so yet no pixie and This is kind of how it would look over all s o. The virtual machine has an app working with a driver which passes up to hyper V and then moves across and basically allows it to be a lot less
interfaces directly with the driver rather than needing the VM to do everything. So the APC unjust? Go, guys, I've got this information. I need to get it out. The driver goes yet I'm here, Potter over. I'll deal with Robert and in the virtual machine just carries on doing what it needs to do. This means that it's doing a lot less work,
which means that the virtual machine doesn't end up being
computational. E really resource intensive.
If you do run Jen one versus Jen to machines side by side. Jen one uses emulated Gentoo uses synthetic
and you can really tell the difference, like booting them up. If you hit, start both of them at same time. The speed difference is phenomenal. The only difference being is that emulated is the only one that can do environments on a network where it's before the operating system is loaded.
carrying on from there