WEBVTT 1 00:00.000 --> 00:05.040 So we've mentioned the concept of virtual machines or VMs, but what exactly are 2 00:05.040 --> 00:11.480 these? Well, when we're thinking about it, this is simply a set of software and 3 00:11.480 --> 00:17.040 it's a presentation of resources to the application that we're installing, 4 00:17.040 --> 00:22.240 meaning that it's going to appear to have CPU, it's going to appear to have 5 00:22.240 --> 00:26.040 memory and all of these other hardware components that we've talked about 6 00:26.040 --> 00:32.100 belonging to a PC or a server. Now this is meant to simulate again having WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 6 00:26.040 --> 00:32.100 belonging to a PC or a server. Now this is meant to simulate again having 7 00:32.100 --> 00:37.800 physical server resources. So I install an application onto this operating 8 00:37.800 --> 00:38.160 system, 9 00:38.160 --> 00:43.680 but it's all part of a virtual machine that once again is in software. So this 10 00:43.680 --> 00:48.000 operating system that we're installing onto the virtual machine, again, it 11 00:48.000 --> 00:48.200 needs 12 00:48.200 --> 00:53.580 to think that it has access to all of these different resources. And so when we 13 00:53.580 --> 00:57.300 see what's actually happening here, part of the responsibility of the 14 00:57.300 --> 01:02.280 hypervisor is to take a portion of the real amount of let's just say memory WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 14 00:57.300 --> 01:02.280 hypervisor is to take a portion of the real amount of let's just say memory 15 01:02.280 --> 01:08.280 here and carve some amount of it up and deliver it to this virtual machine. But 16 01:08.280 --> 01:11.760 then we've got another virtual machine over here with an operating system and 17 01:11.760 --> 01:15.240 an application. And so we're going to need to carve some amount of it and 18 01:15.240 --> 01:15.840 deliver 19 01:15.840 --> 01:20.840 it over here as well. But this is why we can actually improve the efficiency of 20 01:20.840 --> 01:26.300 our overall network and virtual space because remember what we said was one of 21 01:26.300 --> 01:29.620 the problems of the bare metal environment. And that was that if this 22 01:29.620 --> 01:34.620 server let's say was running at 90% utilization and this server over here is WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 22 01:29.620 --> 01:34.620 server let's say was running at 90% utilization and this server over here is 23 01:34.620 --> 01:39.300 running at 10% of the resources, well there was no way for this server to 24 01:39.300 --> 01:47.260 access the resources that are over here on the server that is not very highly 25 01:47.260 --> 01:53.020 loaded. But in this situation we absolutely can manage it this way. And so 26 01:53.020 --> 01:57.780 we can have virtual machines on the host that are running at 10% virtual 27 01:57.780 --> 02:02.260 machines that are running at 90% and in the end it's the physical resources WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 27 01:57.780 --> 02:02.260 machines that are running at 90% and in the end it's the physical resources 28 02:02.260 --> 02:02.860 that 29 02:02.860 --> 02:10.580 matter more so than the virtual resources. So how many virtual machines can run 30 02:10.580 --> 02:10.980 on 31 02:10.980 --> 02:17.990 a single host? Well the answer with all good questions is it depends. It 32 02:17.990 --> 02:18.460 depends 33 02:18.460 --> 02:23.700 because this virtual machine over here is consuming a real amount of memory a 34 02:23.700 --> 02:28.500 real amount of CPU cycles and all of these different resource components. And 35 02:28.500 --> 02:33.100 so once we've exhausted the physical resources by deploying virtual machines WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 35 02:28.500 --> 02:33.100 so once we've exhausted the physical resources by deploying virtual machines 36 02:33.100 --> 02:38.780 that's what defines the limit. So I might see a host that supports 10 to 15 37 02:38.780 --> 02:42.540 virtual machines. I would say in my experience this is a pretty common number 38 02:42.540 --> 02:48.420 that we might expect to see. But I might also have a very large server with an 39 02:48.420 --> 02:54.180 enormous number of CPU and memory types of resources and so maybe we've got 30 40 02:54.180 --> 02:54.300 to 41 02:54.300 --> 02:59.180 40 virtual machines on here and we could even go as low as one virtual machine 42 02:59.180 --> 02:59.420 on 43 02:59.420 --> 03:03.860 the host. Say well why in the world would we do that at that point we're back WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 43 02:59.420 --> 03:03.860 the host. Say well why in the world would we do that at that point we're back 44 03:03.860 --> 03:04.060 to a 45 03:04.060 --> 03:08.780 one-to-one relationship between applications and hosts and there's 46 03:08.780 --> 03:12.100 actually a few reasons for this. First of all the application might require it 47 03:12.100 --> 03:12.580 but 48 03:12.580 --> 03:17.780 second of all we actually get benefits tied to virtual machines that we could 49 03:17.780 --> 03:21.380 accomplish this way rather than installing the application and operating 50 03:21.380 --> 03:26.460 system directly to the hardware we install it as a virtual machine even 51 03:26.460 --> 03:31.460 though it will be the only virtual machine that runs. One of those advantages WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 51 03:26.460 --> 03:31.460 though it will be the only virtual machine that runs. One of those advantages 52 03:31.460 --> 03:36.900 that we can take it will take advantage of I suppose is the idea of migration. 53 03:36.900 --> 03:43.980 Virtual machines are software meaning that we can just move this software 54 03:43.980 --> 03:44.460 around we 55 03:44.460 --> 03:48.820 can move it around because it's just a bunch of zeros and ones on my desk and 56 03:48.820 --> 03:54.980 in memory. So when we think about having multiple hosts I might have a virtual 57 03:54.980 --> 03:59.340 host here but I'm probably going to have more than one virtual host it's pretty 58 03:59.340 --> 04:04.460 common to have at least a handful if not potentially even dozens of virtual WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 58 03:59.340 --> 04:04.460 common to have at least a handful if not potentially even dozens of virtual 59 04:04.460 --> 04:08.940 hosts depending on the size of the data center. And so maybe this virtual host 60 04:08.940 --> 04:13.980 is sitting here running at 90% resource utilization and this host over here is 61 04:13.980 --> 04:19.660 running at let's just actually use more realistic like a 30% utilization. So 62 04:19.660 --> 04:24.180 this is that same situation where we couldn't do anything about this when it 63 04:24.180 --> 04:29.460 was a bare metal architecture. Well now we have let's say 15 virtual machines 64 04:29.460 --> 04:35.100 running on this host over here and 15 virtual machines running over here. And WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 64 04:29.460 --> 04:35.100 running on this host over here and 15 virtual machines running over here. And 65 04:35.100 --> 04:38.060 not all virtual machines are created equal some of them are going to consume 66 04:38.060 --> 04:41.800 more resources and so even though we have the same number where you see that we 67 04:41.800 --> 04:41.900 're 68 04:41.900 --> 04:45.740 consuming vastly different amounts of resources assuming these hosts are 69 04:45.740 --> 04:49.020 built identically. There's nothing saying that they have to be for example 70 04:49.020 --> 04:54.060 this could have maybe 256 gig of memory on the left and this one over here 71 04:54.060 --> 04:58.500 might have 512 gig. We just don't know how exactly it's going to be built out 72 04:58.500 --> 05:03.380 but we've got all kinds of factors to consider in all of this. So what might we WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 72 04:58.500 --> 05:03.380 but we've got all kinds of factors to consider in all of this. So what might we 73 05:03.380 --> 05:09.300 do in this situation? Well what we could do is consider migrating maybe two to 74 05:09.300 --> 05:14.100 three virtual machines from one host to the other. Can we do this? Well 75 05:14.100 --> 05:17.740 absolutely in fact we support two different options we could do a cold 76 05:17.740 --> 05:24.860 migration which requires us to shut the virtual machine down and then we spin 77 05:24.860 --> 05:29.740 it back up we turn it on on a new host. The idea here is that the virtual 78 05:29.740 --> 05:35.500 machine technically lives off of the servers here on the storage array. This WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 78 05:29.740 --> 05:35.500 machine technically lives off of the servers here on the storage array. This 79 05:35.500 --> 05:39.770 is where the files the ones and zeros for the virtual machines are stored and 80 05:39.770 --> 05:40.020 so 81 05:40.020 --> 05:45.420 as long as they both have access to the same storage array then these two hosts 82 05:45.420 --> 05:49.900 can both access that virtual machine so I could turn it off on this host I 83 05:49.900 --> 05:50.060 could 84 05:50.060 --> 05:54.260 turn it on on this host over here and that's known as a cold migration it 85 05:54.260 --> 05:57.900 involves again shutting down the virtual machine. But here's the crazy 86 05:57.900 --> 06:02.020 thing even better than this and feels like black magic is we can actually do a WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 86 05:57.900 --> 06:02.020 thing even better than this and feels like black magic is we can actually do a 87 06:02.020 --> 06:07.780 live migration. Forget the idea of shutting the virtual machine down simply 88 06:07.780 --> 06:13.820 move the virtual machine from one host to the other while staying online the 89 06:13.820 --> 06:19.860 entire time. How on earth do we do this? Well the way this works is again the 90 06:19.860 --> 06:23.460 virtual machine is going to live from a ones and zeros perspective up here on 91 06:23.460 --> 06:29.780 the storage array but it also is going to live here in memory in RAM and so if 92 06:29.780 --> 06:29.860 I 93 06:29.860 --> 06:35.540 can move these ones and zeros over to this host and in and in a as real time as WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 93 06:29.860 --> 06:35.540 can move these ones and zeros over to this host and in and in a as real time as 94 06:35.540 --> 06:40.500 possible shut the virtual machine down on this side and spin it back up on the 95 06:40.500 --> 06:45.140 other side well at that point the virtual machine has not stopped running that 96 06:45.140 --> 06:51.420 entire time and this is the concept of a live migration. Very cool and very 97 06:51.420 --> 06:57.380 powerful it allows me to move virtual machines around and in a way that we 98 06:57.380 --> 07:02.900 barely drop a ping in a lot of cases we don't even drop a ping and so this is a WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 98 06:57.380 --> 07:02.900 barely drop a ping in a lot of cases we don't even drop a ping and so this is a 99 07:02.900 --> 07:10.340 seamless migration to our end users. If they're using the application that's 100 07:10.340 --> 07:14.060 hosted by this virtual machine they shouldn't even know that it moved from 101 07:14.060 --> 07:19.620 one physical host to another physical host. Pretty crazy stuff when we think 102 07:19.620 --> 07:26.260 about it and so because of this again we see some very big benefits to running 103 07:26.260 --> 07:26.540 as 104 07:26.540 --> 07:30.460 virtual machines as opposed to just deploying on to bare metal and this is WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 104 07:26.540 --> 07:30.460 virtual machines as opposed to just deploying on to bare metal and this is 105 07:30.460 --> 07:33.980 again why we might consider doing something like this even though it might 106 07:33.980 --> 07:39.420 be silly at first to think about running a single virtual machine on a physical 107 07:39.420 --> 07:44.220 server a physical host but instead now we've converted to a virtual machine and 108 07:44.220 --> 07:49.220 we get these benefits. For example if I'm going to perform an upgrade or even 109 07:49.220 --> 07:55.100 just a standard maintenance on the host itself well then I can move all the 110 07:55.100 --> 07:59.620 virtual machines to other hosts perform that upgrade or perform the maintenance 111 07:59.620 --> 08:03.740 and then migrate the virtual machines back and again it was seamless to the WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 111 07:59.620 --> 08:03.740 and then migrate the virtual machines back and again it was seamless to the 112 08:03.740 --> 08:09.620 users. I can also perform this concept of dynamic resource management so what 113 08:09.620 --> 08:13.900 we just described where we had a situation where one of our hosts was 114 08:13.900 --> 08:18.900 heavily loaded the other one was lightly loaded. Some of the virtual machine 115 08:18.900 --> 08:23.740 software packages out there will do this on its own dynamically without us 116 08:23.740 --> 08:27.460 intervening. They'll just slide the virtual machines around and make sure that 117 08:27.460 --> 08:32.700 we're maximizing our resources and lastly we do have the concept of surviving WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 117 08:27.460 --> 08:32.700 we're maximizing our resources and lastly we do have the concept of surviving 118 08:32.700 --> 08:37.970 hardware failure as well. Now depending on how the hardware fails if we just 119 08:37.970 --> 08:38.060 all 120 08:38.060 --> 08:42.980 of a sudden lose one of these hosts we might have to rely on cold migration for 121 08:42.980 --> 08:47.060 this other host to spin up the virtual machine but again a lot of software 122 08:47.060 --> 08:52.500 packages that exist out there will help us to do this even in this situation in 123 08:52.500 --> 08:58.900 a seamless live migration style using this concept of high availability. To run 124 08:58.900 --> 09:02.380 essentially a backup instance of the virtual machine over here so that if this WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 124 08:58.900 --> 09:02.380 essentially a backup instance of the virtual machine over here so that if this 125 09:02.380 --> 09:08.220 host goes down we immediately activate this backup instance. So some pretty 126 09:08.220 --> 09:12.740 crazy technology that exists here in the virtual space but again virtual 127 09:12.740 --> 09:17.740 machines enable all of this simply by converting the idea of our physical 128 09:17.740 --> 09:23.700 servers physical bare metal servers to software and then we think about all 129 09:23.700 --> 09:27.300 the things we can do with software we can even copy and paste virtual machines 130 09:27.300 --> 09:31.220 and use them for templates and all kinds of things everything that ties back to WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 130 09:27.300 --> 09:31.220 and use them for templates and all kinds of things everything that ties back to 131 09:31.220 --> 09:36.620 the fact that now that's represented by software.