1 1 00:00:00,179 --> 00:00:02,760 SOA and microservices. 2 2 00:00:02,760 --> 00:00:04,500 In this lesson, we're going to start talking 3 3 00:00:04,500 --> 00:00:07,080 about the way systems are designed these days 4 4 00:00:07,080 --> 00:00:10,650 by using service-oriented architecture and microservices. 5 5 00:00:10,650 --> 00:00:13,320 Now, in the old days, the legacy way of doing things, 6 6 00:00:13,320 --> 00:00:15,930 we would build these huge monolithic networks 7 7 00:00:15,930 --> 00:00:17,190 and we'd have to get our routing 8 8 00:00:17,190 --> 00:00:19,140 and our security and our servers. 9 9 00:00:19,140 --> 00:00:20,550 We'd put all this stuff together 10 10 00:00:20,550 --> 00:00:23,610 to build these huge networks to perform one function. 11 11 00:00:23,610 --> 00:00:25,710 Everything was very tightly coupled 12 12 00:00:25,710 --> 00:00:26,970 and so when something went wrong, 13 13 00:00:26,970 --> 00:00:29,610 we had to identify exactly what it was. 14 14 00:00:29,610 --> 00:00:32,040 Well, these days, it becomes a lot easier 15 15 00:00:32,040 --> 00:00:34,230 for us to build things because we're using a lot more 16 16 00:00:34,230 --> 00:00:36,630 of this service-oriented architecture. 17 17 00:00:36,630 --> 00:00:38,850 When we talk about service-oriented architecture, 18 18 00:00:38,850 --> 00:00:40,440 this is the combination of lots 19 19 00:00:40,440 --> 00:00:42,720 of different little pieces, like the system, 20 20 00:00:42,720 --> 00:00:45,480 the service, the platform, the practice, the people, 21 21 00:00:45,480 --> 00:00:48,180 the architecture, the process, and the integration 22 22 00:00:48,180 --> 00:00:50,250 and each of these can be operated individually 23 23 00:00:50,250 --> 00:00:52,140 so they're not tightly coupled anymore. 24 24 00:00:52,140 --> 00:00:54,780 Instead, we call this a loose coupling. 25 25 00:00:54,780 --> 00:00:55,613 Now, when I talk 26 26 00:00:55,613 --> 00:00:58,500 about service-oriented architecture or SOA, 27 27 00:00:58,500 --> 00:01:01,260 this is a software architecture where the components 28 28 00:01:01,260 --> 00:01:04,500 of the solution are conceived as loosely coupled services, 29 29 00:01:04,500 --> 00:01:07,950 not dependent on a single platform type or technology. 30 30 00:01:07,950 --> 00:01:10,590 By doing this, each individual piece can be built 31 31 00:01:10,590 --> 00:01:13,260 on its own and tested on its own and that way, 32 32 00:01:13,260 --> 00:01:15,630 there's no dependencies existing between these. 33 33 00:01:15,630 --> 00:01:16,860 It makes it a lot easier 34 34 00:01:16,860 --> 00:01:20,220 for us to build applications and reuse components. 35 35 00:01:20,220 --> 00:01:22,800 Now, each service is going to take defined inputs 36 36 00:01:22,800 --> 00:01:24,600 and produce defined outputs. 37 37 00:01:24,600 --> 00:01:25,890 Essentially, we call this 38 38 00:01:25,890 --> 00:01:28,530 like a black box type of architecture. 39 39 00:01:28,530 --> 00:01:31,170 I'm going to say this thing does this function 40 40 00:01:31,170 --> 00:01:32,910 and it takes these things as inputs, 41 41 00:01:32,910 --> 00:01:35,340 and it's going to give you that thing as the output. 42 42 00:01:35,340 --> 00:01:38,280 So if I have this box, it's going to do some math problem, 43 43 00:01:38,280 --> 00:01:39,720 you're going to give it two inputs 44 44 00:01:39,720 --> 00:01:41,070 and it's going to add those things together 45 45 00:01:41,070 --> 00:01:42,180 and give you an output. 46 46 00:01:42,180 --> 00:01:43,290 That would be an example 47 47 00:01:43,290 --> 00:01:46,890 of a very basic service-oriented architecture example. 48 48 00:01:46,890 --> 00:01:48,150 Now, when we start dealing 49 49 00:01:48,150 --> 00:01:50,010 with service-oriented architecture, 50 50 00:01:50,010 --> 00:01:51,990 we use this idea of decoupling. 51 51 00:01:51,990 --> 00:01:55,020 We decouple these services into these different layers. 52 52 00:01:55,020 --> 00:01:56,490 Now, everything is connected together 53 53 00:01:56,490 --> 00:01:58,680 by providing a specific type of input 54 54 00:01:58,680 --> 00:02:01,050 and they're going to provide you with a particular structure 55 55 00:02:01,050 --> 00:02:03,090 for that output that you're expecting. 56 56 00:02:03,090 --> 00:02:05,490 Everything in between is really a black box. 57 57 00:02:05,490 --> 00:02:06,990 We don't really care what happens as long 58 58 00:02:06,990 --> 00:02:08,340 as we get what we want. 59 59 00:02:08,340 --> 00:02:10,290 This allows us to essentially have a bunch 60 60 00:02:10,290 --> 00:02:13,350 of building blocks that we can use at these different layers 61 61 00:02:13,350 --> 00:02:15,090 and to do these different functions. 62 62 00:02:15,090 --> 00:02:17,910 For example, we have a presentation layer at the top 63 63 00:02:17,910 --> 00:02:20,220 or we have a business process layer underneath that. 64 64 00:02:20,220 --> 00:02:21,510 We have service component layers. 65 65 00:02:21,510 --> 00:02:23,550 We have messaging layers that have a connection 66 66 00:02:23,550 --> 00:02:25,590 to legacy systems, all the way down 67 67 00:02:25,590 --> 00:02:28,890 to the underlying enterprise information technology systems. 68 68 00:02:28,890 --> 00:02:30,900 And each of these can be designed, built 69 69 00:02:30,900 --> 00:02:34,320 and tested individually in a decoupled manner. 70 70 00:02:34,320 --> 00:02:36,660 When we look at these services, they're going to be defined 71 71 00:02:36,660 --> 00:02:39,480 within the scope of functional business requirements 72 72 00:02:39,480 --> 00:02:42,480 and these things can then be reused for different purposes. 73 73 00:02:42,480 --> 00:02:43,980 As you look at these different services, 74 74 00:02:43,980 --> 00:02:45,180 you're going to look at them and go, 75 75 00:02:45,180 --> 00:02:48,180 this service is going to be used for this function. 76 76 00:02:48,180 --> 00:02:49,980 This is a SMS program. 77 77 00:02:49,980 --> 00:02:53,160 It's going to take some message and send it out as a text. 78 78 00:02:53,160 --> 00:02:55,500 This program might be something that's going to get things 79 79 00:02:55,500 --> 00:02:56,370 in through email 80 80 00:02:56,370 --> 00:02:58,980 and then it's going to output it in this other format. 81 81 00:02:58,980 --> 00:03:00,810 Whatever it is you're actually going to build, 82 82 00:03:00,810 --> 00:03:03,360 it's all based on your functional business requirements 83 83 00:03:03,360 --> 00:03:06,060 and allows you to reuse them time and time again. 84 84 00:03:06,060 --> 00:03:07,770 Now, one of the things we have to consider 85 85 00:03:07,770 --> 00:03:09,630 is that if we have all of these services 86 86 00:03:09,630 --> 00:03:11,730 that are being built in a decoupled manner, 87 87 00:03:11,730 --> 00:03:13,890 how do we get them to communicate together? 88 88 00:03:13,890 --> 00:03:15,270 Well, we're going to use something known 89 89 00:03:15,270 --> 00:03:18,300 as the Enterprise Service Bus or ESB. 90 90 00:03:18,300 --> 00:03:21,120 This is a common component of SOA architectures 91 91 00:03:21,120 --> 00:03:23,310 that helps us facilitate this decoupled service 92 92 00:03:23,310 --> 00:03:25,260 to service communication. 93 93 00:03:25,260 --> 00:03:27,600 When you look at service-oriented architecture, 94 94 00:03:27,600 --> 00:03:30,750 it is going to be looked at from an overall design architecture 95 95 00:03:30,750 --> 00:03:33,030 and it's a way for us to map the business workflows 96 96 00:03:33,030 --> 00:03:35,220 to the IT systems to support them. 97 97 00:03:35,220 --> 00:03:37,440 Again, our whole function here is to figure out 98 98 00:03:37,440 --> 00:03:39,270 what is the process we're going to do? 99 99 00:03:39,270 --> 00:03:41,670 What is the business process that we need to mimic 100 100 00:03:41,670 --> 00:03:43,620 and based on that business process and workflow, 101 101 00:03:43,620 --> 00:03:45,690 we can then pull all these different pieces 102 102 00:03:45,690 --> 00:03:47,008 and services together 103 103 00:03:47,008 --> 00:03:50,550 with those IT systems that will support those services. 104 104 00:03:50,550 --> 00:03:52,050 Now, one of the things that really helps us 105 105 00:03:52,050 --> 00:03:54,660 with this is the idea of microservices. 106 106 00:03:54,660 --> 00:03:57,120 Microservices are software architectures 107 107 00:03:57,120 --> 00:03:59,160 where the components of the solution are conceived 108 108 00:03:59,160 --> 00:04:00,990 as a highly decoupled service, 109 109 00:04:00,990 --> 00:04:04,523 not dependent on a single platform type or technology. 110 110 00:04:04,523 --> 00:04:07,050 Again, by using these microservices 111 111 00:04:07,050 --> 00:04:08,940 and designing our systems in this way, 112 112 00:04:08,940 --> 00:04:10,740 we are actually having a paradigm shift. 113 113 00:04:10,740 --> 00:04:12,840 We're thinking about doing things differently 114 114 00:04:12,840 --> 00:04:15,420 in terms of application development. 115 115 00:04:15,420 --> 00:04:18,090 When you're using a microservice architecture, 116 116 00:04:18,090 --> 00:04:18,990 it's going to have some 117 117 00:04:18,990 --> 00:04:21,660 of the same general principles as SOA. 118 118 00:04:21,660 --> 00:04:23,580 It sounds a lot alike, doesn't it? 119 119 00:04:23,580 --> 00:04:25,380 Now, when we look at these, they're going to contain things 120 120 00:04:25,380 --> 00:04:27,360 like self-contained service modules, 121 121 00:04:27,360 --> 00:04:29,250 each one performing a single function 122 122 00:04:29,250 --> 00:04:31,320 with clearly defined inputs and outputs. 123 123 00:04:31,320 --> 00:04:33,150 Sounds a lot like SOA, right? 124 124 00:04:33,150 --> 00:04:34,890 We're also going to then take those services 125 125 00:04:34,890 --> 00:04:37,650 and apply them to the design of network applications, 126 126 00:04:37,650 --> 00:04:39,330 such as an order processing system, 127 127 00:04:39,330 --> 00:04:40,800 a video streaming service, 128 128 00:04:40,800 --> 00:04:44,400 a messaging system, an email system, a file support system. 129 129 00:04:44,400 --> 00:04:46,230 Whatever those things are, we can take them, 130 130 00:04:46,230 --> 00:04:49,140 network them together, and create a larger service. 131 131 00:04:49,140 --> 00:04:52,110 So you may be asking yourself, what's really the difference 132 132 00:04:52,110 --> 00:04:54,450 between SOA and microservices 133 133 00:04:54,450 --> 00:04:57,210 because they sound very, very similar. 134 134 00:04:57,210 --> 00:05:00,420 Well, when you see SOA, I want you to remember that SOA, 135 135 00:05:00,420 --> 00:05:02,100 it allows applications to be built 136 136 00:05:02,100 --> 00:05:05,010 from services with some interdependencies. 137 137 00:05:05,010 --> 00:05:06,990 Now, when you start dealing with microservices, 138 138 00:05:06,990 --> 00:05:07,920 on the other hand, 139 139 00:05:07,920 --> 00:05:09,900 you're going to have microservices that are capable 140 140 00:05:09,900 --> 00:05:13,230 of being developed, tested, and deployed independently. 141 141 00:05:13,230 --> 00:05:15,870 These microservices are more easily scalable 142 142 00:05:15,870 --> 00:05:17,640 than a big monolithic app 143 143 00:05:17,640 --> 00:05:20,400 because only the necessary service modules you need 144 144 00:05:20,400 --> 00:05:22,170 will need to be scaled up to support it 145 145 00:05:22,170 --> 00:05:24,480 rather than having to provision additional resources 146 146 00:05:24,480 --> 00:05:27,150 for the entire application infrastructure. 147 147 00:05:27,150 --> 00:05:29,610 So when it comes down to what is the difference 148 148 00:05:29,610 --> 00:05:32,220 between SOA and microservices, remember, 149 149 00:05:32,220 --> 00:05:34,530 if we take services and we put them all together 150 150 00:05:34,530 --> 00:05:35,850 in some kind of business process 151 151 00:05:35,850 --> 00:05:39,300 and we create interdependencies, that is SOA, 152 152 00:05:39,300 --> 00:05:41,070 that is a service-oriented architecture 153 153 00:05:41,070 --> 00:05:43,620 where everything that runs that is a service 154 154 00:05:43,620 --> 00:05:45,180 and we connect them all together. 155 155 00:05:45,180 --> 00:05:46,710 When we start dealing with microservices, 156 156 00:05:46,710 --> 00:05:47,970 they're independent. 157 157 00:05:47,970 --> 00:05:51,420 They are one individual thing that's going to be developed, 158 158 00:05:51,420 --> 00:05:53,010 tested, and deployed. 159 159 00:05:53,010 --> 00:05:55,230 And so really, it's all about interdependency. 160 160 00:05:55,230 --> 00:05:57,930 When you're dealing with SOA, you have those connections. 161 161 00:05:57,930 --> 00:06:00,413 When you're dealing with microservices, you don't.