1 00:00:00,000 --> 00:00:09,440 In this video, you'll learn about Compose. 2 00:00:09,440 --> 00:00:10,440 So what is Compose? 3 00:00:10,440 --> 00:00:17,040 Well, Docker Compose and Popman Compose are used to run simple microservice-based applications 4 00:00:17,040 --> 00:00:18,840 based on a Compose file. 5 00:00:18,840 --> 00:00:23,200 And a Compose file is a complete definition of what you want to use. 6 00:00:23,200 --> 00:00:28,900 Now to use it, all the components of the containerized application are defined in this Compose file. 7 00:00:28,900 --> 00:00:32,220 And the docker-compose command is used to manage the application state. 8 00:00:32,220 --> 00:00:34,459 Let me show you. 9 00:00:34,459 --> 00:00:36,419 So I need to do a couple of things. 10 00:00:36,419 --> 00:00:42,980 First, I need sudo apt install docker-compose. 11 00:00:42,980 --> 00:00:45,900 It's a separate installation, as you can see. 12 00:00:45,900 --> 00:00:47,259 Then I need my Compose file. 13 00:00:47,259 --> 00:00:51,320 Well, I'm going to borrow it from a Git repository. 14 00:00:51,320 --> 00:00:55,619 So that's a Git repository I'm using for my containers course. 15 00:00:55,619 --> 00:01:03,320 GitHub.com slash Sander van Vugt slash containers should give access to it. 16 00:01:03,320 --> 00:01:06,440 Oh, forgetting git clone. 17 00:01:06,440 --> 00:01:09,040 Of course, that's the right command, git clone. 18 00:01:09,040 --> 00:01:16,639 So now when I go in this containers directory, we can see that there is a directory with 19 00:01:16,639 --> 00:01:20,180 the name WordPress MySQL. 20 00:01:20,180 --> 00:01:22,559 So what is in WordPress MySQL? 21 00:01:22,559 --> 00:01:25,199 There is a docker-compose.yaml. 22 00:01:25,779 --> 00:01:30,820 Docker-compose is using YAML files, and here you can see what it is doing. 23 00:01:30,820 --> 00:01:39,260 Okay, I really rather use Vim, but let's just go for docker-compose.yaml in nano. 24 00:01:39,260 --> 00:01:41,540 After all, editor is an editor. 25 00:01:41,540 --> 00:01:42,540 So what do we see? 26 00:01:42,540 --> 00:01:43,620 We see a version. 27 00:01:43,620 --> 00:01:45,940 We see that it defines a service. 28 00:01:45,940 --> 00:01:49,779 And every service is using a specific container image. 29 00:01:49,779 --> 00:01:54,419 And the nice thing about this Compose file is that you can provide information on how 30 00:01:54,639 --> 00:01:56,360 the image should be started. 31 00:01:56,360 --> 00:01:58,000 So we define a volume. 32 00:01:58,000 --> 00:02:00,720 We define some environment variables. 33 00:02:00,720 --> 00:02:05,959 We define some ports, and that is all that you are going to need. 34 00:02:05,959 --> 00:02:10,880 And the next thing is docker-compose up, and that will bring it up. 35 00:02:10,880 --> 00:02:16,360 And here you can see that the container is trying to get up. 36 00:02:16,360 --> 00:02:18,119 And oh boy, this doesn't work. 37 00:02:18,119 --> 00:02:19,520 Now, can we fix it? 38 00:02:19,520 --> 00:02:21,600 I think we can fix it. 39 00:02:21,600 --> 00:02:23,960 The problem here is an interesting problem. 40 00:02:24,000 --> 00:02:29,220 We talked about this before, and the problem is that it's telling me that it doesn't find 41 00:02:29,220 --> 00:02:36,020 a matching manifest for Linux ARM64 V8 in the manifest for WordPress. 42 00:02:36,020 --> 00:02:37,020 Now what is the case? 43 00:02:37,020 --> 00:02:45,660 The case is that I'm referring to MySQL 5.7, and that seems to be doing all right. 44 00:02:45,660 --> 00:02:50,940 Let me make that latest, and WordPress latest, well, apparently there is no ARM image. 45 00:02:50,940 --> 00:02:51,940 So you know what? 46 00:02:51,940 --> 00:02:58,559 I'm going to change that to nginx, colon, latest, because really this is not about getting 47 00:02:58,559 --> 00:03:01,720 it all to work and getting the perfect microservice. 48 00:03:01,720 --> 00:03:05,580 We want to understand what docker-compose is all about, right? 49 00:03:05,580 --> 00:03:11,119 So writing my changes, and then I'm doing my docker-compose up, and this time hopefully 50 00:03:11,119 --> 00:03:14,000 it is going better. 51 00:03:14,000 --> 00:03:24,160 Well, almost, there's a small typo in the name of the image. 52 00:03:24,160 --> 00:03:28,520 And there you can see it starts pulling the database image, and once it is done doing 53 00:03:28,520 --> 00:03:35,800 so, it will start pulling the nginx image, and the result will be a complete microservice 54 00:03:35,800 --> 00:03:39,039 application managed by docker-compose. 55 00:03:39,039 --> 00:03:43,800 I didn't do it the nice way because I didn't run it in the detached mode, and that is why 56 00:03:43,800 --> 00:03:47,800 we are looking at the screen right now. 57 00:03:47,800 --> 00:03:51,080 Control-C is an easy way to get out of there, and it will stop it. 58 00:03:51,080 --> 00:03:53,000 That's what you need to know about docker-compose.