1 00:00:02,290 --> 00:00:04,730 So what is Docker Compose? 2 00:00:04,730 --> 00:00:07,010 It's really easy to understand in the end. 3 00:00:07,010 --> 00:00:11,400 Docker Compose is a tool that allows you to replace 4 00:00:11,400 --> 00:00:14,660 Docker build and Docker run commands 5 00:00:14,660 --> 00:00:16,800 and they're not just one Docker build 6 00:00:16,800 --> 00:00:18,510 and one Docker run command, 7 00:00:18,510 --> 00:00:21,130 but potentially multiple Docker build 8 00:00:21,130 --> 00:00:26,030 and Docker run commands with just one configuration file 9 00:00:26,030 --> 00:00:29,300 and then a set of orchestration commands 10 00:00:29,300 --> 00:00:33,890 to start all those services, all these containers at once 11 00:00:33,890 --> 00:00:37,430 and build all necessary images, if it should be required 12 00:00:37,430 --> 00:00:40,680 and you then also can use one command to stop everything 13 00:00:40,680 --> 00:00:44,060 and bring everything down and that will be great 14 00:00:44,060 --> 00:00:47,220 because whilst you can, of course already 15 00:00:47,220 --> 00:00:51,370 store Docker commands in any text file of your choice, 16 00:00:51,370 --> 00:00:54,240 and then just copy and paste them into your terminal, 17 00:00:54,240 --> 00:00:56,880 whilst you can already do that of course, 18 00:00:56,880 --> 00:00:59,090 this is not super convenient. 19 00:00:59,090 --> 00:01:03,490 And with Docker Compose, that will be much more convenient 20 00:01:04,930 --> 00:01:07,040 because with Docker Compose, you will have 21 00:01:07,040 --> 00:01:11,540 one configuration file using a clearly defined language 22 00:01:11,540 --> 00:01:13,400 which you can share with anyone 23 00:01:13,400 --> 00:01:17,410 and then it's just one command, no command copy and pasting 24 00:01:17,410 --> 00:01:21,270 just one command which will leverage this configuration file 25 00:01:21,270 --> 00:01:23,940 and which will then bring up or bring down 26 00:01:23,940 --> 00:01:27,290 your entire multicontainer application. 27 00:01:27,290 --> 00:01:29,150 Of course, just as a side note, 28 00:01:29,150 --> 00:01:30,910 you can also use Docker Compose 29 00:01:30,910 --> 00:01:32,980 in a single container application, 30 00:01:32,980 --> 00:01:36,630 it just shines the most if you have multiple containers 31 00:01:36,630 --> 00:01:40,050 because there, you can simply save a lot of extra commands 32 00:01:40,050 --> 00:01:42,150 and therefore time. 33 00:01:42,150 --> 00:01:45,080 I also briefly wanna highlight what Docker Compose 34 00:01:45,080 --> 00:01:48,410 is not though just to make this also clear. 35 00:01:48,410 --> 00:01:51,580 Docker Compose will not replace Docker files 36 00:01:51,580 --> 00:01:53,360 for custom images. 37 00:01:53,360 --> 00:01:55,350 You will see this in this module, 38 00:01:55,350 --> 00:01:58,730 Docker Compose works together with Docker files. 39 00:01:58,730 --> 00:02:01,230 It does not replace them. 40 00:02:01,230 --> 00:02:06,020 Docker Compose also does not replace images or containers. 41 00:02:06,020 --> 00:02:08,310 It just makes working with them easier, 42 00:02:08,310 --> 00:02:11,620 it makes launching containers ways easier 43 00:02:11,620 --> 00:02:15,410 and also important, Docker Compose is not suited 44 00:02:15,410 --> 00:02:18,690 for managing multiple containers on different hosts. 45 00:02:18,690 --> 00:02:21,930 At least that's not its primary strength. 46 00:02:21,930 --> 00:02:24,640 Docker Compose is really great for managing 47 00:02:24,640 --> 00:02:27,820 multiple containers on one and the same host 48 00:02:27,820 --> 00:02:30,950 and we'll talk about deploying containers to single 49 00:02:30,950 --> 00:02:33,840 and multiple hosts in the deployment section. 50 00:02:33,840 --> 00:02:35,670 For the moment we're running everything on 51 00:02:35,670 --> 00:02:38,160 our hosting machine, which is just one machine 52 00:02:38,160 --> 00:02:40,910 and therefore one host and therefore at the moment, 53 00:02:40,910 --> 00:02:43,650 Docker Compose is perfect and in general, 54 00:02:43,650 --> 00:02:47,530 it's a super powerful Docker tool, which you will use a lot 55 00:02:47,530 --> 00:02:51,350 in reality for development, but also for things 56 00:02:51,350 --> 00:02:53,540 beyond development, as you will learn 57 00:02:53,540 --> 00:02:55,090 throughout this course. 58 00:02:55,090 --> 00:02:58,170 Okay, so Docker Compose sounds quite interesting, 59 00:02:58,170 --> 00:03:00,260 how do we get with it? 60 00:03:00,260 --> 00:03:04,420 You always start by writing a Docker Compose file. 61 00:03:04,420 --> 00:03:06,670 Unlike Docker without compose, 62 00:03:06,670 --> 00:03:10,670 it's not primarily about executing commands in the terminal. 63 00:03:10,670 --> 00:03:13,100 Instead the idea is that you can save time there 64 00:03:13,100 --> 00:03:15,390 and therefore you put a lot of configuration 65 00:03:15,390 --> 00:03:17,850 into this Docker Compose file. 66 00:03:17,850 --> 00:03:19,320 And in this file, 67 00:03:19,320 --> 00:03:22,510 you need just define a couple of core things, 68 00:03:22,510 --> 00:03:25,220 a couple of core components that make up 69 00:03:25,220 --> 00:03:27,273 your multicontainer application. 70 00:03:28,410 --> 00:03:31,760 The heart and most important element 71 00:03:31,760 --> 00:03:34,240 or thing you can define in a compose file 72 00:03:34,240 --> 00:03:36,940 and you must define in a compose file 73 00:03:36,940 --> 00:03:39,580 are the so-called services which in the end 74 00:03:39,580 --> 00:03:41,770 can be translated with containers 75 00:03:41,770 --> 00:03:45,130 that make up your multicontainer application. 76 00:03:45,130 --> 00:03:49,180 But then below every service you can configure that service. 77 00:03:49,180 --> 00:03:53,120 And when I say service here, I really just mean container. 78 00:03:53,120 --> 00:03:55,970 You can define which port should be published, 79 00:03:55,970 --> 00:03:58,900 which environment variables this container might need. 80 00:03:58,900 --> 00:04:01,470 You can define volumes that should be assigned 81 00:04:01,470 --> 00:04:02,530 to this container. 82 00:04:02,530 --> 00:04:04,170 You can assign networks 83 00:04:04,170 --> 00:04:07,300 and you can do basically everything you can do with 84 00:04:07,300 --> 00:04:10,510 Docker command in the terminal otherwise, 85 00:04:10,510 --> 00:04:12,280 because the idea really is 86 00:04:12,280 --> 00:04:15,160 that we replace running these Docker commands 87 00:04:15,160 --> 00:04:18,610 in the terminal, that is the idea of compose. 88 00:04:18,610 --> 00:04:21,480 And therefore I'd say enough of the theory, 89 00:04:21,480 --> 00:04:25,460 let's get started and let's simply work on that project 90 00:04:25,460 --> 00:04:28,810 we built in the last module and let's use compose 91 00:04:28,810 --> 00:04:31,343 instead of running all these individual commands.