WEBVTT 00:00.386 --> 00:01.470 -: In the last section, 00:01.470 --> 00:04.140 we tried to answer the question of why use Docker? 00:04.140 --> 00:05.790 And we eventually said that we use Docker 00:05.790 --> 00:08.100 because it makes it really easy to install 00:08.100 --> 00:10.770 and run new software on our computer. 00:10.770 --> 00:13.650 We're not gonna try to answer the other big question here, 00:13.650 --> 00:15.810 which is, what is Docker? 00:15.810 --> 00:19.080 Well, this question is a lot more challenging to answer. 00:19.080 --> 00:21.300 Anytime you see someone refer to Docker 00:21.300 --> 00:23.130 in a blog post or an article 00:23.130 --> 00:25.350 or a forum or wherever it might be, 00:25.350 --> 00:28.320 they're kind of making reference to an entire ecosystem 00:28.320 --> 00:32.190 of different projects, tools, and pieces of software. 00:32.190 --> 00:35.940 So if someone says, "oh yeah, I use Docker on my project" 00:35.940 --> 00:39.570 they might be referring to Docker client or a Docker server. 00:39.570 --> 00:42.180 They might be referring to Docker hub or Docker Compose. 00:42.180 --> 00:45.990 Again, these are all projects, tools, pieces of software 00:45.990 --> 00:49.860 that come together to form a platform or ecosystem 00:49.860 --> 00:53.910 around creating and running something called containers. 00:53.910 --> 00:56.310 And so your immediate question might be, 00:56.310 --> 00:58.440 Okay well what's a container? 00:58.440 --> 00:59.430 That's a good question 00:59.430 --> 01:00.330 and that's a question 01:00.330 --> 01:01.620 that we're going to be trying to answer 01:01.620 --> 01:03.540 throughout this entire course. 01:03.540 --> 01:06.540 Just a moment ago, when I ran that command at my terminal 01:06.540 --> 01:08.880 of Docker run Redis, 01:08.880 --> 01:11.910 it went through a little series of actions behind the scenes 01:11.910 --> 01:14.370 and we're going to examine that entire series of actions 01:14.370 --> 01:15.750 very closely over time. 01:15.750 --> 01:16.583 But for right now, 01:16.583 --> 01:19.560 let me give you two important pieces of terminology. 01:19.560 --> 01:21.090 When I ran that command, 01:21.090 --> 01:23.580 something called the Docker CLI reached out 01:23.580 --> 01:25.770 to something called the Docker hub 01:25.770 --> 01:29.610 and it downloaded a single file called an image. 01:29.610 --> 01:32.940 An image is a single file containing all the dependencies 01:32.940 --> 01:34.680 and all the configuration required 01:34.680 --> 01:37.260 to run a very specific program. 01:37.260 --> 01:39.630 For example, Redis, which is what the image 01:39.630 --> 01:42.360 that I just downloaded was supposed to run. 01:42.360 --> 01:45.660 This is a single file that gets stored on your hard drive. 01:45.660 --> 01:46.800 And at some point in time, 01:46.800 --> 01:48.540 you can use this image to create 01:48.540 --> 01:50.193 something called a container. 01:51.030 --> 01:53.640 A container is an instance of an image 01:53.640 --> 01:55.539 and you can kind of think of it 01:55.539 --> 01:57.600 as being like a running program. 01:57.600 --> 01:59.580 We're gonna go into great detail over time, 01:59.580 --> 02:03.390 over behind to learn exactly how a container works exactly. 02:03.390 --> 02:05.610 But right now, all we really need to understand 02:05.610 --> 02:07.740 is that a container is a program 02:07.740 --> 02:10.980 with its own isolated set of hardware resources. 02:10.980 --> 02:12.660 So it kind of has its own little set 02:12.660 --> 02:14.340 or its own little space of memory, 02:14.340 --> 02:17.610 has its own little space of networking technology 02:17.610 --> 02:21.117 and its own little space of hard drive space as well. 02:21.117 --> 02:24.300 Okay, so I didn't really answer the question here 02:24.300 --> 02:26.280 of what Docker is, 02:26.280 --> 02:28.830 but we did learn at least that a reference to Docker 02:28.830 --> 02:30.510 is really talking about a whole collection 02:30.510 --> 02:32.100 of different projects and tools, 02:32.100 --> 02:35.430 and we also picked up two important pieces of terminology, 02:35.430 --> 02:37.980 a docker image and a container. 02:37.980 --> 02:39.570 Now these images and containers 02:39.570 --> 02:40.770 are the absolute backbone 02:40.770 --> 02:42.210 of what you and I are going to working with 02:42.210 --> 02:43.620 throughout the rest of this course. 02:43.620 --> 02:45.180 So let's take a quick pause right now. 02:45.180 --> 02:46.530 We're gonna come back to the next section 02:46.530 --> 02:48.210 and we're gonna start talking a little bit more 02:48.210 --> 02:50.820 about how we work with images and containers. 02:50.820 --> 02:53.270 So quick break and I'll see you in just a minute.