WEBVTT

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-: Throughout this course, we've been making use of images

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that have been created by other engineers.

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So for example, we have used,

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say the Hello World Image or Redis, or BusyBox.

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These are all images that were created by other engineers.

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We download them onto our local machine

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and then created a container out of them.

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At this point, we're gonna start to figure out

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how we can build our own custom images

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so that we can run our own applications

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inside of our own personalized containers.

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The process for making an image is somewhat straightforward.

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Like all things,

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you just have to learn a little bit of syntax.

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So here's what we're going to do to make our own image.

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We're gonna create something called a dockerfile.

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A dockerfile is essentially a plain text file

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that is going to have a couple of lines of configuration

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placed inside of it.

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This configuration is going to define

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how our container behaves,

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or more specifically what different programs

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it's going to contain

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and what it does when it starts up as a container.

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Once we create that dockerfile,

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we'll then pass it off to the docker client

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which you'll recall is the docker CLI

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that we've been using at our terminal.

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In turn, the docker client will provide the file

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to the docker server.

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The docker server is what is doing the heavy lifting for us.

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It's going to take the dockerfile,

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look at all the lines of configuration

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that we have inside of it,

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and then build a usable image

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that can then be used to start up a new container.

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Now the dockerfile is where

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all the complexity is going to sit.

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And like I just said a moment ago,

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it's not really gonna be the worst thing in the world.

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It's just about learning a couple of new commands.

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That's all.

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In fact, just about every dockerfile

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that you and I are going to put together

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is almost always going to look the same.

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Inside of every dockerfile,

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we're always going to specify a base image,

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and we'll talk about what that means in just a moment.

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It's going to be one of the first things we have to do.

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After that, we'll add in some additional configuration

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to run commands to add in some dependencies

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or some more software, some more programs that we need

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to successfully create and execute our container.

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And then finally we will specify a startup command

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for the image.

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So anytime we take that image

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and create a container out of it,

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it will be the command that is executed

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to essentially boot up or start the container.

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It's the same command that we've been talking about

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around all of these images all along.

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Okay, so that's it.

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That's all we have to do to make our own image,

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essentially just revolves around writing a dockerfile.

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So let's take a quick pause right here.

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We'll come back to the next section

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and get started working on our dockerfile.