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Throughout this course we've been making use of images that have been created by other engineers.

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So for example we have used say the hello world image or reduced or busy box.

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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 and then created a container out of them.

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At this point we're going to start to figure out how we can build our own custom images so that we can

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run our own applications inside of our own personalized containers.

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The process for making an image is somewhat straightforward like all things you just have to learn a

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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 going to create something called a docker file a darker file is essentially a plain text file

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that is going to have a couple of lines of configuration placed inside of it.

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This configuration is going to define how our container behaves or more specifically what different

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programs it's going to contain and what it does when it starts up as a container.

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Once we create that Docker file will then pass it off to the docker client which you'll recall is the

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docker supply that we've been using at our terminal in turn.

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The Docker client will provide the file 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 good to take the docker file look at all the lines of configuration that we have inside of it and

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

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Now that Docker file is where all the complexity is going to sit and like I just said a moment ago it's

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not really going to be the worst thing in the world.

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It's just about learning a couple of new commands that's all in fact just about every Docker file that

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you and I are going to put together is almost always going to look the same inside of every Docker file.

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We're always going to specify a base image.

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

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It's got it.

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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 to run commands to add in some dependencies or

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some more software some more programs that we need to successfully create and execute our container.

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And then finally we will specify a start up command for the image.

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So anytime we take that image and create a container out of it it will be the command that is executed

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to essentially boot up or start the container is the same command that we've been talking about around

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all of these images all along.

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OK.

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So that's it.

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That's all we have to do to make our own image essentially just revolves around writing a docker file.

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So let's take a quick pause right here.

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We'll come back the next section and get started working on our Docker file.