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In the last section we went over the behind the scenes flow of what occurred during that darker build

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process.

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Now there's a rather long section and we went through a lot of detail.

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So in this section I want to do a quick recap just a very quick overview on the really important critical

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flow to understand.

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Now if you don't want to hear me lecture about this stuff anymore.

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If you feel like you already have a good understanding.

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No problem.

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Positivity right now and move on to the next section.

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Again we're only going to do a recap of what we just spoke about a moment ago.

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OK.

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So here's the recap with a slightly different diagram.

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So everything started with the firm Alpine instruction that told the Dockers server or Dr. Damon to

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go and download the Alpine image and we use the Alpine image as a base because it comes pre installed

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with some really handy programs that are useful for us creating our image.

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The next thing that occurred was the run instruction was executed by the docker server.

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The first thing that occurred there was it looked for the image from the previous step.

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And so it went back to the previous step and got the Alpine image that had just been downloaded that

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image was then used to create a brand new very temporary container.

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So here's our container over here and then the command that we had specified.

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So AP okay add dash Update Read This was executed inside of that temporary container.

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The AP program was executed it downloaded and installed red is inside the file system of that container.

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So the result is a container with a modified file system.

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It now has red is added onto it.

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We then took a snapshot of that containers new file system.

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And the result was a file system snapshot.

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We then shut down the temporary container like this one right here that had just been created and we

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got our image ready for the next instruction.

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And the image that we're using is that file system snapshot.

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The modified one that we just created when we installed reds so you can now imagine that we are now

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passing onto the next step.

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We are essentially passing along the Alpine image but with red is added on top so we then move on to

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the command read a server instruction.

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We again get the image from the previous step.

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We again create a temporary container out of it.

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But this time around rather than executing a command inside there which is the purpose of the run instruction

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we instead use the CMT instruction which is used to specify what the container should do or mean what

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the image should do when it is started up as a container.

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So we told the temporary container that we just created that whenever it gets started in the future

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it should try to execute the command this dash server.

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And the result was a container that has a modified primary command.

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We then shut down that temporary container and we got it ready where you took an image out of it and

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got it ready for the next instruction.

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But in that case there are no more instructions no more steps to execute inside this file.

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And so the output of the overall series of steps is whatever image was generated during the last instruction

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inside of our darker file.

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All right.

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So like I said just a quick recap on that entire process one more time because it is it's not super

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critical that you have an in-depth understanding here but it definitely makes a lot of this darker stuff

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a lot easier if you have a good grasp on this entire flow.

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So let's take a quick pause right here and we'll continue in the next section.