WEBVTT

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-: When we first started talking about pods and deployments

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about a dozen videos or so ago,

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you might recall that I opened up my terminal

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at some point in time and I told you

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that I was going to run a series of commands,

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and I also told you, don't try to run these commands.

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I told you don't run these because you're probably

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gonna see an error message or something like that.

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And so one of the commands that I ran

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at that point in time, was a simple Docker P S.

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Remember the Docker PS commands will print out the status

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of all the different containers that are running

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on your local machine.

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So you saw me run this command, and when I did so

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there appeared to be a tremendous number

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of containers running on my local machine.

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Now, if you open up your terminal right now

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and you run a docker PS as well,

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you're probably only gonna see like maybe zero,

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one, two or three local containers.

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And chances are there are they're going to be containers

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that we had started up in previous sections

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that you never cleaned up or anything like that.

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So why am I seeing this output right here

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of all these different containers?

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And if you look at the name of them

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they all appear to be very clearly related to Kubernetes.

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So why am I seeing all this output right here

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and why are you only seeing one or two or three?

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Well, in this section we're going to

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investigate this a little bit.

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We're going to get a better idea

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of what docker is doing for us both on our local computer

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and inside that virtual machine that forms our node,

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we're going to get a better idea

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of how we can kind of reach into the node

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and play around with a copy of docker inside there.

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All right, so first off, couple diagrams.

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Now we've looked at some variations

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on this diagram right here a couple time,

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and we've gone over the process of what happens

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when we feed in a config file through kubectl

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a couple times as well.

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But I wanna give you just one more quick reminder

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of what's going on.

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So remember we take a configuration file

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that wants to create either a pod or a deployment.

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We feed that into kubectl,

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that gets passed off to the master,

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and then the master reaches into the virtual machine

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and communicates with the copy of docker

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that runs only inside of the virtual machine,

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and it tells it, hey docker client

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we need to create a new container.

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Go off and grab this image and create a container out of it.

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The docker client then turns around

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and says to the docker server, hey docker server

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we need to go and grab an image

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and we need to create a container out of it.

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And so it's then up to the docker server

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to reach out to docker hub, download an image,

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store it inside of some local cash,

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and then build a container out of it.

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Again, we've gone over this flow several times,

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now something else that we've discussed a couple times

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is the fact that we have two copies of docker

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running on your local machine right now.

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We have the copy of docker that's running inside

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of the virtual machine, and we have the copy of docker

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that we installed way back at the start of this course,

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when we ran docker for Mac or docker for Windows.

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That's the copy of docker that's associated

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with this status bar drop down right here.

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All right, now I wanna show you

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something really interesting, all right,

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I'm gonna flip back over to my terminal

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and inside of this terminal window right here

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I'm going to run docker PS again.

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When I run that, you're gonna see, yep

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I've got all this output from docker right here.

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Now I'm gonna open up another terminal window,

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so here's just another simple terminal window over here

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and I'm going to do a docker PS over here as well.

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And when I do it over here, it appears that

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I'm running absolutely no containers whatsoever.

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So what's going on here?

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Well, essentially I have configured docker

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inside of these two terminal windows to connect

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to one of these different docker servers

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that's running on my local computer.

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So whenever I type in a command inside my terminal,

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I'm accessing the copy of docker client

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that was set up with docker for Mac,

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when I installed it way earlier inside this course.

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My first terminal window over here,

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this one where I run docker PS

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and I see no running containers whatsoever.

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This copy of the docker client

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or the docker CLI,

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is connecting to the docker server

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that is running on my local computer,

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and again, this is the copy of Docker server

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that was installed with Docker for Mac.

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In the second terminal window,

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I bet you can guess what's going on

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in the second terminal window over here,

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I have configured my local copy of Docker client,

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not to connect to my local Docker server.

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Instead, I have reconfigured it to talk to the copy

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of Docker server running inside of the virtual machine.

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So, inside of this very specific terminal window right here

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when I do a docker PS, my copy of Docker client,

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the Docker CLI is reaching into the virtual machine.

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It's getting in contact with a copy of Docker server

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inside there, and it's asking it,

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hey what different containers are you running?

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And so that's why inside of this terminal window right here

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I see this big list of Kubernetes related containers

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including the multi-client container right here.

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And again, all these containers are running

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inside of my virtual machine.

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All right, so again the idea here

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all I want you to understand right now

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is that I have one copy of Docker client

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and between these two terminal windows, I have configured it

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to either talk to my local copy of Docker server

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or the copy of Docker server that is running inside

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of the virtual machine.

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So let's take a quick pause right here,

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now that we understand that,

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when we come back the next section

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I'm gonna show you how you can reconfigure

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your local copy of Docker client

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to talk to Docker server inside the virtual machine.

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And of course, I'll also tell you

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why we would want to do this at all.

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All right, so quick break

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and we'll come back in the next section.