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We just spoke about the four different types of services.

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We're not going to try to create our own service.

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We're going to first focus on creating a node port.

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Remember in the last video I said that we're not going to use a node port very often unless we are doing

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it for just development purposes.

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So why are we making a node port first if it's not what we're going to use very often.

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Well it's really simple a cluster IP is used to network different pods together.

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Right now we have only one odd.

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So if we start to create a cluster IP service.

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Well it's not really gonna do anything because we're not really exposing our pod to any other pods.

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We don't have any other pods.

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Why are we not creating a load balancer a load balancer usually requires a decent amount of additional

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configuration.

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So right now the easiest service to create and the one that actually does something for right now we're

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actually has some effect on our cluster is a node port.

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That's why we're gonna create that first.

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Now all these different services are types of objects.

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Remember a deployment a pod a service.

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These are all referred to as objects and Cuban eddies all objects we creates are made by first creating

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a config file and then applying that config file to our cluster.

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So whenever we talk about creating a service or modifying a service we are always talking about creating

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a config file.

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So let's get to it back inside my editor.

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I'm going to find that key aides directory and inside there I'll make a new file I'll post dash s r

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v dot yellow SRB stands for service inside of here we're going to write out some config that looks very

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similar to the config we wrote inside that deployment file and the pod file previously.

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So we will first begin with an API version of the one a kind of service a metadata that has name of

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posts dash SRB the name right here is going to be the name of the service.

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So if we ever try to print out all the services that are running inside of our cluster we will see post

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dash as Harvey will then define our spec which is going to customize how this service actually behaves.

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The first thing we'll do is designate a type of node port as you guess that's going to be the type of

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service that we are trying to create.

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We are trying to make a node port service after that.

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We're going to put down a selector with an app of posts like so.

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So what is this selector thing all about.

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Well remember the entire goal of a node Port is to expose a set of pods to the outside world.

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This service right here this node port service needs to know about what pause it should actually expose.

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And that's the goal of that selector thing.

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Remember a selector right here of outposts.

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We did something very similar to this back inside of our deployment file.

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So let's go back over to deployment very quickly.

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So inside of here we have that template section and the template is describing how all these different

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pods should be created by the deployment inside the templates.

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We had a metadata with the labels of app posts.

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So this label right here is applying a label or some kind of designation of sorts an identifier of sorts

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to the pod that is going to be created.

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So by writing a selector of app post right here we are telling the service to try to find all the different

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pods with a label of app posts and expose traffic or expose those pods to the outside world this whole

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label system in general.

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You can really think of this as being very similar to class names that get applied to an HMO element

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in the browser.

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So if you're familiar with HDL Well we apply class names to elements so we can select a broad range

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or a set of elements very easily.

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You should really think of this entire label and selector system as being very similar in nature.

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Next up we're going to designate some ports.

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So this port section is going to list out all the different ports that we want to expose on the target

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pod.

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Well let me give you a quick reminder on the Postal Service really quickly or a postal application inside

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of our postal application directory.

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I can open up the index dot J.S. file at the very bottom.

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You'll recall that we had said app listen on port four thousand right there.

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So our application nation is listening for traffic on port four thousand inside of our service.

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We need to make sure that we specifically expose port 4000 on our part.

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So that's what this ports section is all about.

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We're going to list out all the different ports that we want to expose on the part now sports is going

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to be an array of entries.

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And remember we set up a rate entry in Yemen by putting in that little dash right there.

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We'll say dash then name of those a protocol of DCP a port of 4000 and a target port of 4000.

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I got some bad news.

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These port properties right here are pretty darn confusing.

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I'm not going to lie with you.

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So what are these all about.

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Well again if we think about our post application it is listening for traffic on port four thousand.

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So this 4000 right here is essentially saying we want to open up access on Port 4000.

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But real quick question why are we listening this out twice.

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What is the difference between Port and target ports.

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Let me show you a diagram.

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I'm going to tell you right away.

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This diagram is probably going to make things a little bit more confusing so bear with me for just a

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second.

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All right.

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Here's our diagram on the right hand side is our node.

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Remember the node is the actual kind of virtual machine that is running all of our Cuban eddies objects

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on the left hand side is our browser on the far right hand side is the actual pod that is running our

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post container.

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Now on that container we've got some application that is listening for traffic on port four thousand.

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We refer to that ports that is attach the container.

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So the ultimate port that we want to direct traffic to as the target port so target port.

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Back over here.

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This is the actual port that our application is listening for traffic on.

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That's where we ultimately want to send traffic to.

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We are creating a node port service the node port service is going to have a port of its own.

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So that is referred to as simply the port.

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And that is what this property is right here so we are sending traffic to port 4000 on a node port service

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and that service internally is going to redirect that traffic over to Port 4000 on the container itself

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the port and the target port do not have to be identical.

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So this could be 5000 right here.

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And if we make a request to work 5000 on the no port service the service will redirect that traffic

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to port 4000.

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On the container.

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Now are there scenarios in which we would want to have a different port in a different target port.

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Maybe I'm kind of hard pressed to think of one off the top of my head.

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So usually Bassim during the time you're going to have a port and a target port that are just identical.

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That's the long and short of it.

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So at the end the day this whole section right here you can pretty much copy paste between all your

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different services that you are creating and just change that actual number to be whatever your actual

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application is listening for traffic on.

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So for example if we were creating a service where our comments application.

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No comments right here.

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If we open up that index not just file that application is listening for traffic on four thousand one.

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So if we were creating a service for comments we would pretty much copy paste the same thing right here

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and just change that to four thousand one the name on here of posts is really just for logging purposes

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and having some name attached to it.

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The name can be anything you want it to be.

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So we could change that to whatever no big difference.

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Well usually just name it after the service.

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No big difference OK.

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So that is our service has been completed.

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Now you might notice back on Instagram over here I had this additional port right here.

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We'll talk about that in just a moment.

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This video is running a little bit long.

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So let's take a quick pause right here and we're going to apply this config file to our cluster in just

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a moment to actually create the service.