WEBVTT

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In this video, we're going to walk over

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the solution for the lab on services.

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The first question is,

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how many services exist on the system?

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We're going to run
the kubectl get service command,

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or you can also run
the kubectl get svc command.

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It's a short for service.

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We can see that there's just one service.

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Select that.

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This is a default service
created by Kubernetes.

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What is the type
of the default Kubernetes service?

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If you look at the type here,
we see that it's cluster IP,

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so let's select cluster IP.

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We'll look at what this service is,
in particular, later when we talk about

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the Kubernetes architecture,
the API server in more detail.

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For now, let's just consider it
as any other service.

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What is the targetPort configured
on the Kubernetes service?

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For this, you've got to look
at the service in more detail.

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We're going to do
a kubectl describe command,

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and we're going to describe
the service named Kubernetes.

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Here, we see the port details.

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The port is 443.

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The targetPort is 6443.

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The question is, what is a targetPort,
so we'll select 6443.

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How many labels are configured
on the Kubernetes service?

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If you look at this right here,
so there are two labels.

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Component is API server
and the provider is Kubernetes.

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This service is basically
the Kubernetes API server.

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We'll discuss more about the API server

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and the service specifically when
we learn about the API server in detail,

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and the CK, of course,
when we get to that.

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For now, the answer is two.

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The next question is,

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how many endpoints are attached
on the Kubernetes service?

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For now, we have no idea
what the service is

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since the service was already created.

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We don't really know what it is.

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We're exploring
and finding out more about it.

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One thing if we want
to look at right here and understand

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is how many pods
is the service directing traffic to?

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That's what you can see here
in the endpoints section here.

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Endpoints, it says,
there's one IP end port

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so that's one endpoint.

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If there are multiple ports
that the services directing traffic to,

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then there would be multiple ports here.

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Let me quickly explain what endpoints are

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because we have not
really discussed about endpoints.

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Here we have a service

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and three ports.

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What we do usually is
when we create a port,

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we know that it has a label to it.

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Let's say, for example, it's set to app

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and FE for frontend or something.

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The way that we create a service
in order to direct traffic to these ports

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is we provide the same labels

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as selectors to the service.

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What the service does is it identifies
all the ports with the same label

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and then directs traffic to those ports.

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Once it identifies
the port with the labels

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that's when the service
has these endpoints.

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From the perspective of a service,
endpoints are basically these,

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the ports,
the ports that the service has identified

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that is going to direct traffic to

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based on the selector
specified on the service

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and the labels on the ports.

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Now, when we create
a service for a set of ports,

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now, we might think that

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depending on the label
and the selector we specified,

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the service is going
to direct traffic to those ports,

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but it might be possible
that we have another port

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which we accidentally created
with the same kind of label.

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The service is then going
to direct traffic to that port as well.

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That's when when we look at the output
of the kubectl describe command

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that we can identify
the additional endpoints

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apart from what we thought
we had configured.

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When look at the kubectl
described command for the service,

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we're going to see
that there are four endpoints.

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In fact, our application

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had a replica set
perhaps that just had three endpoints

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that are three ports.

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That's where the endpoint can help.

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Just to just to give you a bit context,
let's say we create--

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We have a single pod,
and we create a service.

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We set a label to FE,

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but we accidentally
set the selector to say FR,

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something that's different.

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Then when we try to access the service,

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we're not able
to get through to the application.

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That's when you look
at the description of the service

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and you realize
that the endpoints are zero.

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That means the service
has not identified any ports.

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Then that's when we can look
at the labels and selectors

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in more detail to identify the root cause.

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That's what endpoints are.

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It's a specification of all the ports

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that that particular service
has identified

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based on the selectors
and the labels set on those ports.

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In this case,

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this particular run service
has just one endpoint.

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We're going to select one here.

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The next question is how many deployments
exist on the system now

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in the current(default) namespace?

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Let's identify deploy.

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There's just one deployment,
so we're going to select one.

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The next question is,

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what is the image used
to create the pods in the deployment?

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We're going to look

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at the deployment in a bit more detail.

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We see the image is
kodekloud/simple-webapp:red.

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That's this one.

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Are you able to access the Web App UI?

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Try accessing the Web Application UI
using the tab at the top.

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There's the link here and click on it,

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we see that it gives us
a bad gateway error.

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The answer is no,
we're not able to access the web app UI.

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That's really because there's no service.

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We have to create a new service
to access the web application

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using the service-definition-1.yaml file.

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There is a service
definition-1.yaml file here.

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We look at it.

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This is, basically,
a kind of file with the basic framework

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to create a service.

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We will use that

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and update the details
that are given here.

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We're going to give it a name.

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Set the NodePort
and all the different ports,

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and also specify the selector.

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Now, if you're not sure
about getting this framework,

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you could go
to the Kubernetes documentation pages,

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search for service, and select service.

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Here, you get a sample
that you can then copy and use.

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We will talk about
imperative ways or commands

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to create service
in the upcoming lectures.

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For now, let's just go with this.

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The name is web app-service.

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Type is NodePort.

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TargetPort is 8080.

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Port is 8080,

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nodePort is 30080,

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and the selector name is simple-webapp.

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Let's create that service.

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That's done.

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Let's check.

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Let's try to access this now.

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That's working.

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As I said, in the upcoming lectures,

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there is a section where
we talk about imperative commands,

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and we'll discuss
how we can create a service.

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There are different ways
of creating a service

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and we'll discuss that when we get there.

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For now, that's the end of this lab.