WEBVTT

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Let's go over the practice test
for our multiple schedulers.

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What is the name of the pod that deploys

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the default Kubernetes scheduler
in this environment?

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Let's do a kubectl get pods command

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in the kube system namespace.

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We're going to look here.

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We see the pod
is kube-scheduler-controlplane.

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Let's select that.

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What is the image used
to deploy the Kubernetes scheduler?

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Inspect the kube scheduler pod
and identify the image.

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Let's do a kubectl
describe pod scheduler

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and then specify
the namespace as kube system.

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Here we have the image and that is

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k8s.gcr.io/kubescheduler:

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version 1.23.0, as of this recording.

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I'm going to select that.

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Now, we've already created
the ServiceAccount and ClusterRoleBinding

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that our custom scheduler
will make use of.

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All of these are already created.

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If you like to take a look,

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you can do a kubectl
get service account my-scheduler.

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We see that my-scheduler service
account in the kube system namespace.

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Similarly, there are cluster
role bindings as well.

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That's already done for us,

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so we don't have to worry about that.
Let's go forward.

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Let's create a ConfigMap that
the new scheduler will employ

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using the concept
of ConfigMap as a volume.

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We have to create a ConfigMap with
the name using the contents of the file.

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There's already a file here,
and this is a configuration

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that will be passed
through to the new scheduler

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that we're going to create.

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The file is there, we just have
to create a ConfigMap for it.

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We'll do a kubectl create configmap.

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The name will be--

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let's copy and paste.

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It has to be created from file.

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We use the form file
as the path to the file

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and also specify the name system.

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This may be kube system.

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There is no name.

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Let's verify that it's created.

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It's in the kube system namespace.

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That's created.

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Click Next.

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I deploy an additional
scheduler to the cluster

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following the given specification

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used to manifest file provided
at root my-scheduler.

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There's already a file given for us

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that's at root my-scheduler.yaml

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or just since we're already
in that directory,

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you could just give the file name.

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We see that most of the work
is already done, the liveness probe,

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the readiness probes are all set,

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so we don't really have
to worry about that.

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All we need to do is add
this image that's given here,

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and we have to use the same image
that's used by the current scheduler.

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Let's find that out first.

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Let's do a kubectl get pods -a.

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This is current scheduler.

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Let's do a describe

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and the system and the script
for the image.

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Let's get this image ID, and we're
going to put that in the file

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instead of this placeholder here.

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If you look at the rest of the file,

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it already has
the ConfigMap that we created.

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If you scroll down, you'll see
there is the ConfigMap that we created.

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That's already configured,
and that basically passes

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through as a volume mount here.

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We'll talk about ConfigMaps
in the upcoming lectures

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if you haven't already
gone through that yet.

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We're going to create this.

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Let's verify that it's created,

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the kube-system namespace.

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We have my-scheduler here.

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Let's check.

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That's done.

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The final step is to create a pod.

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There's already a pod
definition file given

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and use it to create a pod
with a new custom scheduler.

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Here we have
the nginx pod definition file.

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This is pretty straightforward.

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Just nginx pod with the nginx image.

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What we need to do
is specify the custom scheduler

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which is basically
my-scheduler given here.

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As we learned in the lecture,

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you have to add a new field here

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called schedulerName,

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and then we specify the name
of the scheduler we just created.

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Save that, and then we create a pod

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and we make sure pod is running.

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That's it.

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That's the end of this lab.