WEBVTT

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Okay, so let's go over the lab
for practicing taints and tolerations.

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Let's start with the first question.

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How many nodes exist on the system,
including the control plane?

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Let's look at the number of nodes

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and we see that there are 2 nodes
control plane and node01,

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the answer is 2.

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The next question is,
do any taints exist on node01 node?

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For that, we're going to have
to take a closer look at node01.

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We do kubectl describe node01

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and we see

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taints right here

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and we see that there are none.

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There are no taints
on this particular node.

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I'm going to select, no.

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It's going to clear my screen.

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The next question is
to create a taint on node01

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with key of spray value of mortein
and effect of NoSchedule.

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We're going to continue
with the silly example

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that we used in the lecture

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of the spray and mortein
and mosquito and B.

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Here, the task is to create a taint.

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We're going to do kubectl taint,

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and let's quickly look at the help.

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The command is kubectl taint
and then nodes,

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then the name of the node,

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and then followed by these values,
which are the key has to be spray.

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Then the value is mortein
and then the effect is NoSchedule.

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Let's do that.

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It's kubectl taint node.

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It's node01.

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Then the key is spray

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and the value is mortein

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and the effect is NoSchedule.

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Okay.

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Let's confirm that.

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We have the spray=mortein
and NoSchedule effect,

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so that's done.

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We now have a taint on node01.

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Now the goal is to create a new pod
with the nginx image

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and the pod name as mosquito.

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We're going to do a kubectl run,

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that's the pod name image=nginx.

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Let's do get pods.

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Let me see that it's created,
ignore the status for now.

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Okay, so what is
the state of the pod?

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It seems to be in a pending state.

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Select pending.

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Now, why do you think
the pod is in a pending state?

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Is it because the image
is not available, is there an error?

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Let's see.

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Let's do describe pod

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and the pod name

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and here, you'll see

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the reason why
it's in a pending state.

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It says that
the pod didn't tolerate 1 node

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that had taint, spray, and mortein
that the pod didn't tolerate.

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Basically, the pod mosquito
cannot tolerate the taint mortein,

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that's a problem here.

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We're going to select that.

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Okay, so now we have to create
another pod named bee

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with the nginx image,

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which has a toleration
set to the taint mortein.

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We're going to do a kubectl
run command to create a pod.

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The name is going to be bee

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and the image is going to be nginx.

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Basically, now we have to add
toleration to it,

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but you cannot specify toleration
in the command line.

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What we're going to do is
we are going to do a dry run= client

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to generate a yaml file
with this pod.

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That's the yaml file,

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and we're going to redirect that
to bee.yaml.

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We have this in bee.yaml,
we're going to edit bee.yaml file,

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and we're going to add in tolerations.

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Add a section called tolerations.

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Now if you're not sure of the format,

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check out the Kubernetes
documentation pages

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and search for taints
and tolerations.

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That's the first result.

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This is the command taint

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and this is the format
for tolerations

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so dash key, operator,
value, and effect.

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That's key,
so key is going to be spray,

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operator, value, and effect.

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The value is going to be mortein,

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effect is going to be NoSchedule.

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Finally, we have operator
which has to be equal.

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Operator set to equal,

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you save that,

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and let's create image.

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Okay, it's now
in a container-creating state.

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Let's watch the creation process

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and we can see that
it's now in a running state.

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This part is now running.

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Okay, so that's correct.

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Notice the bee pod
was scheduled on node01.

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Let's see where it was scheduled.

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We see the bee pod is on node01.

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Basically, now this bee was able
to tolerate the taint set on node01.

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Do you see any taints
on controlplane node?

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Let's look at the controlplane node.

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Let's look at taints

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and we see that yes, there is a taint
set on the controlplane node

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and it's set to NoSchedule.

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That's the effect.

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Yes, it's set
and it's set to NoSchedule.

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Okay, now remove the taint
on controlplane,

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which currently has
the taint effect of NoSchedule.

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We've got to remove that.

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First, let's get that.

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This is the taint.

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Let's copy that.

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The command to remove
is the same, kubectl taint.

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You just specify the node,
that's controlplane node.

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Specify the taint
that we want to remove

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and at the end,
you've got to put a dash or a minus

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or to remove that taint.

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It says it's untainted.

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Let's confirm that.

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Go back to taint.

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I see that nothing is set.

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Let's click on check.

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Okay, so that's done.

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Now we've got to check

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the status of the pods again.

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We see that the pod mosquito
which earlier was in a pending state

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is now in a running state.

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That's the state of the pod mosquito.

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Then we have to,

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let's check
on what node it is placed.

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As you can see, it's now placed
on the controlplane node.

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Earlier in the beginning,

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the controlplane node
has a taint set on it

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and then we set taint on node01.

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Then we created the mosquito pod.

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It was not placed on any of the nodes

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because both of them
had a taint then.

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Then we created the bee pod
with the toleration or node01

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so the bee pod
was able to be placed on node01.

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Then we removed
the taint on controlplane.

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Without doing anything
the pod mosquito

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was automatically placed
on controlplane

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because it no longer has
any taint on it.

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The answer to this is controlplane.

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Okay, so that's the end of this lab.