Scheduling

Question 1

True or false?

Kubernetes adds a name in the nodeName section automatically in the spec defined when creatin the yaml file in a declarative way.

Answer 1

True

Question 2

True or false?

Kubernetes won’t allow you to change the nodeName after a pod has been created

Answer 2

True. the nodeName has to be set upon pod creation. It cannot be modified afterwards. In that case you would have to use a binding object.

Question 3

Lets say I have a pod and there’s no scheduler present, since I cannot assign a the pod to a node after the pod has been created, I would have to first delete the pod and afterwards, use the yaml file to create the pod again with the nodeName flag included, what single command can i use ton achieve these two steps?

Answer 3

kubectl replace –force -f your_yaml_filename.yaml

Question 4

The command generally used to check the status of a pod is kubectl get po, however, what if I don’t want to run this same command over and over again to check the status of it?

Answer 4

kubectl get po –watch

Question 5

What command can I use to check the node in which the port is running?

Answer 5

kubectl get po -o wide

Question 6

_______are key/value pairs that are attached to objects such as Pods.

Answer 6

Labels

Question 7

Via a label ___________, the client/user can identify a set of objects. The label _________is the core grouping primitive in Kubernetes.

Answer 7

selector

Question 8

how can I use a selector in Kubernetes?

Answer 8

kubectl get pods –selector app=App1

Question 9

what command can I use to get the number of pods?

Answer 9

kubectl get pods –no-headers| wc -l

Question 10

command to list all objects in a namespace:

Answer 10

kubectl get all –no-headers | wc-l

Question 11

true or false:
taints are placed on nodes and tolerations are places on pods.

Answer 11

True

Question 12

What are the main taint effects?

Answer 12

No schedule, PreferNoSchedule, NoExecute

Question 13

The _______ node has all the capability of hosting pods and running all management software. The ________ does not schedule pods on the master node.

Answer 13

master node
Scheduler (upon cluster setup, a taint is setup on the master node automatically that prevents any pods to be scheduled on the master node).

Question 14

What command can I use to see the master node taint created automatically?

Answer 14

kubectl describe node kubemaster | grep Taint

Question 15

How to label a node imperatively?

Answer 15

kubectl label nodes <node-name> <label-key>=<label-value></label-value></label-key></node-name>

Question 16

Whats is the objective of node affinity?

Answer 16

Is to ensure that pods are hosted on particular nodes.

Question 16

What is node selector?

Answer 16

is a simple way to specify which nodes a pod should be scheduled onto based on a set of label key-value pairs.

Question 17

Node _________is limited to looking for exact label key-value pair matches, meaning that it cannot use logical operators or more complex matching rules.

Answer 17

Selector

Question 18

Node __________ enables a conditional approach with logical operators in the matching process.

Answer 18

affinity

Question 19

Node Affinity uses a combination of label selectors, operators, and values to match nodes. The operators include:

Answer 19

• In
• NotIn
• Exists
• DoesNotExist

Question 20

Whats are the node affinity types - in available?

Answer 20

requiredDuringSchedulingIgnoredDuringExecution

preferredDuringSchedulingIgnoredDuringExecution

Question 21

What does preferredDuringSchedulingIgnoredDuringExecution mean?

Answer 21

• The scheduler will attempt to schedule the pod on a node that matches one of the rules.
• If no nodes match any of the rules, the pod may be scheduled on any node.

Question 22

What does requiredDuringSchedulingIgnoredDuringExecutionmean?

Answer 22

• Ensure that the pod is only scheduled on nodes that match the specified node selector rules.
• If no nodes match the node selector rules, the pod remains unscheduled.

Question 23

What is the planned node afiinity type?

Answer 23

requiredDuringSchedulingRequiredDuringExecution

Question 24

Node affnity support the following operators:

Answer 24

In NotIn Exists DoesNotExist Gt Lt

Question 25

What is the LimitRange in Kubernetes?

Question 26

How does Kubernetes define "Limits"?

Answer 26

the maximum amount of a resource to be used by a container.

Question 27

__________ are the minimum guaranteed amount of a resource that is reserved for a container.

Answer 27

Requests

Question 28

_______ is a compressible resource, meaning that it can be stretched in order to satisfy all the demand. In case that the processes request too much ______, some of them will be throttled.

Answer 28

CPU

Question 29

_________ is a non-compressible resource, meaning that it can’t be stretched in the same manner as CPU. If a process doesn’t get enough __________ to work, the process is killed.

Answer 29

Memory

Question 30

A _____________(and their analogues Kibibyte, Gibibyte,…) is 2 to the power of 20 bytes. It was created to avoid the confusion with the Kilo, Mega definitions of the metric system. You should be using this notation, as it’s the canonical definition for bytes, while Kilo and Mega are multiples of 1000. the _________________ is multiple of 1024.

Answer 30

Mebibyte

Question 31

True or false: The status OOMKilled indicates that it is failing because the pod ran out of memory. Identify the memory limit set on the POD.

Answer 31

true

Question 32

What does a DaemonSet in Kubernetes do?

Answer 32

ensures that all (or some) Nodes run a copy of a Pod. As nodes are added to the cluster, Pods are added to them. As nodes are removed from the cluster, those Pods are garbage collected. Deleting a DaemonSet will clean up the Pods it created

Question 33

True or false: you can create static pods by placing their definition files in the designated directory.

Answer 33

True (this only applies to pods as the kubelet can only interpret pods)

Question 34

____________ are a way to run pods directly through a Kubernetes node's kubelet daemon instead of through the API server.

Answer 34

Static Pods. This allows static pods to start up even if the API server is not running yet, which is useful for bootstrapping the Kubernetes control plane components like the API server, controller manager, and scheduler.

Question 35

True or false: regular API-server created pods do not have acces to the kubelet filesystem.

Answer 35

True, this is why Static pods can also be useful for running privileged pods that need access to the kubelet filesystem.

Question 36

Why are static pods in kubernetes marked as controlplane?

Answer 36

Static pods in Kubernetes are marked as "controlplane" because they are typically used to run the Kubernetes control plane components (like the API server and controller-manager) directly on a node, managed by the kubelet rather than the API server, which is the primary way pods are managed.