Linux Foundation CKA Quiz 5 Topic 5 Questions 21-25

Question: 1

List ''nginx-dev'' and ''nginx-prod'' pod and delete those pods

Akubect1 get pods -o wide
kubectl delete po ''nginx-dev''
kubectl delete po ''nginx-prod''

Bkubect1 get pods -o wide
kubectl delete po ''nginx- prod''
kubectl delete po ''nginx-prod''

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Question: 2

SIMULATION

The following TLS certificates/key are supplied for connecting to the server with etcdctl:

* CA certificate: /opt/KUCM00302/ca.crt

* Client certificate: /opt/KUCM00302/etcd-client.crt

* Client key: Topt/KUCM00302/etcd-client.key

Asolution

Bsolution

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Question: 3

SIMULATION

Create a persistent volume with name app-data, of capacity 2Gi and access mode ReadWriteMany. The type of volume is hostPath and its location is /srv/app-data.

APersistent Volume
A persistent volume is a piece of storage in a Kubernetes cluster. PersistentVolumes are a cluster-level resource like nodes, which don't belong to any namespace. It is provisioned by the administrator and has a particular file size. This way, a developer deploying their app on Kubernetes need not know the underlying infrastructure. When the developer needs a certain amount of persistent storage for their application, the system administrator configures the cluster so that they consume the PersistentVolume provisioned in an easy way.
Creating Persistent Volume
kind: PersistentVolume
apiVersion: v1
metadata:
name:app-data
spec:
capacity: # defines the capacity of PV we are creating
storage: 2Gi #the amount of storage we are tying to claim
accessModes: # defines the rights of the volume we are creating
- ReadWriteMany
hostPath:
path: '/srv/app-data' # path to which we are creating the volume
Challenge
Create a Persistent Volume named app-data, with access mode ReadWriteMany, storage classname shared, 2Gi of storage capacity and the host path /srv/app-data.

2. Save the file and create the persistent volume.

3. View the persistent volume.

* Our persistent volume status is available meaning it is available and it has not been mounted yet. This status will change when we mount the persistentVolume to a persistentVolumeClaim.
PersistentVolumeClaim
In a real ecosystem, a system admin will create the PersistentVolume then a developer will create a PersistentVolumeClaim which will be referenced in a pod. A PersistentVolumeClaim is created by specifying the minimum size and the access mode they require from the persistentVolume.
Challenge
* Create a Persistent Volume Claim that requests the Persistent Volume we had created above. The claim should request 2Gi. Ensure that the Persistent Volume Claim has the same storageClassName as the persistentVolume you had previously created.kind: PersistentVolume
apiVersion: v1
metadata:
name:app-data
spec:
accessModes:
- ReadWriteMany
resources:
requests:
storage: 2Gi
storageClassName: shared
2. Save and create the pvc
njerry191@cloudshell:~ (extreme-clone-2654111)$ kubect1 create -f app-data.yaml
persistentvolumeclaim/app-data created
3. View the pvc

4. Let's see what has changed in the pv we had initially created.

Our status has now changed from available to bound.
5. Create a new pod named myapp with image nginx that will be used to Mount the Persistent Volume Claim with the path /var/app/config.
Mounting a Claim
apiVersion: v1
kind: Pod
metadata:
creationTimestamp: null
name: app-data
spec:
volumes:
- name:congigpvc
persistenVolumeClaim:
claimName: app-data
containers:
- image: nginx
name: app
volumeMounts:
- mountPath: '/srv/app-data '
name: configpvc

BPersistent Volume
A persistent volume is a piece of storage in a Kubernetes cluster. PersistentVolumes are a cluster-level resource like nodes, which don't belong to any namespace. It is provisioned by the administrator and has a particular file size. This way, a developer deploying their app on Kubernetes need not know the underlying infrastructure. When the developer needs a certain amount of persistent storage for their application, the system administrator configures the cluster so that they consume the PersistentVolume provisioned in an easy way.
Creating Persistent Volume
kind: PersistentVolume
apiVersion: v1
metadata:
name:app-data
spec:
capacity: # defines the capacity of PV we are creating
storage: 2Gi #the amount of storage we are tying to claim
accessModes: # defines the rights of the volume we are creating
- ReadWriteMany
hostPath:
path: '/srv/app-data' # path to which we are creating the volume
Challenge
Create a Persistent Volume named app-data, with access mode ReadWriteMany, storage classname shared, 2Gi of storage capacity and the host path /srv/app-data.

2. Save the file and create the persistent volume.

3. View the persistent volume.

* Our persistent volume status is available meaning it is available and it has not been mounted yet. This status will change when we mount the persistentVolume to a persistentVolumeClaim.
PersistentVolumeClaim
In a real ecosystem, a system admin will create the PersistentVolume then a developer will create a PersistentVolumeClaim which will be referenced in a pod. A PersistentVolumeClaim is created by specifying the minimum size and the access mode they require from the persistentVolume.
Challenge
* Create a Persistent Volume Claim that requests the Persistent Volume we had created above. The claim should request 2Gi. Ensure that the Persistent Volume Claim has the same storageClassName as the persistentVolume you had previously created.kind: PersistentVolume
apiVersion: v1
metadata:
name:app-data
spec:
accessModes:
- ReadWriteMany
resources:
requests:
storage: 2Gi
storageClassName: shared
2. Save and create the pvc
njerry191@cloudshell:~ (extreme-clone-2654111)$ kubect1 create -f app-data.yaml
persistentvolumeclaim/app-data created
3. View the pvc

4. Let's see what has changed in the pv we had initially created.

Our status has now changed from available to bound.
5. Create a new pod named myapp with image nginx that will be used to Mount the Persistent Volume Claim with the path /var/app/config.

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Question: 4

SIMULATION

For this item, you will have to ssh to the nodes ik8s-master-0 and ik8s-node-0 and complete all tasks on these nodes. Ensure that you return to the base node (hostname: node-1) when you have completed this item.

Context

As an administrator of a small development team, you have been asked to set up a Kubernetes cluster to test the viability of a new application.

Task

You must use kubeadm to perform this task. Any kubeadm invocations will require the use of the --ignore-preflight-errors=all option.

* Configure the node ik8s-master-O as a master node. .

* Join the node ik8s-node-o to the cluster.

Asolution
You must use the kubeadm configuration file located at /etc/kubeadm.conf when initializing
your cluster.
You may use any CNI plugin to complete this task, but if you don't have your favourite CNI plugin's manifest URL at hand, Calico is one popular option: https://docs.projectcalico.org/v3.14/manifests/calico.yaml
Docker is already installed on both nodes and apt has been configured so that you can install the required tools.

Bsolution
You must use the kubeadm configuration file located at /etc/kubeadm.conf when initializing
your cluster.
You may use any CNI plugin to complete this task, but if you don't have your favourite CNI plugin's manifest URL at hand, Calico is one popular option:

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Question: 5

SIMULATION

Given a partially-functioning Kubernetes cluster, identify symptoms of failure on the cluster.

Determine the node, the failing service, and take actions to bring up the failed service and restore the health of the cluster. Ensure that any changes are made permanently.

You can ssh to the relevant I nodes (bk8s-master-0 or bk8s-node-0) using:

[student@node-1] $ ssh <nodename>

You can assume elevated privileges on any node in the cluster with the following command:

[student@nodename] $ | sudo --i

Asolution

Bsolution

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Linux Foundation CKA Quiz:5 Topic:5 Questions:21-25