Lightning Lab 1

I am ready! Take me to Lightning Lab 1

Solution to LL-1

Upgrade the current version of kubernetes from 1.26.0 to 1.27.0 exactly using the kubeadm utility.

There is currently an issue with this lab which requires an extra step. This may be addressed in the near future.

On controlplane node

Drain node

kubectl drain controlplane --ignore-daemonsets

Upgrade kubeadm

apt-get update
apt-mark unhold kubeadm
apt-get install -y kubeadm=1.27.0-00

Plan and apply upgrade

kubeadm upgrade plan
kubeadm upgrade apply v1.27.0

Remove taint on controlplane node. This is the issue described above. As part of the upgrade specifically to 1.26, some taints are added to all controlplane nodes. This will prevent the gold-nginx pod from being rescheduled to the controlplane node later on.

kubectl describe node controlplane | grep -A 3 taint

Output:

Taints:   node-role.kubernetes.io/control-plane:NoSchedule
          node.kubernetes.io/unschedulable:NoSchedule

Let's remove them

kubectl taint node controlplane node-role.kubernetes.io/control-plane:NoSchedule-
kubectl taint node controlplane node.kubernetes.io/unschedulable:NoSchedule-

Upgrade the kubelet

apt-mark unhold kubelet
apt-get install -y kubelet=1.27.0-00
systemctl daemon-reload
systemctl restart kubelet

Reinstate controlplane node
```
kubectl uncordon controlplane
```

Upgrade kubectl

apt-mark unhold kubectl
apt-get install -y kubectl=1.27.0-00

Re-hold packages
```
apt-mark hold kubeadm kubelet kubectl
```

Drain the worker node

kubectl drain node01 --ignore-daemonsets

Go to worker node
```
ssh node01
```

Upgrade kubeadm

apt-get update
apt-mark unhold kubeadm
apt-get install -y kubeadm=1.27.0-00

Upgrade node
```
kubeadm upgrade node
```

Upgrade the kubelet

apt-mark unhold kubelet
apt-get install kubelet=1.27.0-00
systemctl daemon-reload
systemctl restart kubelet

Re-hold packages
```
apt-mark hold kubeadm kubelet
```
Return to controlplane
```
exit
```
Reinstate worker node
```
kubectl uncordon node01
```
Verify gold-nginx is scheduled on controlplane node
```
kubectl get pods -o wide | grep gold-nginx
```

Print the names of all deployments in the admin2406 namespace in the following format...

This is a job for custom-columns output of kubectl

kubectl -n admin2406 get deployment -o custom-columns=DEPLOYMENT:.metadata.name,CONTAINER_IMAGE:.spec.template.spec.containers[].image,READY_REPLICAS:.status.readyReplicas,NAMESPACE:.metadata.namespace --sort-by=.metadata.name > /opt/admin2406_data

A kubeconfig file called admin.kubeconfig has been created in /root/CKA. There is something wrong with the configuration. Troubleshoot and fix it.

First, let's test this kubeconfig
```
kubectl get pods --kubeconfig /root/CKA/admin.kubeconfig
```
Notice the error message.

Now look at the default kubeconfig for the correct setting.
```
cat ~/.kube/config
```
Make the correction
```
vi /root/CKA/admin.kubeconfig
```
Test
```
kubectl get pods --kubeconfig /root/CKA/admin.kubeconfig
```

Create a new deployment called nginx-deploy, with image nginx:1.16 and 1 replica. Next upgrade the deployment to version 1.17 using rolling update.
```
kubectl create deployment nginx-deploy --image=nginx:1.16
kubectl set image deployment/nginx-deploy nginx=nginx:1.17 --record
```
You may ignore the deprecation warning.
A new deployment called alpha-mysql has been deployed in the alpha namespace. However, the pods are not running. Troubleshoot and fix the issue.

The deployment should make use of the persistent volume alpha-pv to be mounted at /var/lib/mysql and should use the environment variable MYSQL_ALLOW_EMPTY_PASSWORD=1 to make use of an empty root password.

Important: Do not alter the persistent volume.

Inspect the deployment to check the environment variable is set. Here I'm using yq which is like jq but for YAML to not have to view the entire deployment YAML, just the section beneath containers in the deployment spec.
```
kubectl get deployment -n alpha alpha-mysql  -o yaml | yq e .spec.template.spec.containers -
```
Find out why the deployment does not have minimum availability. We'll have to find out the name of the deployment's pod first, then describe the pod to see the error.
```
kubectl get pods -n alpha
kubectl describe pod -n alpha alpha-mysql-xxxxxxxx-xxxxx
```
We find that the requested PVC isn't present, so create it. First, examine the Persistent Volume to find the values for access modes, capacity (storage), and storage class name
```
kubectl get pv alpha-pv
```
Now use vi to create a PVC manifest
```
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: mysql-alpha-pvc
  namespace: alpha
spec:
  accessModes:
  - ReadWriteOnce
  resources:
    requests:
      storage: 1Gi
  storageClassName: slow
```

Take the backup of ETCD at the location /opt/etcd-backup.db on the controlplane node.

This question is a bit poorly worded. It requires us to make a backup of etcd and store the backup at the given location.

Know that the certificates we need for authentication of etcdctl are located in /etc/kubernetes/pki/etcd
```
ETCDCTL_API='3' etcdctl snapshot save \
  --cacert=/etc/kubernetes/pki/etcd/ca.crt \
  --cert=/etc/kubernetes/pki/etcd/server.crt \
  --key=/etc/kubernetes/pki/etcd/server.key \
  /opt/etcd-backup.db
```
Whilst we could also use the argument --endpoints=127.0.0.1:2379, it is not necessary here as we are on the controlplane node, same as etcd itself. The default endpoint is the local host.

Create a pod called secret-1401 in the admin1401 namespace using the busybox image....

The container within the pod should be called secret-admin and should sleep for 4800 seconds.

The container should mount a read-only secret volume called secret-volume at the path /etc/secret-volume. The secret being mounted has already been created for you and is called dotfile-secret.

Use imperative command to get a starter manifest

kubectl run secret-1401 -n admin1401 --image busybox --dry-run=client -o yaml --command -- sleep 4800 > admin.yaml

Edit this manifest to add in the details for mounting the secret

vi admin.yaml

Add in the volume and volume mount sections seen below

apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: null
  labels:
    run: secret-1401
  name: secret-1401
  namespace: admin1401
spec:
  volumes:
  - name: secret-volume
    secret:
      secretName: dotfile-secret
  containers:
  - command:
    - sleep
    - "4800"
    image: busybox
    name: secret-admin
    volumeMounts:
    - name: secret-volume
      readOnly: true
      mountPath: /etc/secret-volume

And create the pod
```
kubectl create -f admin.yaml
```

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Lightning Lab 1

Solution to LL-1

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Lightning Lab 1

Solution to LL-1