Solution API VersionsDeprecations

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Short Names for Resources

kubectl api-resources

• Deployments: deploy
• ReplicaSets: rs
• CronJobs: cj
• Custom Resource Definitions: crd (or crds)

deployments                deploy
replicasets                rs
cronjobs                   cj
customresourcedefinitions  crd, crds

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Determining the API Group for a Resource

kubectl explain job

KIND: Job
VERSION: batch/v1

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Finding the Preferred Version for a Specific API Group

1. Start a Local API Proxy:
   Run the following command to create a local proxy to the Kubernetes API server:
   kubectl proxy --port=8001 &
   
2. Query the API Group Details:
   With the proxy running in the background, use curl to fetch the API group’s details:
   curl localhost:8001/apis/authorization.k8s.io
   

{
   "kind": "APIGroup",
   "apiVersion": "v1",
   "name": "authorization.k8s.io",
   "versions": [
      {
         "groupVersion": "authorization.k8s.io/v1",
         "version": "v1"
      }
   ],
   "preferredVersion": {
      "groupVersion": "authorization.k8s.io/v1",
      "version": "v1"
   }
}

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Enabling the v1alpha1 Version for RBAC.authorization.k8s.io

1. Backup the Current Manifest:
   The kube-apiserver manifest is located at /etc/kubernetes/manifests/kube-apiserver.yaml. Back it up with:
   cp /etc/kubernetes/manifests/kube-apiserver.yaml /root/kube-apiserver.yaml.backup
   
2. Modify the Manifest:
   Open the manifest file in your preferred text editor. Scroll down to the section containing command-line arguments and add the following flag at the bottom of the list:
   --runtime-config=rbac.authorization.k8s.io/v1alpha1
   
   Below is an excerpt from the modified section:
   --etcd-key-file=/etc/kubernetes/pki/apiserver-etcd-client.key
   --etcd-servers=https://127.0.0.1:2379
   --kubelet-client-certificate=/etc/kubernetes/pki/apiserver-kubelet-client.crt
   --kubelet-client-key=/etc/kubernetes/pki/apiserver-kubelet-client.key
   --kubelet-preferred-address-types=InternalIP,ExternalIP,Hostname
   --proxy-client-cert-file=/etc/kubernetes/pki/front-proxy-client.crt
   --proxy-client-key-file=/etc/kubernetes/pki/front-proxy-client.key
   --requestheader-allowed-names=front-proxy-client
   --requestheader-client-ca-file=/etc/kubernetes/pki/front-proxy-ca.crt
   --requestheader-extra-headers-prefix=X-Remote-Extra-
   --requestheader-group-headers=X-Remote-Group
   --requestheader-username-headers=X-Remote-User
   --secure-port=6443
   --service-account-issuer=https://kubernetes.default.svc.cluster.local
   --service-account-signing-key-file=/etc/kubernetes/pki/sa.pub
   --service-cluster-ip-range=10.96.0.0/12
   --tls-cert-file=/etc/kubernetes/pki/apiserver.crt
   --tls-private-key-file=/etc/kubernetes/pki/apiserver.key
   --runtime-config=rbac.authorization.k8s.io/v1alpha1
   image: k8s.gcr.io/kube-apiserver:v1.23.0
   imagePullPolicy: IfNotPresent
   livenessProbe:
     failureThreshold: 8
     httpGet:
       host: 10.69.230.9
       path: /livez
       port: 6443
       scheme: HTTPS
     initialDelaySeconds: 10
   
3. Verify the Update:
   After saving the changes, the kube-apiserver pod will automatically restart. Confirm its status by running:
   kubectl get pod -n kube-system
   
   Initially, the API server pod might display as Pending, but it should soon change to Running.

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Installing the kubectl-convert Plugin

1. Download the Plugin:
   Retrieve the binary using the commands below:
   curl -LO "https://dl.k8s.io/release/$(curl -L -s https://dl.k8s.io/release/stable.txt)/bin/linux/amd64/kubectl-convert"
   curl -LO "https://dl.k8s.io/release/stable.txt" | sha256sum --check
   
2. Make the Binary Executable and Move It:
   Change its permissions and move it to /usr/local/bin with these commands:
   chmod +x kubectl-convert
   mv kubectl-convert /usr/local/bin/
   
3. Verify the Installation:
   Execute the help command to ensure the plugin is installed correctly:
   kubectl convert --help
   

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Converting an Ingress Manifest

1. Convert the Manifest:
   The old ingress manifest is located at /root/ingress-old.yaml. Convert the API version using the following command:
   kubectl convert -f ingress-old.yaml --output-version networking.k8s.io/v1 > ingress-new.yaml
   
   This command creates a new file named ingress-new.yaml with the updated API version.
2. Apply the New Manifest:
   Deploy the updated Ingress configuration by running:
   kubectl apply -f ingress-new.yaml
   

ingress.networking.k8s.io/ingress-space created