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Tips and tricks

Cheet sheet about all Kubernetes commands and contents.

Kubernetes cheat sheet​

See all node are running with more details​

kubectl get node --all-namespaces --output=wide

Short hand:

kubectl get node -A -o=wide
tip

In the Debian distribution, you can also use the built-in watch command, to run a command periodically:

watch --interval 1 kubectl get node --all-namespaces --output=wide

See all pods are running with more details and stay attach (--watch)​

kubectl get pods --all-namespaces -o=wide --watch

Apply directly yaml file in command line​

kubectl apply -f - <<EOF
apiVersion: v1
kind: Pod
metadata:
  name: my-pod
spec:
  containers:
    - name: my-pod
      image: mypod:latest
EOF

Set image to a delployment on the edge​

kubectl set image -n my-namespace deployment/my-deployment my-pod=my-registry-username/my-image:1.1.0

Remove taint if the Kubernetes cluster is a Single Node Cluster​

note

Read documentation about Single Node Cluster.

kubectl taint nodes <node-name> node-role.kubernetes.io/master:NoSchedule-

Add a label role to a node​

A node can be labeled with a key and value. The key and value are separated by a colon. The key and value can be any string.

When running this command, kubectl get node will show all nodes and their status, roles, age and version, as:

NAMESTATUSROLESAGEVERSION
masterReadycontrol-plane,master3d19hv1.21.5+k3s2
worker-0Readyworker3d19hv1.21.5+k3s2
worker-1Readyworker3d19hv1.21.5+k3s2
worker-2Readyworker3d19hv1.21.5+k3s2

To change the value of the role label, we can run the following command:

kubectl label nodes <list-of-nodes-separated-by-spaces> kubernetes.io/role=<role-name>
info

Here, we label the node with the key node-role.kubernetes.io/role and the value is worker.

info

This will allow us to filter nodes by the label node-role.kubernetes.io/role=worker.
This is useful when you want to run a command on a specific node (Read documentation about NodeSelector).

Get a k8s secret value and decode it​

kubectl get --all-namespaces secrets my-secret --template="{{index .data \"name-of-the-secret.key\"}}" | base64 --decode