Database Admin - Kubernetes cheat sheet

 Kubernetes cheat sheet

Listing the below commands which will be useful for administering the kubernetes environment.

 

Version:

# Get kubernetes version: The Server Version line indicates the version of Kubernetes that is running on the Kubernetes cluster.

kubectl version

Pods:

# Get the details of all pods in one namespace

kubectl get pods -n <namespace>

#  Get the details of all pods in all namespaces

kubectl get pods --all-namespaces 

#  Get the details of all pods in the current namespace, with more details

kubectl get pods -o wide  

Deployments:

# Get all  the deployments 

kubectl get deployments

# Check the history of deployments including the revision

Kubectl rollout history deployment <deployment name>

# Rolling  restart of the deployment

Kubectl rollout restart deployment <deployment name>

Interacting with pods:

# Login to pod

Kubectl exec -it <podname> -- bash

#Run the commands in the pod

Kubectl exec <podname> -- ls /

configmap :

# Get all configmap in current namespace

Kubectl get cm

# Edit configmap 

Kubectl edit cm <configmap name>

Secrets:

# Display all the secrets 

Kubectl get secrets

# Display all the secrets 

Kubectl get secrets --all-namespaces 

Services:

# Display all the services 

Kubectl get svc

# List Services Sorted by Name

kubectl get services --sort-by=.metadata.name

Logs:

# Check the logs of the pod

kubectl logs <podname>

# Tail the logs of the pod

kubectl logs -f <podname>

Copy :

# copy  the data from local directory to  the pod

kubectl cp $HOME/data <pod>:/opt/app/data

Storage:

# List all PersistentVolumes

kubectl get pv

# List all PersistentVolumes sorted by capacity

kubectl get pv --sort-by=.spec.capacity.storage

# Describe specific persistent volume

kubectl describe pv <pv_name>

# List all persistent volumes claims

kubectl get pvc

# Describe specific persistent volume claim

kubectl describe pvc <pvc_name>

Create/Delete resources:

# Create specific resource

kubectl apply -f <deployment>.yaml

# Create specific resource using URL

kubectl apply -f https://gcs.io/pod

# Describe specific persistent volume claim

kubectl delete -f <deployment>.yaml

Formatting output:

# Append the following to command to get output in json format 

-o json  

# Append the following to command to get output in yaml format 

-o yaml

# Append the following to command to get output in plain text format with additional information for pods.

-o wide

# Print a table using a comma separated list of custom columns

-o=custom-columns=<spec> 

Cluster details:

# Display the cluster details

kubectl cluster-info

Below bash alias are more useful:

    alias k="kubectl"

    alias allpods="kubectl get pods --all-namespaces"

    alias kc="kubectl create -f"

    alias kg="kubectl get"

    alias pods="kubectl get pods"

    alias ktop="kubectl top nodes"

    alias rcs="kubectl get rc"

    alias sv="kubectl get services"

    alias dep="kubectl get deployment"

    alias kd="kubectl describe"

    alias kdp="kubectl describe pod "

    alias kds="kubectl describe service "

    alias nodes="kubectl get nodes"

    alias klogs="kubectl logs"

    alias ns="kubectl get ns"

    alias deploys="kubectl get deployment"

    alias events="kubectl get events"

    alias kexec="kubectl exec -it "

    alias sec="kubectl get secrets"