KUBERNETES LEARNING PHASE 1 - BASIC COMMANDS

This post will only includes scenario based Kubernetes problem and the commands/debugging steps. It will be updated whenever I learn something new.

For Installation of Kubernetes refer here: https://kubernetes.io/docs/tasks/tools/

Case 1: Get all pods in a namespace

kubectl get pods -n <namespace_name>

Case 2: Get all namespaces

kubectl get namespaces 
OR
kubectl get ns

Case 3: Create pods with a name and image in a particular namespace

kubectl run <pod_name> --image=<image_name> -n <namespace>

e.g.

kubectl run redis --image=redis -n my-namespace

Case 4: Get all pods in all the namespaces

kubectl get pods --all-namespaces

Case 5: Get all replicasets

kubectl get replicaset

Case 6: Create pods using yaml file

kubectl apply -f abc.yml -n namespace

abc.yaml or abc.yml file:

apiVersion: v1
kind: Pod
metadata: 
  name: new-pod
  label:
    type: linux
spec:
  containers:
    -name: redis
     image: redis

Case 7: Create deployment using yaml file

kubectl apply -f deployment.yml

deployment.yml file is having

apiVersion: apps/v1
kind: Deployment
metadata:
  name: new-deployment
spec:
  replicas: 3
  selector:
    matchLabels:
      name: abc-pod
  template:
    metadata:
      labels:
        name: abc-pod
    spec:
      containers:
      - name: abc-container
        image: nginx
        command:
        - sh
        - "-c"
        - echo Hello Kubernetes! && sleep 3600

Here important points are:

• apiVersion should follow the way apps/v1 or apps/v

• kind is case sensitive

• matchlabels.name should be same as metadata.labels.name

• You can specify the replica number and that many pods will be created.

• When this deployment will be created, a replica set, 3 pods, one deployment will be created.

Case 8: Get all details of the pod

kubectl describe pod <pod_name> -n <namespace>

Case 9: Get all pods, replicaset, deployment and services present

kubectl get all

Case 10: Editing an existing replicaset

kubectl edit replicaset <replicaset_name>

There will be an another post soon dealing with more kubernetes day to day used commands.