This is the repository which shows how to get started with Kubernetes and has some basic commands and config files that you may need.

• Pod - A thin wrapper around one or more containers
• Node - The machines in a Kubernetes cluster
• Service - Provides a fixed IP address to a logical group of pods
• Ingress - An API object that manages external access to the services in a cluster, typically HTTP (DNS)
• ConfigMap - To store the configurtions
• Secret - To store the access key and secret or username or password
• Volumes - To have an external storage space
• Deployment - Responsible for how to roll out or roll back across versions of your app
• ReplicaSet - Ensures a defined number of pods are always running
• StatefulSet - For stateful apps like DB

• One or More API Servers: Entry point for REST / kubectl
• etcd: Distributed key/value store
• Controller-manager: Always evaluating current vs desired state
• Scheduler: Schedules pods to worker nodes

• Made up of worker nodes
• kubelet: Acts as a conduit between the API server and the node
• kube-proxy: Manages IP translation and routing

1. metadata : Has the name & labels For eg -

metadata:
  name: nginx-deployment
  labels:
    app: nginx

2. spec : Has the config specific to the kind i.e. whether we are writing the config file for a deployment or service. For eg -

spec:
  replicas: 1
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.16
        ports:
        - containerPort: 8080

3. status : Auto generated by the kubernetes. Maintains the acutal and desired state here and updates the state continously. The information comes from etcd.

• Template : In deployment config, it has its own metadata and spec which defines the pod. For eg -

  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.16
        ports:
        - containerPort: 8080

• Labels : In deployment config, it is there in metadata of both the deployment and the pods.

      labels:
        app: nginx

• Ports: In deployment & service config, it is there in spec to mention the port. Service target port should be the container port.
  

  • For container -

      ports:
      - containerPort: 8080
  

  • For service -

  ports:
  - protocol: TCP
    port: 80
    targetPort: 8080
  

• Selectors : In service config, it is used to make the connection between service and depolyment or its pods.

  selector:
    app: nginx

• To download minikube

• To download docker

• to set different drivers - I used docker in mine for windows.

minikube start --vm-driver=docker
kubectl get nodes
minikube status 
kubectl version

minikube delete
minikube status

minikube addons enable ingress
kubectl get pod -n kube-system

kubectl create deployment {deployement-name} --image={image-name}
For eg - kubectl create deployment nginx-depl --image=nginx

Similarly,
kubectl edit deployment {deployment-name}
For eg - kubectl edit deployment nginx-depl

kubectl delete deployment {deployment-name}

For example - If we try to make it for nginx, we need to follow the below steps -

vim nginx-deployment.yaml
kubectl apply -f nginx-deployment.yaml
kubectl get pod
kubectl get deployment

kubectl delete -f nginx-deployment.yaml

kubectl get nodes
kubectl get pod
kubectl get deployment
kubectl get replicaset
kubectl get services
kubectl get all -n {namespace-name}

kubectl logs {pod-name}
kubectl exec -it {pod-name} -- bin/bash