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Readme.md

Kubenetes Basic

  • minikube start : Start minikube

  • kubectl cluster-info -> get cluster information

  • minikube ssh -> log into the Minikube VM

  • kubectl get nodes -> list cluster nodes

  • kubectl get pods -> list pods

NAME          READY     STATUS    RESTARTS   AGE
kubia-4jfyf   0/1       Pending   0          1m

Each pod is like a separate logical machine with its own IP, hostname, processes, and so on, running a single application. The application can be a single process, running in a single container, or it can be a main application process and additional supporting processes, each running in its own container. the pod's status can be pending when it's downloading the image from registry. when it's finished, a container will be created from the image and the status will be RUNNING.

  • Run a pod :
$ kubectl run kubia --image=tanvn84/kubia --port=8080 --generator=run/v1
replicationcontroller "kubia" created

Creating a LoadBalancer-type service, an external load balancer will be created, and the pod can be connected from outside through the load balancer's public IP.

$ kubectl expose rc kubia --type=LoadBalancer --name kubia-http
service "kubia-http" exposed

listing services :

tan.vu$ kubectl get services
NAME         TYPE           CLUSTER-IP      EXTERNAL-IP   PORT(S)          AGE
kubernetes   ClusterIP      10.96.0.1       <none>        443/TCP          18h
kubia-http   LoadBalancer   10.101.19.194   <pending>     8080:30263/TCP   32m

It takes time for the load balancer to be created by the cloud infrastructure.

Minikube doesn’t support LoadBalancer services, so the service will never get an external IP

When using Minikube, you can get the IP and port through which you can access the service by running minikube service kubia-http

Kubenetes does not create pods directly but via ReplicationController. ReplicationController control the number of pods, makes sure that it's always 1 pod running (when the number of pod is 1 by default). When a service is created, it gets a static IP which never changes during the service's lifetime.

Scale the number of pods :

$ kubectl scale rc kubia --replicas=3
replicationcontroller "kubia" scaled

Can see more information for each resource by

$ kubectl describe pod {pod-name}

Kubenetes Dashboard

A graphical web UI

  1. Google Kubernetes Engine
$ kubectl cluster-info | grep dashboard
kubernetes-dashboard is running at https://104.155.108.191/api/v1/proxy/

...
$ gcloud container clusters describe kubia | grep -E "(username|password):"
  1. Minikube
$ minikube dashboard