- What is Kubernetes
- Kubernetes High Level Architecture
- Control Plane
- Kubernetes Tools
- What is Minikube
- Minikube Installation
- Install Curl
- Install docker
- Install Minikube
- Minikube Run
- Output of minikube start and status
- Install Kubectl
- Verify and Run Minikube Cluster
- This article intended for the purpose of getting started with Kubernetes basics
- It also explains about setting up the labs environment to run the basic Kubernetes commands.
- You can consider this blog as scribble pad that is used while getting started with Kubernetes
Kubernetes(also called a
K8s) is a Container orchestration open-source platform.
- Kubernetes builds upon 15 years of experience of running production workloads at Google, combined with best-of-breed ideas and practices from the community.
- We can manage containerised workloads and services, that facilitates both declarative configuration and automation.
- It has a large, rapidly growing ecosystem. Kubernetes services, support, and tools are widely available.
- Refer Documentation for more details
Kubernetes to two major building blocks,
Control Plane (or
Master Node as called previously)
Worker Node as called previously)
Master node has four major components,
1. Kube API Server : This component exposes Kubernetes API and acts as a front end of k8s control plane.
kubectl is used to interact with API servers.
2. ETCD : Secure key-value store
3. Kube Scheduler : Watches newly created Pod with and selects node for those pods to run
4. Controller Manager : This component manages the four controller processes of Kubernetes
- Node Controller
- Job Controller
- End-point Controller
- Service account & Token Controller
A node consists of,
1. Kubelet : An agent that runs on each node in the cluster. It makes sure that containers are running in a Pod.
2. Kube-proxy : kube-proxy is a network proxy that runs on each node in your cluster, implementing part of the Kubernetes Service concept.
3. Container Runtime : The container runtime is the software that is responsible for running containers.
Kubernetes supports several container runtimes: Docker, containerd, CRI-O, and any implementation of the Kubernetes CRI (Container Runtime Interface).
4. Pods : Pods are the smallest deploy-able units of computing that we can create and manage in Kubernetes.
A Pod (as in a pod of whales or pea pod) is a group of one or more containers, with shared storage and network resources, and a specification for how to run the containers.
Refer Kubernetes Component Documentation for more details.
There are various tools available to learn Kubernetes by doing the setup in Workstation
As part of learning and to practice Kubernetes, we will pick-up
minikube installation steps and practice lessons.
minikubeis a CLI tool that lets you run Kubernetes locally on any workstation.
- It runs a single-node Kubernetes cluster on our personal computer (including Windows, macOS and Linux OS) so we can try out Kubernetes learning, and for any daily development work.
- Minikube cluster packs both the master and worker components for us to get started with managing the container.
- Below diagram depicts the minikube single node cluster,
In order to getting started with
minikube, we need to install below components in our workstation
I have carried out the steps in
Ubuntu 21.04based operating system
minikubedocumentation for installation steps for other operating systems
sudo apt update sudo apt install curl -y
# Update the apt package index, and install the latest version of Docker Engine and containerd, # or go to the next step to install a specific version: sudo apt update -y sudo apt install -y docker-ce docker-ce-cli containerd.io # Add current user to 'docker' user group to invoke minikube (otherwise, the .sock permission denied error will occur) sudo usermod -aG docker $USER newgrp docker # Verify that Docker Engine is installed correctly by running the hello-world image. sudo docker run hello-world
cd /tmp curl -LO https://storage.googleapis.com/minikube/releases/latest/minikube_latest_amd64.deb sudo dpkg -i minikube_latest_amd64.deb
minikubecluster and provide docker as the container runtime engine
$ minikube start --driver=docker
- It will show up the below output in console
😄 minikube v1.22.0 on Ubuntu 21.04 ✨ Using the docker driver based on user configuration 👍 Starting control plane node minikube in cluster minikube 🚜 Pulling base image ... 💾 Downloading Kubernetes v1.21.2 preload ... > preloaded-images-k8s-v11-v1...: 502.14 MiB / 502.14 MiB 100.00% 7.75 MiB > gcr.io/k8s-minikube/kicbase...: 361.09 MiB / 361.09 MiB 100.00% 5.08 MiB 🔥 Creating docker container (CPUs=2, Memory=3900MB) ... 🐳 Preparing Kubernetes v1.21.2 on Docker 20.10.7 ... ▪ Generating certificates and keys ... ▪ Booting up control plane ... ▪ Configuring RBAC rules ... 🔎 Verifying Kubernetes components... ▪ Using image gcr.io/k8s-minikube/storage-provisioner:v5 🌟 Enabled addons: storage-provisioner, default-storageclass 💡 kubectl not found. If you need it, try: 'minikube kubectl -- get pods -A' 🏄 Done! kubectl is now configured to use "minikube" cluster and "default" namespace by default
- Minikube status command,
$ minikube status minikube type: Control Plane host: Running kubelet: Running apiserver: Running kubeconfig: Configured
Please note, Installation of Kubectl is options, because
minikube comes packed desired version of
so, if we don't install
kubectl explicitly, then we can invoke
kubectl commands as below,
minikube kubectl -- <expected kubectl command>
If we explicitly installed
kubectl, then we can invoke
kubectl commands directly as below,
kubectl <expected kubectl command>
Kubectl installation steps,
Run below commands to install kubectl in
sudo snap install kubectl --classic kubectl version
- We can use
kubectlcommands to verify the installed cluster and other details.
- We can use it to access our new cluster created using
kubectl get po -A
minikube kubectl -- get po -A
- It shows the below output, which shows the deployed single node cluster created using
- Please note components from control plane and worker node available as part of minikube deployment
$ kubectl get po -A NAMESPACE NAME READY STATUS RESTARTS AGE kube-system coredns-558bd4d5db-4tncm 1/1 Running 5 9d kube-system etcd-minikube 1/1 Running 5 9d kube-system kube-apiserver-minikube 1/1 Running 5 9d kube-system kube-controller-manager-minikube 1/1 Running 5 9d kube-system kube-proxy-wtzn9 1/1 Running 5 9d kube-system kube-scheduler-minikube 1/1 Running 5 9d kube-system storage-provisioner 1/1 Running 10 9d kubernetes-dashboard dashboard-metrics-scraper-7976b667d4-cssj8 1/1 Running 5 9d kubernetes-dashboard kubernetes-dashboard-6fcdf4f6d-kqr78 1/1 Running 10 9d
- Then, we can try performing the creation of new k8s deployments,
minikube kubectl -- create deployment hello-minikube --image=k8s.gcr.io/echoserver:1.4 minikube kubectl -- expose deployment hello-minikube --type=NodePort --port=8080 minikube kubectl -- get services hello-minikube minikube service hello-minikube
- The entire Minikube cluster can be visualised using the below command,
- We have come to the end of kubernetes getting started tutorial - part 1
- Try this out and start hands-on with Kubernetes
- We will see, next level topics like deployment of pods and services in part 2