Step by Step guide for Kubernetes in Dockers (KIND)

Hashedin

Shubham Yadav and Manish Dave

12 Apr 2020

Objective

Setting up a Kubernetes cluster over VMs can cause a large overhead and cause other applications on the system to slow down. Thus, creating a containerized K8s cluster will reduce this overhead and is well suited for testing purposes. This means that a K8s cluster will have Docker containers instead of VMs as worker nodes.

 

Overview

 

KIND came into the picture when one of our clients had the requirement of deploying k8s cluster on local machines. This was more of a requirement to onboard the product team on the functionalities of Kubernetes and what k8s brings which other orchestration tools like Docker Swarm, Mesos and Hashicorp’s Nomad doesn’t have. Setting up a full-fledged cluster would not be possible on a single machine without hampering the productivity of a developer’s work. Hence the light-weight KIND was used to provide almost all the functionality of k8s without causing any more overhead on the machine.

Background

 

KIND is a tool for running local Kubernetes clusters using Docker container “nodes”. KIND is primarily designed for testing Kubernetes 1.11+.

 

Why KIND?

  1. Supports multi-node (including HA) clusters
  2. Customizable base and node images
  3. Can use your local Kubernetes branch
  4. Written in go, can be used as a library
  5. Can be used on Windows, MacOS, and Linux
  6. CNCF certified conformant Kubernetes installer

Use-Cases:

  1. KIND in a ci pipeline
  2. Local development
  3. Demos of newer Kubernetes features
  4. Kinder tooling to test kubeadm
  5. “/test pull-Kubernetes-e2e-kind” on Kubernetes PRs for faster e2e feedback. It should be roughly 15-20 minutes currently.

Prerequisites

 

These are the versions that have been tested and proved to work:

 

  1. Go Version : go1.11.5 darwin/amd64
  2. Docker Version: docker-ce-18.09.2

Additional Requirements

Git Version: 2.17.2

Kubectl Version: 1.13.4 – 1.14.1

How to set up the k8s-cluster with KIND on MacOS?

 

Installing brew:

/usr/bin/ruby -e “$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)”

 

Installing wget:

brew install wget

 

Installing git :

brew install git

 

Installing kubectl:

To download version v1.14.0 on macOS, type:

curl -LO https://storage.googleapis.com/kubernetes-release/release/v1.13.4/bin/darwin/amd64/kubectl

 

Make the kubectl binary executable :

chmod +x ./kubectl

 

Move the binary into your PATH :

sudo mv ./kubectl /usr/local/bin/kubectl

kubectl version

 

Making a cluster directory:

mkdir cluster

cd cluster

wget https://dl.google.com/go/go1.11.5.darwin-amd64.tar.gz

tar -xzf  go1.11.5.darwin-amd64.tar.gz

 

The above action will create a folder named go with the binary files in it. Now we will export the go path and put the same in ~/.bash_profile to be working even after we log-off from the user.

 

export PATH=$PATH:$HOME/cluster/go/bin

 

Now run go version and it will give the go version extracted.

Put the same entry in bash_profile. If the file doesn’t exist then create one as,

 

vim ~/.bash_profile

export PATH=$PATH:$HOME/cluster/go/bin

For making the changes to take effect immediately, run :

 

source ~/.bash_profile

Checking the go environment variables are set as they should be:

 

go env

 

will give the following output. Make sure that the $GOPATH and $GOROOT have different directories. 

Or

 

You can set up the GOPATH and GOROOT environment variables manually as:

 

export GOPATH=$HOME/go

export GOROOT=$HOME/cluster/go

 

Installing docker-ce:v18.09.2 from the following link:

https://hub.docker.com/editions/community/docker-ce-desktop-mac

Or 

wget https://download.docker.com/mac/stable/Docker.dmg

and install the same.

 

 

Set CPUs to 4

Memory to 2.0 GiB

 

Check the docker version from CLI to confirm that the docker is successfully installed.

 

Now we will get KIND for setting up k8s-cluster:

go get -u sigs.k8s.io/kind

 

It is almost 1.58 GB and will take a little time after that it will create a KIND folder in the GOPATH directory.

export PATH=$PATH:$HOME/go/bin 

 

and add the same to ~/.bash_profile like previous additions.

 

kind version gives 0.3.0-alpha

 

Now for a KIND HA k8s-cluster we will need to create a configuration file:

 

Create a config.yml file in the directory cluster that we created initially. Get the following file from git repo:

 

wget https://github.com/shubhamsre/kind/blob/master/configha.yml

 

Run hostname to get the hostname of your system.

vim configha.yml

Change the hostname from my-hostname to your hostname

 

Now the power step is to run the setup for the cluster :

 

kind create cluster –name kindha –config configha.yml

 

The output is as follows:

 

 

 

Export the Kube-configuration as:

 

export KUBECONFIG=”$(kind get kubeconfig-path –name=”kindha”)”

kubectl cluster-info

 

The below results will be given somewhat resembling this:

 

 

 

All the nodes must get to the ready state and they may take some time for the same :

Run kubectl get nodes -o wide to get node status for Kubernetes Cluster

 

 

 

Adding alias for kubectl can be done as :

 

alias k=’kubectl’

 

and adding the same to the ~/.bash_profile.

 

You can add a role to the worker node as :

 

kubectl get nodes

 

kubectl label node kind-worker node-role.kubernetes.io/node=

 

 

The ~/.bash_profile should have the following contents:

export PATH=$PATH:$HOME/go/bin

export PATH=$PATH$HOME/cluster/go/bin

export KUBECONFIG=”$(kind get kubeconfig-path –name=”kindha”)”

alias k=’kubectl’

alias K=’kubeadm’

 

Error Messages and Troubleshooting

 

While Creating the Cluster if you encounter the following message:

 

        “failed to init node with kubeadm: exit status 1”

 

It shows that it is an error message stating that kubeadm cannot perform a certain task so you need to increase the CPU cores and memory for the system.

 

While Creating the Cluster if you come across the following message

 

     ” Error: could not list clusters: failed to list nodes: exit status 1″   

 

It means that this error message states that the docker is not running and before creating the cluster please ensure the docker is in running state.

 

 

 

      

 


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