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Installing Kubernetes

This guide uses MiniKube/MiniShift to demonstrate deployment and operation of Pystol in a single-node Kubernetes cluster.

Table of contents

  1. Pre-requirements
  2. Installing Minikube in CentOS 8
    1. Prepare the hypervisor node
    2. Check that the kernel modules are OK.
    3. Enable libvirtd, disable SElinux xD and firewalld.
    4. Install Minikube.
    5. Create the toor user (from the Hypervisor node, as root).
    6. Install Docker.
    7. Finish the Minikube configuration.
    8. Start Minikube.
  3. Minikube cheat sheet.
  4. Result

Pre-requirements

The MiniKube/MiniShift VM requires approximately 4GB of RAM and supports hypervisors like VirtualBox/HyperV/KVM that run on Linux, macOS, and Windows.


Installing Minikube in CentOS 8

The following steps need to run in the Hypervisor machine in which you will like to have your Minikube deployment.

Prepare the hypervisor node

Now, let’s install some dependencies. Same Hypervisor node, same root user.

# In this dev. env. /var is only 50GB, so I will create
# a sym link to another location with more capacity.
sudo mkdir -p /home/libvirt/
sudo ln -sf /home/libvirt/ /var/lib/libvirt

sudo mkdir -p /home/docker/
sudo ln -sf /home/docker/ /var/lib/docker

# Install some packages
sudo yum install dnf -y
sudo dnf update -y
sudo dnf groupinstall "Virtualization Host" -y
sudo dnf install libvirt qemu-kvm virt-install virt-top libguestfs-tools bridge-utils -y
sudo dnf install git lvm2 lvm2-devel -y
sudo dnf install libvirt-python python-lxml libvirt curl-y
sudo dnf install binutils qt gcc make patch libgomp -y
sudo dnf install glibc-headers glibc-devel kernel-headers -y
sudo dnf install kernel-devel dkms bash-completion -y
sudo dnf install nano wget -y
sudo dnf install python3-pip -y

Check that the kernel modules are OK.

# Check the kernel modules are OK
sudo lsmod | grep kvm

Enable libvirtd, disable SElinux xD and firewalld.

# Enable libvirtd
sudo systemctl start libvirtd
sudo systemctl enable libvirtd

# Disable selinux & stop firewall as needed.
setenforce 0
perl -pi -e 's/SELINUX\=enforcing/SELINUX\=disabled/g' /etc/selinux/config
systemctl stop firewalld
systemctl disable firewalld

Install Minikube.

#Install minikube
/usr/bin/curl -Lo minikube https://storage.googleapis.com/minikube/releases/latest/minikube-linux-amd64 && chmod +x minikube
cp -p minikube /usr/local/bin && rm -f minikube

# Create the repo for kubernetes
cat << EOF > /etc/yum.repos.d/kubernetes.repo
[kubernetes]
name=Kubernetes
baseurl=https://packages.cloud.google.com/yum/repos/kubernetes-el7-x86_64
enabled=1
gpgcheck=1
repo_gpgcheck=1
gpgkey=https://packages.cloud.google.com/yum/doc/yum-key.gpg https://packages.cloud.google.com/yum/doc/rpm-package-key.gpg
EOF

# Install kubectl
sudo dnf install kubectl -y
source <(kubectl completion bash)
echo "source <(kubectl completion bash)" >> ~/.bashrc

Create the toor user (from the Hypervisor node, as root).

sudo useradd toor
echo "toor:toor" | sudo chpasswd
echo "toor ALL=(root) NOPASSWD:ALL" \
  | sudo tee /etc/sudoers.d/toor
sudo chmod 0440 /etc/sudoers.d/toor
sudo su - toor

cd
mkdir .ssh
ssh-keygen -t rsa -N "" -f .ssh/id_rsa

Now, follow as the toor user and prepare the Hypervisor node for Minikube.

Install Docker.

Note: There is no Docker in Centos 8 we will use Podman.

sudo dnf install podman podman-docker -y

Finish the Minikube configuration.

# Add to bashrc in toor user
source <(kubectl completion bash)
echo "source <(kubectl completion bash)" >> ~/.bashrc

# We add toor to the libvirtd group
sudo usermod --append --groups libvirt toor

Start Minikube.

minikube start --disk-size=300GB --memory=65536 --cpus=4 --vm-driver kvm2
export no_proxy=$no_proxy,$(minikube ip)
nohup kubectl proxy --address='0.0.0.0' --port=8001 --disable-filter=true &
sleep 30
minikube addons enable dashboard
nohup minikube dashboard --url &
minikube addons open dashboard

The Minikube instance should be reachable from the following URL:

http://machine_ip:8001/api/v1/namespaces/kubernetes-dashboard/services/http:kubernetes-dashboard:/proxy/

# To stop/delete
kubectl delete deploy,svc --all
minikube stop
minikube delete

Minikube cheat sheet.

# set & get current context of cluster
 kubectl config use-context minikube
 kubectl config current-context

# fetch all the kubernetes objects for a namespace
 kubectl get all -n kube-system

# display cluster details
 kubectl cluster-info

# set custom memory and cpu
 minikube config set memory 4096
 minikube config set cpus 2

# fetch cluster ip
 minikube ip

# ssh to the minikube vm
 minikube ssh

# display addons list and status
 minikube addons list

# exposes service to vm & retrieves url
 minikube service elasticsearch
 minikube service elasticsearch --url

Result

In any case you should have your containers platform deployed successfully and ready to start your development and tests.