Deploying A WordPress Application In Kubernetes Cluster Using Kubeadm Tool In AWS EC2 Instances

TABLE OF CONTENT

1. Introduction

2. Deployment Architecture

3. Prerequisites

4. Kubernetes Components Leveraged

5. A Brief Overview of the steps involved

6. Step-by-Step Guide

7. Conclusion

8. About CloudThat

9. FAQs

1. Introduction

In this blog, we will create a Kubernetes multi-node Cluster in a Virtual Machine Instance (EC2) and deploy a WordPress application on top of it.

Here, I am developing a cluster that gives us complete control over the nodes.

2. Deployment Architecture

3. Perquisites:

To Deploy a WordPress application in Kubernetes, you will need the following:

An AWS account
Kubeadm Tool
Calico Network plugin
Docker

4. Kubernetes Components Leveraged:

Deployment
Stateful set
Services
Secrets
Volumes
3 EC2 instances: One master node, two worker nodes

5. A brief overview of the steps involved:

Launching three instances
Setup kubeadm cluster
Joining the worker nodes with the master node
Deploying WordPress application

6. Step-by-Step Guide

Step 1: Create three instances of t3.medium running ubuntu 20.14 in the AWS console in any region.

Step 2: Add the security group Kubernetes-related port number and calico port number

Step 3: Tag one Instance as a Master node,

Remaining instances as worker one and worker two nodes.

SSH into the master and worker instance and Run the following commands.

#REMOVE OLD DOCKER

sudo apt-get remove docker docker-engine docker.io contained runs

1	sudo apt-get remove docker docker-engine docker.io contained runs

#INSTALL DOCKER PRE-REQUISITES

sudo apt-get update
sudo apt-get install -y apt-transport-https ca-certificates curl gnupg lsb-release

1 2	sudo apt-get update sudo apt-get install -y apt-transport-https ca-certificates curl gnupg lsb-release

#ADD GPG KEY

curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /usr/share/keyrings/docker-archive-keyring.gpg
echo \
  "deb [arch=amd64 signed-by=/usr/share/keyrings/docker-archive-keyring.gpg] https://download.docker.com/linux/ubuntu \
  $(lsb_release -cs) stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null

curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /usr/share/keyrings/docker-archive-keyring.gpg

echo \

"deb [arch=amd64 signed-by=/usr/share/keyrings/docker-archive-keyring.gpg] https://download.docker.com/linux/ubuntu \

$(lsb_release -cs) stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null

#INSTALL DOCKER ENGINE

sudo apt-get update
sudo apt-get install -y docker-ce docker-ce-cli containerd.io
sudo docker run hello-world
cat <<EOF | sudo tee /etc/modules-load.d/k8s.conf
overlay
br_netfilter
EOF

sudo apt-get update

sudo apt-get install -y docker-ce docker-ce-cli containerd.io

sudo docker run hello-world

cat <<EOF | sudo tee /etc/modules-load.d/k8s.conf

overlay

br_netfilter

EOF

# Restart nodes to load them the br_netfilter and overlay

sudo modprobe overlay
sudo modprobe br_netfilter

1 2	sudo modprobe overlay sudo modprobe br_netfilter

#ALLOW BRIDGED TRAFFIC FOR KUBEADM

cat <<EOF | sudo tee /etc/sysctl.d/k8s.conf
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
EOF
sudo sysctl --system

cat <<EOF | sudo tee /etc/sysctl.d/k8s.conf

net.bridge.bridge-nf-call-ip6tables = 1

net.bridge.bridge-nf-call-iptables = 1

EOF

sudo sysctl --system

#INSTALL K8S PRE-REQUISITES

sudo apt-get update
sudo apt-get install -y apt-transport-https ca-certificates curl

1 2	sudo apt-get update sudo apt-get install -y apt-transport-https ca-certificates curl

#DOWNLOAD GOOGLE CLOUD PUBLIC SIGNINIG KEY

sudo curl -fsSLo /usr/share/keyrings/kubernetes-archive-keyring.gpg
https://packages.cloud.google.com/apt/doc/apt-key.gpg

1 2	sudo curl -fsSLo /usr/share/keyrings/kubernetes-archive-keyring.gpg https://packages.cloud.google.com/apt/doc/apt-key.gpg

# ADD K8S APT REPO

echo "deb [signed-by=/usr/share/keyrings/kubernetes-archive-keyring.gpg] 
https://apt.kubernetes.io/ kubernetes-xenial main" | sudo tee 
/etc/apt/sources.list.d/kubernetes.list

echo "deb [signed-by=/usr/share/keyrings/kubernetes-archive-keyring.gpg]

https://apt.kubernetes.io/ kubernetes-xenial main" | sudo tee

/etc/apt/sources.list.d/kubernetes.list

# INSTALL K8S COMPONENTS

sudo apt-get update
 sudo apt-get install -y kubelet=1.20.1-00 kubeadm=1.20.1-00 kubectl=1.20.1-00
sudo apt-mark hold kubelet kubeadm kubectl
kubectl taint nodes --all node-role.kubernetes.io/master-
sudo touch /etc/docker/daemon.json
cat <<EOF | sudo tee /etc/docker/daemon.json
{
        "exec-opts": ["native.cgroupdriver=systemd"]
}
EOF
sudo swapoff –a      #to disable the swapping 
sudo sed -i '/ swap / s/^/#/' /etc/fstab      # To persist the swap disable

sudo apt-get update

sudo apt-get install -y kubelet=1.20.1-00 kubeadm=1.20.1-00 kubectl=1.20.1-00

sudo apt-mark hold kubelet kubeadm kubectl

kubectl taint nodes --all node-role.kubernetes.io/master-

sudo touch /etc/docker/daemon.json

cat <<EOF | sudo tee /etc/docker/daemon.json

{

"exec-opts": ["native.cgroupdriver=systemd"]

}

EOF

sudo swapoff –a #to disable the swapping

sudo sed -i '/ swap / s/^/#/' /etc/fstab # To persist the swap disable

#init

sudo systemctl daemon-reload
sudo systemctl restart docker

1 2	sudo systemctl daemon-reload sudo systemctl restart docker

Step 4: On the Master, node instance, follow the below commands to Initiate the Kubeadm, generate the token and Install Calico network plugin.

#Kubeadm init

kubeadm init --pod-network-cidr=10.244.0.0/16 --ignore-preflight-errors=all
export KUBECONFIG=/etc/kubernetes/admin.conf
sudo cp /etc/kubernetes/admin.conf $HOME/admin.conf
sudo chown $(id -u):$(id -g) $HOME/admin.conf

kubeadm init --pod-network-cidr=10.244.0.0/16 --ignore-preflight-errors=all

export KUBECONFIG=/etc/kubernetes/admin.conf

sudo cp /etc/kubernetes/admin.conf $HOME/admin.conf

sudo chown $(id -u):$(id -g) $HOME/admin.conf

#Generate Token

token=$(kubeadm token generate)
rm -f home/ubuntu/nodes-join-token.out
kubeadm token create $token --print-join-command --ttl=0 > /home/ubuntu/nodes-join-token.out
cat /home/ubuntu/nodes-join-token.out

token=$(kubeadm token generate)

rm -f home/ubuntu/nodes-join-token.out

kubeadm token create $token --print-join-command --ttl=0 > /home/ubuntu/nodes-join-token.out

cat /home/ubuntu/nodes-join-token.out

#Install calico networking

kubectl apply -f https://docs.projectcalico.org/manifests/calico.yaml
kubectl get cs
kubectl get components tatus
kubectl cluster-info
kubectl get pods -n kube-system

mv $HOME/.kube $OME/.kube.bak
mkdir $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config
sudo systemctl restart docker.service
sudo systemctl enable docker.service
sudo service kubelet restart

kubectl apply -f https://docs.projectcalico.org/manifests/calico.yaml

kubectl get cs

kubectl get components tatus

kubectl cluster-info

kubectl get pods -n kube-system

mv $HOME/.kube $OME/.kube.bak

mkdir $HOME/.kube

sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config

sudo chown $(id -u):$(id -g) $HOME/.kube/config

sudo systemctl restart docker.service

sudo systemctl enable docker.service

sudo service kubelet restart

Step 5: A file is created in the master node named “nodes-join-token”. Open it and copy the token

Cat nodes-join-token

1	Cat nodes-join-token

Step 6: Past the token in both the worker nodes to join them into the cluster.

Step 7: After the above step, run the below command in the master node to verify whether nodes are joined.

$:-Kubectl gets nodes

1	$:-Kubectl gets nodes

Successfully created Kubernetes Cluster using Kubeadm.

Step 8: SSH into the master node and execute the below code To Download the WordPress application.

#Install GIt

Sudo apt-get install git-all

1	Sudo apt-get install git-all

#make a directory

mkdir /home/ubuntu/Kubernetes 
cd /home/ubuntu/Kubernetes 
git init
git remote add kube https://github.com/v-karthik-kumar/kubernetes-karthik.git
git pull kube master

mkdir /home/ubuntu/Kubernetes

cd /home/ubuntu/Kubernetes

git init

git remote add kube https://github.com/v-karthik-kumar/kubernetes-karthik.git

git pull kube master

Step 9: Deploy yaml code in a sequence on the master nodes.

Step 9.1: Go to the Kubernetes directory

Cd /home/ubuntu/Kubernetes

1	Cd /home/ubuntu/Kubernetes

Step 9.2: Deploy persistent volume for MySQL

Kubectl apply -f pvMysql.yml

1	Kubectl apply -f pvMysql.yml

Step 9.3: Deploy persistent volume claim for MySQL

Kubectl apply -f  pvcMysql.yml

1	Kubectl apply -f pvcMysql.yml

Step 9.4: Deploy service for MySQL

Kubectl apply -f mysql-svc.yml

1	Kubectl apply -f mysql-svc.yml

Step 9.5: Deploy secrets

Kubectl apply -f  secret.yml

1	Kubectl apply -f secret.yml

Step 9.6: Deploy Deployment of mysql

Kubectl apply -f  mysql.yml

1	Kubectl apply -f mysql.yml

Step 9.7: Deploy persistent volume for WordPress

Kubectl apply -f  pvWordpress.yml

1	Kubectl apply -f pvWordpress.yml

Step 9.8: Deploy persistent volume claim for WordPress

Kubectl apply -f  pvcWordpress.yml

1	Kubectl apply -f pvcWordpress.yml

Step 9.9: Deploy service for WordPress

Kubectl apply -f wordpress-svc.yml

1	Kubectl apply -f wordpress-svc.yml

Step 9.10: Deploy Deployment of WordPress

Kubectl apply -f  wordpress.yml

1	Kubectl apply -f wordpress.yml

Step 10: Access the WordPress application in the browser.

http://<master/worker instance public Ip address>:30050

1	http://<master/worker instance public Ip address>:30050

7. Conclusion:

Kubeadm is the right tool to bootstrap the Kubernetes cluster on your virtual machines. Kubeadm sets up a minimal viable cluster. It is designed to have all the components you need in one place in one cluster regardless of where you are running them. An advantage of kubeadm is that it can be used anywhere —even Raspberry Pi— to set up a cluster and try it out before committing to something like kops

8. About CloudThat

CloudThat is the official AWS Advanced Consulting Partner, Microsoft Gold Partner, and Google Cloud Partner, helping people develop knowledge on the cloud and help their businesses aim for higher goals using best in industry cloud computing practices and expertise. We are on a mission to build a robust cloud computing ecosystem by disseminating knowledge on technological intricacies within the cloud space. Our blogs, webinars, case studies, and white papers enable all the stakeholders in the cloud computing sphere.

Feel free to drop a comment or any queries that you have regarding AWS services, Kubernetes Engine, or consulting requirements and we will get back to you quickly. To get started, go through our Expert Advisory page and Managed Services Package that is CloudThat’s offerings.

9. FAQs:

What is the difference between minikube and kubeadm?

ANS: Both are Designed for testing, research, and learning. Minikube is a fast and straightforward solution for deploying a single-node Kubernetes cluster, but it is not a minimum viable solution and production-ready cluster. According to Kubeadm, it is a minimum viable and production-ready cluster and allows us to choose the runtime environment, although it has a docker by default.

Why is it needed to disable the memory swapping while installing the Kubernetes cluster?

ANS: It is highly necessary to disable memory swap before creating a kubeadm cluster. Because the scheduler in Kubernetes chooses the best node to deploy the newly provisioned resources like pods. If the swapping is allowed that leads to stability and performance issues in the Kubernetes cluster.

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WRITTEN BY Karthik Kumar P V

Karthik Kumar Patro Voona is a Research Associate (Kubernetes) at CloudThat Technologies. He Holds Bachelor's degree in Information and Technology and has good programming knowledge of Python. He has experience in both AWS and Azure. He has a passion for Cloud-computing and DevOps. He has good working experience in Kubernetes and DevOps Tools like Terraform, Ansible, and Jenkins. He is a very good Team player, Adaptive and interested in exploring new technologies.