How to Deploy a PHP App with Kubernetes on Ubuntu 16.04

Some words first

A container is a small sealed box that holds your app and everything it needs. Docker is a tool that builds containers. Kubernetes is a manager that runs many containers and restarts them if they fail. A pod is the smallest unit in Kubernetes. It holds one or more containers. A deployment tells Kubernetes how many copies of a pod to keep running.

You need a working Kubernetes cluster and the kubectl tool. A cluster is a group of servers that Kubernetes controls. Setting one up is a bigger job. If you have only one server, a small tool such as minikube can help for learning.

Steps

1. Install Docker:

sudo apt-get update
sudo apt-get install -y docker.io

This installs Docker from the Ubuntu package list.

2. Make a folder for your app and add a file index.php:

<?php echo "Hello from PHP on Kubernetes"; ?>

3. In the same folder, create a file named Dockerfile:

FROM php:7.4-apache
COPY index.php /var/www/html/

This starts from a ready-made PHP and Apache image and adds your file.

4. Build the image:

sudo docker build -t my-php-app:1.0 .

5. Make the image available to the cluster. Push it to a registry (an online store for images) that your cluster can reach. Local clusters may use the local image directly.
6. Create a file deployment.yaml:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: php-app
spec:
  replicas: 2
  selector:
    matchLabels:
      app: php-app
  template:
    metadata:
      labels:
        app: php-app
    spec:
      containers:
      - name: php-app
        image: my-php-app:1.0
        ports:
        - containerPort: 80

This asks for two copies of your app.

7. Apply it:

kubectl apply -f deployment.yaml

8. Expose the app so people can reach it:

kubectl expose deployment php-app --type=NodePort --port=80

9. Check the result:

kubectl get pods
kubectl get services

The pods should show Running. The service shows the port number to visit.

Quick recap

• Put your PHP app in a Docker image.
• Describe it in a deployment file.
• Apply the file with kubectl.
• Expose it with a service and check the pods.