CI/CD Setup with CircleCI

Kubernetes Auto Deploy: CI/CD Setup with CircleCI

In this guide

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using
**

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**You will set up an automatic deployment process in the environment.

The goal is to automatically publish the application with every code update to GitHub.

What Will You Learn in This Guide?

• Creating a CI/CD pipeline with CircleCI
• Producing a Docker image and sending it to the registry
• Automatic deployment to Kubernetes
• Use commit-based versioning

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Technical Summary

Topic: Automated CI/CD for Kubernetes
Problem: Manual deploy processes are error prone
Solution: CircleCI + Docker + Kubernetes automation

This structure:

• Triggered by GitHub push
• Works on container basis
• Provides scalable deployment

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Prerequisites

Before continuing, you must have the following ready:

• Kubernetes cluster (example:**

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  Kubernetes**)

• kubectl must be installed

• Docker information

• Docker Hub account

• GitHub account

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Access to Kubernetes Cluster

Once the cluster is created, test access to kubectl:

kubectl get nodes

• This command lists Kubernetes nodes.

If you see no resources found, access is successful.

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Creating the Git Project

1. Create a new folder for the sample application:

mkdir ~/k8s-sample-app && cd ~/k8s-sample-app
git init

• This repository will contain the CI/CD configuration.

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Creating a Service Account for CI/CD

1. It is not recommended for CI systems to connect with the admin user.

2. Create Service Account definition:

apiVersion: v1
kind: ServiceAccount
metadata:
  name: cicd
  namespace: default

• This account is used only for CI/CD operations.

Apply:

kubectl apply -f cicd-service-account.yml

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Role and RoleBinding Definition

1. Define Service Account privileges:

kind: Role
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: cicd
  namespace: default
rules:
  - apiGroups: ["", "apps"]
    resources: ["deployments", "services", "pods"]
    verbs: ["*"]

• This role grants access to core Kubernetes resources.

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Connect:

kubectl apply -f cicd-role.yml
kubectl apply -f cicd-role-binding.yml

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Sample Application with Docker

1. Create Dockerfile:

FROM nginx:1.21
COPY index.html /usr/share/nginx/html/index.html

• This image publishes static HTML.

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Create the image:

docker build -t kullaniciadi/k8s-sample-app .

Test:

docker run -p 8080:80 kullaniciadi/k8s-sample-app

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Kubernetes Deployment and Service

1. Deployment description:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: k8s-sample-app
spec:
  replicas: 1
  selector:
    matchLabels:
      app: k8s-sample-app
  template:
    metadata:
      labels:
        app: k8s-sample-app
    spec:
      containers:
        - name: app
          image: kullaniciadi/k8s-sample-app:latest
          ports:
            - containerPort: 80

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Service description:

apiVersion: v1
kind: Service
metadata:
  name: k8s-sample-app
spec:
  type: ClusterIP
  selector:
    app: k8s-sample-app
  ports:
    - port: 80
      targetPort: 80

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Apply:

kubectl apply -f kube/

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CircleCI Configuration

1. Create the .circleci/config.yml file:

version: 2.1
jobs:
  build:
    docker:
      - image: circleci/buildpack-deps:bullseye
    steps:
      - checkout
      - setup_remote_docker
      - run: docker build -t app:latest .
      - run: docker push app:latest

• This structure automatically generates the Docker image.

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Commit Based Deploy

1. Use commit hash instead of latest tag.

CircleCI variable:

$CIRCLE_SHA1

• In this way, each version is traceable.

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• Deployment is done via script:

kubectl apply -f kube/

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Frequently Asked Questions (FAQ)

1. Why do we use CircleCI? It's quick to install and integrated with GitHub.

2. Why is the latest tag not recommended? It makes version tracking difficult.

3. Is this structure suitable for prod? Yes, for small and medium-sized systems.

4. Can there be more than one environment? Yes, distinction can be made based on namespace.

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Result

With this guide:

You have established a CI/CD pipeline with CircleCI

You generated Docker images automatically

You provided automatic deployment to Kubernetes

You can use this structure scalably and securely on the GenixNode Kubernetes infrastructure.