Simple CICD with Jenkins

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What is CICD ?

CI/CD stands for Continuous Integration and Continuous Deployment (or Continuous Delivery), a set of practices in DevOps to automate software development and deployment. It helps teams release software more frequently, reliably, and efficiently. Here’s a breakdown:

1. Continuous Integration (CI)

In CI, developers regularly merge their code changes into a central repository. Automated tests run on each change to verify it works and doesn’t break the main codebase.

This practice detects issues early, making them easier and cheaper to fix.

2. Continuous Delivery (CD)

Continuous Delivery ensures that every change that passes the CI process is automatically prepared for release to production.

Although deployment can be automated or manual, the goal is to keep code in a release-ready state.

3. Continuous Deployment (CD)

Continuous Deployment takes Continuous Delivery a step further. Every code change that passes tests is automatically released to production without manual intervention.

This practice is common for web applications where frequent updates are expected.

Benefits of CI/CD:

Faster release cycles and quicker feedback on code.

Reduced bugs due to automated testing.

Easier collaboration among developers.

Increased stability in production environments.

CI/CD is typically managed using CI/CD pipelines, which automate building, testing, and deploying applications through tools like Jenkins, GitLab CI, CircleCI, and GitHub Actions.

So in this practice i will show simple CICD , the tech stack I will use is :

Jenkins

Docker

Nginx

Github

Ubuntu server 20.04

Server OS i am used

Make sure you have docker installed in your host system

1. GITHUB

First we need to create repository

Then create name your repository make it Public access

Then we are ready to craete new repository

After repository created, click create new repository

Just create new file Readme.md fill it with description project and commit changes to save it

The commit message we can set is as default

then we can see in our repository have a file named Readme.md

then we can clone the repository

Login Git

Method with SSH

Generate SSH Key

Store ~/.ssh/id_rsa.pub in github

Copy all content of file id_rsa.pub and store it into github

Go to repository and settings

Select Deploy Key

Paste content .pub and save with click add key dont forget to checkmark Allow Write Access

Test the connection

Now my github account connected with my server

Git Clone

Click code copy links SSH

then we clone it to our Ubuntu Server

If success its will create new repository and check folder with command

then go to inside repository and check the file

voila !!! there is a file that we created earlier before. You can check what is GIT and what is Github

Next i will show you create new files in our server and commit to my github

Commit Docker Compose

first create new file. make sure in cli directory is on your repository directory

write in docker-compose

create new folder and create new file index.html

fill with Hello yourname or something

then save it.

Here's how to commit and push your changes to a Git repository:

Stage Changes: Add the files you want to commit (use . to add all changes).

Commit Changes: Create a commit message describing your changes.

Push to Remote Repository: Send your commit to the remote Git repository.

now you can check into your github page

There its, we have successfully update into our Github repository

2. Docker Container

go to your repository directory run the container

make sure the container running, container nginx will run on port 8080

then check to your ubuntu IP:port-nginx

in my case my ubuntu IP is 192.168.56.2 and nginx port used is 8080 so i will access 192.168.56.2:8080

why access using port 8080 ?

in my docker compose its using

so the port 8080 is used for access public, and port 80 is for networking internal inside docker. more info in Docker Docs

after make sure deployment is success I will push it to Github

Create CICD

After setup github repository we are ready to create our first CICD, the first thing we need is JENKINS.

Deploy Jenkins

I am creating new folder for jenkins

here is my docker compose

so here is currently my directory looks like inside Simple-CICD-Nginx

and deploy apps

🚧

to more detail installing jenkins you can check in my post Install Jenkins

Add Plugins

Click Manage Jenkins

Click Plugins

Go to Available Plugins search SSH Agents and click Check box then click Button Install

Scroll Down and Click Checkbox Restart Jenkins

After Success restart we can make sure SSH Agents installed or not in Installed Plugins

There its, My SSH Agent is success installed, then return to Dashboard . We are ready to create our first pipeline

Create Pipeline

Click New Item

Input Name CICD and Select Pipeline

after OK you need to Configure the CICD, Scroll down and find pipeline, Change it into Pipeline script from SCM

Add your repository URL, use the HTTPS and branch change to */main

thennnn save it !!! oke, the pipeline is ready. but we are missing crucial step its the Jenkinsfile script. In Jenkinsfile you describe how the CICD flow, first lets test to create Test Jenkinsfile

Create Test Jenkinsfile

I am showing add file from github, its will more easy to edit the text from github right know.

Back to your github add file

Name file with Jenkinsfile

write Jenkinsfile

here is the code

save it / Commit changes

after saved now in our repository is have Jenkinsfile

ok now, back to Jenkins Page

Try click build now

its will trigger new builds. if its green then its success. try to click it

if you click Builds #2 you will get more detail about pipeline

Lets check the Console Output

Hey there is an output from echo 'Hello, this is a test pipeline!' its from Jenkinsfile that writed before. its mean the Jenkinsfile is running successfully for step Test Echo lets try add new steps in Jenkinsfile

I am add Test Echo 2 into Jenkinsfile, you can edit Jenkinsfile from Github. Just click Jenkinsfile and click pencil to edit

Click Edit

Commit Changes to save it

Back again to Jenkins page, and hit Build now again

OK after Build now Clicked in Builds will increased, and check again the Console Output

Hey there its, its my new step Test Echo 2 . OK so i am assumed you are already know how Jenkinsfile works. Next step is I will show how to Automate Trigger build, and deploy to our VM.

Setup SSH

Since the CICD will ssh into VM we need to add credentials in Jenkins. Click profile then Click Credentials

Click Global and Add Credentials

Select SSH Username and private key

since we are already create ssh key, we can use it again

in ID type ssh-to-vm and username is the username of your VM, in here i will use kazami

next for private key click Add

copy private key from

Copy all text to the very bottom text -----END OPENSSH PRIVATE KEY-----

paste into Jenkins

ok, click Create to save it

ok before run the pipeline we need to add SSH key into authorized_keys to do it just write pub key into authorized_keys, with doing these its allowing SSH into server without using password