> ## Documentation Index
> Fetch the complete documentation index at: https://notes.kodekloud.com/llms.txt
> Use this file to discover all available pages before exploring further.
# Demo Kubernetes Deploy Update Image Tag
> This tutorial automates updating Docker image tags in Kubernetes manifests using Jenkins and GitOps with Argo CD.
In this tutorial, we’ll automate updating the Docker image tag in Kubernetes manifests and commit changes back to a GitOps repository using a Jenkins pipeline, triggered by Git webhooks.
## Prerequisites
| Component | Description | Reference |
| ---------------- | ----------------------------------------------------------- | ------------------------------------------------------------------------------- |
| GitOps Repo | `solar-system-gitops-argo-cd` in Gitea under `dasher-org` | |
| Argo CD App | `solar-system-argo-app` tracking the `kubernetes` directory | [Argo CD Application](https://argo-cd.readthedocs.io/en/stable/user-guide/) |
| Jenkins Instance | Controller with credentials to push to Gitea | [Jenkins Credentials](https://www.jenkins.io/doc/book/using/using-credentials/) |
## 1. Inspect the Manifest Repository
Open the Gitea repo `solar-system-gitops-argo-cd` and navigate to the `kubernetes` folder:
Examine `deployment.yml`:
```yaml theme={null}
apiVersion: apps/v1
kind: Deployment
metadata:
name: solar-system
namespace: solar-system
spec:
replicas: 2
template:
spec:
containers:
- name: solar-system
image: siddharth67/solar-system:3e9063be059342b1916f020e034344fb267d1
imagePullPolicy: Always
ports:
- containerPort: 3000
```
## 2. Check Argo CD Application Status
Argo CD will show the application as **OutOfSync** before resources are applied:
Verify no resources exist in the `solar-system` namespace:
```bash theme={null}
kubectl get all -n solar-system
```
## 3. Jenkins Pipeline: Add “K8S Update Image Tag” Stage
Add a new declarative stage to your `Jenkinsfile` to:
* Run only on pull request branches (`PR*`).
* Clone the GitOps repo.
* Update the Docker image tag in `deployment.yml`.
* Commit & push to `feature-$BUILD_ID`.
Ensure the Jenkins agent has `git` and `sed` installed for cloning and file editing.
```groovy theme={null}
stage('K8S Update Image Tag') {
when { branch 'PR*' }
steps {
script {
if (fileExists('solar-system-gitops-argo-cd')) {
sh 'rm -rf solar-system-gitops-argo-cd'
}
}
sh 'git clone -b main http://64.227.187.25:5555/dasher-org/solar-system-gitops-argo-cd'
dir('solar-system-gitops-argo-cd/kubernetes') {
sh '''
git checkout main
git checkout -b feature-$BUILD_ID
sed -i "s#image: .*#image: siddharth67/solar-system:$GIT_COMMIT#g" deployment.yml
git config user.email "jenkins@dasher.com"
git config user.name "Jenkins"
git remote set-url origin http://$GITEA_TOKEN@64.227.187.25:5555/dasher-org/solar-system-gitops-argo-cd
git add deployment.yml
git commit -m "Update Docker image to $GIT_COMMIT"
git push -u origin feature-$BUILD_ID
'''
}
}
post {
always {
script {
if (fileExists('solar-system-gitops-argo-cd')) {
sh 'rm -rf solar-system-gitops-argo-cd'
}
}
}
}
}
```
## 4. Configure Gitea API Token
### 4.1 Generate Token in Gitea
In Gitea user settings, create a new access token named `jenkins-token` with **read/write** scope:
### 4.2 Add Token to Jenkins Credentials
Go to **Credentials > System > Global credentials** in Jenkins and add a **Secret text** credential with ID `gitea-api-token`:
Reference it:
```groovy theme={null}
environment {
GITEA_TOKEN = credentials('gitea-api-token')
}
```
Keep your API tokens secure. Do not hardcode secrets in your `Jenkinsfile`.
## 5. Webhook Trigger on Pull Requests
Configure a Gitea webhook to trigger Jenkins on pull request events:
Enable **Pull request events**:
### 5.1 Create a Pull Request
Open a new PR against `main`:
### 5.2 Observe Jenkins Pipeline Runs
Jenkins will build the PR branch and run the image update:
View the pipeline activity dashboard:
## 6. Confirm Image Tag Update
Check console logs:
```bash theme={null}
git clone -b main http://64.227.187.25:5555/dasher-org/solar-system-gitops-argo-cd
git checkout -b feature-1
sed -i "... deployment.yml"
git commit -am "Update Docker image to f5c47d71240f57467b284288f1c452f81341b"
git push -u origin feature-1
```
Inspect the `feature-1` branch in Gitea:
## 7. Sync with Argo CD
Since Argo CD tracks `main`, it remains **OutOfSync** until you merge `feature-1`:
Next, automate merging `feature-1` into `main` so Argo CD can deploy the updated manifest.
## Links and References
* [Kubernetes Documentation](https://kubernetes.io/docs/)
* [Argo CD User Guide](https://argo-cd.readthedocs.io/)
* [Jenkins Pipeline Syntax](https://www.jenkins.io/doc/book/pipeline/syntax/)
* [Gitea Webhooks](https://docs.gitea.io/en-us/webhooks/)
Thank you for following this GitOps workflow!