Image Pulling issue in Kubernetes deployment from Dockerhub registry - docker

Question

I am currently trying to implement the CI/CD pipeline using docker , Kubernetes and Jenkins. When I created the pipeline deployment Kubernetes deployment YAML file, I was not included the time stamp. Only I was using the imagePullPolicy as latest in YAML file. Regarding with latest pull I had already one discussion here, The following is the link for that discussion,
Docker image not pulling latest from dockerhub.com registry
After This discussion , I included the time stamp in my deployment YAML like the following,
apiVersion: apps/v1
kind: Deployment
metadata:
name: test-kube-deployment
labels:
app: test-kube-deployment
spec:
replicas: 3
selector:
matchLabels:
app: test-kube-deployment
template:
metadata:
labels:
app: test-kube-deployment
annotations:
date: "+%H:%M:%S %d/%m/%y"
spec:
imagePullSecrets:
- name: "regcred"
containers:
- name: test-kube-deployment-container
image: spacestudymilletech010/spacestudykubernetes:latest
imagePullPolicy: Always
ports:
- name: http
containerPort: 8085
protocol: TCP
Here I modified my script to include the time stamp by adding the following in template,
annotations:
date: "+%H:%M:%S %d/%m/%y"
My service file like following,
apiVersion: v1
kind: Service
metadata:
name: my-service
spec:
type: NodePort
ports:
- port: 8085
targetPort: 8085
protocol: TCP
name: http
selector:
app: test-kube-deployment
My jenkinsfile conatining the following,
stage ('imagebuild')
{
steps
{
sh 'docker build -f /var/lib/jenkins/workspace/jpipeline/pipeline/Dockerfile -t spacestudymilletech010/spacestudykubernetes:latest /var/lib/jenkins/workspace/jpipeline/pipeline'
sh 'docker login --username=<my-username> --password=<my-password>'
sh 'docker push spacestudymilletech010/spacestudykubernetes:latest'
}
}
stage ('Test Deployment')
{
steps
{
sh 'kubectl apply -f deployment/testdeployment.yaml'
sh 'kubectl apply -f deployment/testservice.yaml'
}
}
But still the deployment not pulling the latest one from Dockerhub registry. How I can modify these script for resolving the latest pulling problem?

Answer 1

The default pull policy is IfNotPresent which causes the Kubelet to skip pulling an image if it already exists. If you would like to always force a pull, you can do one of the following:
set the imagePullPolicy of the container to Always.
omit the imagePullPolicy and use :latest as the tag for the image to use.
omit the imagePullPolicy and the tag for the image to use.
enable the AlwaysPullImages admission controller.
Basically, either use :latest or then use imagePullPolicy: Always
Try it and let me know how it goes!
Referenced from here

Answer 2

There is many articles and docs that explain how to properly build and publish the docker image using Jenkins.
You should first read Using Docker with Pipeline which shows you an example with environment variable ${env.BUILD_ID}
node {
checkout scm
docker.withRegistry('https://registry.example.com', 'credentials-id') {
def customImage = docker.build("my-image:${env.BUILD_ID}")
/* Push the container to the custom Registry */
customImage.push()
}
}
Or to put it as a stage:
stage('Push image') {
docker.withRegistry('https://registry.hub.docker.com', 'docker-hub-credentials') {
app.push("${env.BUILD_NUMBER}")
app.push("latest")
}
}
I really do recommend reading Building your first Docker image with Jenkins 2: Guide for developers, which I think will answer many if not all of your questions.