Docker image as artifact in Jenkins - Step-by-Step Execution

Process Flow - Docker image as artifact

Start Jenkins Job

↓

Checkout Code

↓

Build Docker Image

↓

Tag Docker Image

↓

Push Image to Registry

↓

Use Image as Artifact in Next Steps

↓

End

This flow shows how Jenkins builds a Docker image, tags it, pushes it to a registry, and uses it as an artifact for later steps.

Execution Sample

Jenkins

pipeline {
  agent any
  stages {
    stage('Build') {
      steps {
        script {
          sh 'docker build -t myapp:${BUILD_NUMBER} .'
          sh 'docker push myapp:${BUILD_NUMBER}'
        }
      }
    }
  }
}

This Jenkins pipeline builds a Docker image tagged with the build number and pushes it to a Docker registry.

Process Table

Step	Action	Command Run	Result	Next Step
1	Start Jenkins Job	N/A	Job triggered	Checkout Code
2	Checkout Code	git clone repo	Code available locally	Build Docker Image
3	Build Docker Image	docker build -t myapp:1 .	Image 'myapp:1' created	Tag Docker Image
4	Tag Docker Image	Implicit in build command	Image tagged as 'myapp:1'	Push Image to Registry
5	Push Image to Registry	docker push myapp:1	Image pushed to registry	Use Image as Artifact
6	Use Image as Artifact	N/A	Image ready for deployment or next steps	End
7	End	N/A	Pipeline finished successfully	N/A

💡 Pipeline ends after image is pushed and ready as artifact for next steps.

Status Tracker

Variable	Start	After Step 3	After Step 5	Final
BUILD_NUMBER	1	1	1	1
Docker Image Tag	none	myapp:1	myapp:1	myapp:1
Image in Registry	no	no	yes	yes

Key Moments - 3 Insights

Why do we tag the Docker image with ${BUILD_NUMBER}?

Tagging with ${BUILD_NUMBER} creates a unique image version for each build, as shown in execution_table step 3 and 4, preventing overwriting previous images.

What happens if the docker push fails?

If docker push fails (step 5), the image is not stored in the registry and cannot be used as an artifact, so the pipeline usually stops or retries.

Is the image available locally after the build?

Yes, after step 3, the image is built and stored locally on the Jenkins agent before pushing to the registry.

Visual Quiz - 3 Questions

Look at the execution table, what is the Docker image tag after step 3?

A myapp:latest

B latest

C myapp:1

D none

💡 Hint

Check the 'Result' column in step 3 of the execution_table.

At which step is the Docker image pushed to the registry?

A Step 5

B Step 3

C Step 4

D Step 6

💡 Hint

Look for the 'Push Image to Registry' action in the execution_table.

If BUILD_NUMBER was '2', how would the Docker image tag change after step 3?

A myapp:1

B myapp:2

C myapp:latest

D myapp

💡 Hint

Refer to variable_tracker for BUILD_NUMBER and Docker Image Tag values.

Concept Snapshot

Jenkins builds Docker images tagged uniquely (e.g., with BUILD_NUMBER).
The image is pushed to a Docker registry.
This image acts as an artifact for deployment or later pipeline stages.
Tagging prevents overwriting previous images.
Push must succeed for artifact availability.

Full Transcript

This visual execution shows how Jenkins builds a Docker image as an artifact. The pipeline starts by checking out code, then builds a Docker image tagged with the build number. The image is stored locally and then pushed to a Docker registry. Once pushed, the image is available as an artifact for deployment or further pipeline steps. Tagging with the build number ensures each image is unique. If pushing fails, the image is not available remotely. This process helps manage Docker images reliably in CI/CD pipelines.