Build and push an image with Tekton

This guide shows you how to:

  1. Create a Task to clone source code from a git repository.

  2. Create a second Task to use the cloned code to build a Docker image and push it to a registry.

If you are already familiar with Tekton and just want to see the example, you can skip to the full code samples.

Prerequisites

  1. To follow this How-to you must have a Kubernetes cluster up and running and kubectl properly configured to issue commands to your cluster.

  2. Install Tekton Pipelines:

    kubectl apply --filename \
https://storage.googleapis.com/tekton-releases/pipeline/latest/release.yaml

    See the Pipelines installation documentation for other installation options and vendor specific instructions.

  3. Install the Tekton CLI, tkn, on your machine.

If this is your first time using Tekton Pipelines, we recommend that you complete the Getting Started tutorials before proceeding with this guide.

Clone the repository

Create a new Pipeline, pipeline.yaml, that uses the git clone Task to clone the source code from a git repository:

apiVersion: tekton.dev/v1beta1
kind: Pipeline
metadata:
  name: clone-build-push
spec:
  description: | 
    This pipeline clones a git repo, builds a Docker image with Kaniko and
    pushes it to a registry
  params:
  - name: repo-url
    type: string
  workspaces:
  - name: shared-data
  tasks:
  - name: fetch-source
    taskRef:
      name: git-clone
    workspaces:
    - name: output
      workspace: shared-data
    params:
    - name: url
      value: $(params.repo-url)

Then create the corresponding pipelinerun.yaml file:

apiVersion: tekton.dev/v1beta1
kind: PipelineRun
metadata:
  generateName: clone-build-push-run-
spec:
  pipelineRef:
    name: clone-build-push
  podTemplate:
    securityContext:
      fsGroup: 65532
  workspaces:
  - name: shared-data
    volumeClaimTemplate:
      spec:
        accessModes:
        - ReadWriteOnce
        resources:
          requests:
            storage: 1Gi
  params:
  - name: repo-url
    value: https://github.com/google/docsy-example.git

For this how-to we are using a public repository as an example. You can also use git clone with private repositories, using SSH authentication.

Build the container image with Kaniko

To build the image use the Kaniko Task from the community hub.

  1. Add the image reference to the params section in pipeline.yaml:

    params: 
- name: image-reference
  type: string

    This parameter is used to add the tag corresponding the container registry where you are going to push the image.

  2. Create the new build-push Task in the same pipeline.yaml file:

    tasks:
...
  - name: build-push
    runAfter: ["fetch-source"]
    taskRef:
      name: kaniko
    workspaces:
    - name: source
      workspace: shared-data
    params:
    - name: IMAGE
      value: $(params.image-reference)

    This new Task refers to kaniko, which is going to be installed from the community hub. A Task has its own set of workspaces and params passed down from the parameters and Workspaces defined at Pipeline level. In this case, the Workspace source and the value of IMAGE. Check the kaniko Task documentation to see all the available options.

  3. Instantiate the build-push Task. Add the value of image-reference to the params section in pipelinerun.yaml:

    params:
- name: image-reference
  value: container.registry.com/sublocation/my_app:version

    Replace container.registry.com/sublocation/my_app:version with the actual tag for your registry. You can set up a local registry for testing purposes.

Check the full code samples to see how all the pieces fit together.

Container registry authentication

In most cases, to push the image to a container registry you must provide authentication credentials first.

  1. Set up authentication with the Docker credential helper and generate the Docker configuration file, $HOME/.docker/config.json, for your registry. This step is different depending on your registry.

    Check your cloud provider documentation to complete this step.

  2. Create a Kubernetes Secret, docker-credentials.yaml with your credentials:

    apiVersion: v1
kind: Secret
metadata:
  name: docker-credentials
data:
  config.json: efuJAmF1...

    The value of config.json is the base64-encoded ~/.docker/config.json file. You can get this data with the following command:

    cat ~/.docker/config.json | base64 -w0

  3. Update pipeline.yaml and add a Workspace to mount the credentials directory:

    At the Pipeline level:

    workspaces:
- name: docker-credentials

    And under the build-push Task:

    workspaces:
- name: dockerconfig
  workspace: docker-credentials

  4. Instantiate the new docker-credentials Workspace in your pipelinerun.yaml file by adding a new entry under workspaces:

    - name: docker-credentials
  secret:
    secretName: docker-credentials

See the complete files in the full code samples section.

Run your Pipeline

You are ready to install the Tasks and run the pipeline.

  1. Install the git-clone and kaniko Tasks:

    tkn hub install task git-clone
tkn hub install task kaniko

  2. Apply the Secret with your Docker credentials.

    kubectl apply -f docker-credentials.yaml

  3. Apply the Pipeline:

    kubectl apply -f pipeline.yaml

  4. Create the PipelineRun:

    kubectl create -f pipelinerun.yaml

    This creates a PipelineRun with a unique name each time:

    pipelinerun.tekton.dev/clone-build-push-run-4kgjr created

  5. Use the PipelineRun name from the output of the previous step to monitor the Pipeline execution:

    tkn pipelinerun logs  clone-build-push-run-4kgjr -f

    After a few seconds, the output confirms that the image was built and pushed successfully:

    [fetch-source : clone] + '[' false '=' true ]
[fetch-source : clone] + '[' false '=' true ]
[fetch-source : clone] + '[' false '=' true ]
[fetch-source : clone] + CHECKOUT_DIR=/workspace/output/
[fetch-source : clone] + '[' true '=' true ]
[fetch-source : clone] + cleandir
[fetch-source : clone] + '[' -d /workspace/output/ ]
[fetch-source : clone] + rm -rf '/workspace/output//*'
[fetch-source : clone] + rm -rf '/workspace/output//.[!.]*'
[fetch-source : clone] + rm -rf '/workspace/output//..?*'
[fetch-source : clone] + test -z 
[fetch-source : clone] + test -z 
[fetch-source : clone] + test -z 
[fetch-source : clone] + /ko-app/git-init '-url=https://github.com/google/docsy-example.git' '-revision=' '-refspec=' '-path=/workspace/output/' '-sslVerify=true' '-submodules=true' '-depth=1' '-sparseCheckoutDirectories='
[fetch-source : clone] {"level":"info","ts":1654637310.4419358,"caller":"git/git.go:170","msg":"Successfully cloned https://github.com/google/docsy-example.git @ 1c7f7e300c90cd690ca5be66b43fe58713bb21c9 (grafted, HEAD) in path /workspace/output/"}
[fetch-source : clone] {"level":"info","ts":1654637320.384655,"caller":"git/git.go:208","msg":"Successfully initialized and updated submodules in path /workspace/output/"}
[fetch-source : clone] + cd /workspace/output/
[fetch-source : clone] + git rev-parse HEAD
[fetch-source : clone] + RESULT_SHA=1c7f7e300c90cd690ca5be66b43fe58713bb21c9
[fetch-source : clone] + EXIT_CODE=0
[fetch-source : clone] + '[' 0 '!=' 0 ]
[fetch-source : clone] + printf '%s' 1c7f7e300c90cd690ca5be66b43fe58713bb21c9
[fetch-source : clone] + printf '%s' https://github.com/google/docsy-example.git

[build-push : build-and-push] WARN
[build-push : build-and-push] User provided docker configuration exists at /kaniko/.docker/config.json 
[build-push : build-and-push] INFO Retrieving image manifest klakegg/hugo:ext-alpine 
[build-push : build-and-push] INFO Retrieving image klakegg/hugo:ext-alpine from registry index.docker.io 
[build-push : build-and-push] INFO Built cross stage deps: map[]                
[build-push : build-and-push] INFO Retrieving image manifest klakegg/hugo:ext-alpine 
[build-push : build-and-push] INFO Returning cached image manifest              
[build-push : build-and-push] INFO Executing 0 build triggers                   
[build-push : build-and-push] INFO Unpacking rootfs as cmd RUN apk add git requires it. 
[build-push : build-and-push] INFO RUN apk add git                              
[build-push : build-and-push] INFO Taking snapshot of full filesystem...        
[build-push : build-and-push] INFO cmd: /bin/sh                                 
[build-push : build-and-push] INFO args: [-c apk add git]                       
[build-push : build-and-push] INFO Running: [/bin/sh -c apk add git]            
[build-push : build-and-push] fetch https://dl-cdn.alpinelinux.org/alpine/v3.14/main/x86_64/APKINDEX.tar.gz
[build-push : build-and-push] fetch https://dl-cdn.alpinelinux.org/alpine/v3.14/community/x86_64/APKINDEX.tar.gz
[build-push : build-and-push] OK: 76 MiB in 41 packages
[build-push : build-and-push] INFO[0012] Taking snapshot of full filesystem...        
[build-push : build-and-push] INFO[0013] Pushing image to us-east1-docker.pkg.dev/tekton-tests/tektonstuff/docsy:v1 
[build-push : build-and-push] INFO[0029] Pushed image to 1 destinations               

[build-push : write-url] us-east1-docker.pkg.dev/my-tekton-tests/tekton-samples/docsy:v1

Full code samples

The Pipeline:

apiVersion: tekton.dev/v1beta1
kind: Pipeline
metadata:
  name: clone-build-push
spec:
  description: |
    This pipeline clones a git repo, builds a Docker image with Kaniko and
    pushes it to a registry    
  params:
  - name: repo-url
    type: string
  - name: image-reference
    type: string
  workspaces:
  - name: shared-data
  - name: docker-credentials
  tasks:
  - name: fetch-source
    taskRef:
      name: git-clone
    workspaces:
    - name: output
      workspace: shared-data
    params:
    - name: url
      value: $(params.repo-url)
  - name: build-push
    runAfter: ["fetch-source"]
    taskRef:
      name: kaniko
    workspaces:
    - name: source
      workspace: shared-data
    - name: dockerconfig
      workspace: docker-credentials
    params:
    - name: IMAGE
      value: $(params.image-reference)

The PipelineRun:

apiVersion: tekton.dev/v1beta1
kind: PipelineRun
metadata:
  generateName: clone-build-push-run-
spec:
  pipelineRef:
    name: clone-build-push
  podTemplate:
    securityContext:
      fsGroup: 65532
  workspaces:
  - name: shared-data
    volumeClaimTemplate:
      spec:
        accessModes:
        - ReadWriteOnce
        resources:
          requests:
            storage: 1Gi
  - name: docker-credentials
    secret:
      secretName: docker-credentials
  params:
  - name: repo-url
    value: https://github.com/google/docsy-example.git
  - name: image-reference
    value: container.registry.com/sublocation/my_app:version

The Docker credentials Kubernetes Secret:

apiVersion: v1
kind: Secret
metadata:
  name: docker-credentials
data:
  config.json: efuJAmF1...

Use your credentials as the value of the data field. Check the registry authentication section for more information

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