Container Deployment with Tekton

Mary Mbaoma's photo
Mary Mbaoma
·

4 min read

Table of contents

Container deployment is now a norm in software development. Containerization refers to steps taken to encapsulate applications with their dependencies and runtimes into lightweight, isolated units called containers.

Tekton is a cloud-native, open-source tool that facilitates and automates Continuous Integration and Continuous Deployment (CI/CD) pipelines. It is a Kubernetes-native framework for building, testing, and deploying applications efficiently and consistently.

In this article, we will configure a Tekton pipeline that builds and pushes a Docker image to DockerHub.

Understanding Tekton

Tekton can run on any Kubernetes cluster, including managed Kubernetes services like Azure Kubernetes Service (AKS). It fits into the CI/CD landscape by offering:

  • Declarative Pipelines: This implies that pipeline configurations are written as code and can be versioned allowing for easy collaboration.

  • Containerization: Tekton operates with containers, which are perfect for modern applications. It can build, test, and deploy containers, making it well-suited for container-centric CI/CD workflows.

Tekton also offers the following features and benefits:

  • Flexibility: Tekton allows users to create customized CI/CD workflows.

  • Portability: Using Tekton, users can configure pipelines that build and deploy applications consistently across multiple clusters, including on-premises and cloud environments.

Setting up our Environment

To use Tekton, we need to have a local Kubernetes cluster running either minikube or Kind; or (in my case, as a Mac user), have Docker Desktop running.

To install the latest version of Tekton Pipelines, run

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

Tekton's dashboard gives us a view of how Tekton creates resources and handles task execution and completion. To install Tekton's dashboard, run

kubectl apply --filenamehttps://storage.googleapis.com/tekton-releases/dashboard/latest/release.yaml

To access the dashboard, there are a couple of options such as proxy or port forwarding. We will use port forwarding

kubectl --namespace tekton-pipelines port-forward svc/tekton-dashboard 9097:9097

Install Tekton's CLI.

Configuring Tekton Pipelines

A pipeline consists of the following: Tasks, TaskRun, Pipelines, and PipelineRun.

  • Tekton Tasks: Contain steps that run to achieve a goal. Each task is a pod and each step in a task runs in a container. TaskRun instantiates and executes the defined Tasks.

  • Tekton Pipelines: Refers to a series of tasks defined in a specified order of execution as part of the CI/CD workflow. PipelineRun contains the value of variables in a Pipeline.

To achieve our goal, we will create a Pipeline that

  • Fetches the source code

  • Builds the image, and

  • Pushes the built image to DockerHub.

We will achieve the above steps using Kaniko, a tool used to build container images from a Dockerfile, inside a container or Kubernetes cluster.

Authenticating to DockerHub

  • Log into Docker via CLI
$ docker login
  • We create an encoded string of our docker-hub-user-name-:docker-hub-password
$ echo -n '<docker-hub-username>:<docker-hub-password>' | base64
ENCODED-STRING
  • Edit ~/.docker/config.json file
$ sudo nano ~/.docker/config.json
{ "auths": { "https://index.docker.io/v1/": { "auth": "ENCODED-STRING" } } }
  • Encode ~/.docker/config.json
$ cat ~/.docker/config.json | base64
ENCODED-JSON-FILE

Configuration Files

  • After authenticating to DockerHub, we create a YAML file to store our authentication details in.
#docker-secret.yaml
apiVersion: v1
kind: Secret
metadata:
  name: docker-credentials
data:
  config.json: ENCODED-JSON-FILE
  • The pipeline.yaml file, hold tasks which will carry out cloning, building and pushing the image to DockerHub. The tasks are defined as variables.
#pipeline.yaml
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 pipeline-runs.yaml file, this file holds the values of the variables defined in the pipeline.yaml file.
#pipeline-run.yaml
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: <git-repo-url>
  - name: image-reference
    value: <docker-hub-username>/<docker-repo>

Automating Deployment

Run the following commands, to

  • Install the Tasks,

  • Apply the pipeline, and

  • Create PipelineRun,

tkn hub install task git-clone
tkn hub install task kaniko
kubectl apply -f docker-secret.yaml
kubectl apply -f pipeline.yaml
kubectl create -f pipeline-run.yaml

Tekton Tasks

Tekton Pipelines

Note:

  • We have to manually create the docker hub repository, to push the image to.

  • The Dockerfile should be in the root directory of the git repository, else we specify the location of the Dockerfile.

Tekton has an active and growing community, which means we can find support, documentation, and a variety of pre-built tasks and resources to enhance our CI/CD workflows.

I hope you will try Tekton in your development process.

containerizationTektonDockerCI/CD