Trigger a Kubernetes Deployment from a Dockerhub Push Event

Learn how to trigger a Kubernetes deployment when an image is updated

In this example, we will cover how to trigger a Kubernetes deployment from a Dockerhub Push event using a Dockerhub registry trigger.

Our example will have two pipelines. One that is responsible for packaging code (CI), and the other will be responsible for deploying code (CD).

Prerequisites

A free Codefresh account
A DockerHub registry connected to your Codefresh account
A Kubernetes cluster connected to your Codefresh account
A service for your application deployed to your cluster

The Example Project

You can see the example project on GitHub. The repository contains a simple Hello World NodeJs app as well as 2 pipelines.

Create the CI Pipeline

As mentioned before, our first pipeline will handle the CI process. There will be 3 stages:

A stage for cloning
A stage for building the image
A stage for pushing the image to DockerHub

codefresh-CI-pipeline.yml

version: '1.0'

stages:
- checkout
- build
- push

steps:
  clone:
    title: Cloning main repository...
    type: git-clone
    stage: checkout
    arguments:
      repo: 'codefresh-contrib/registry-trigger-sample-app'
      revision: 'master'
      git: github
  build_my_app:
    title: Building image...
    type: build
    stage: build
    arguments:
      image_name: registry-trigger-sample-app
      working_directory: ${{clone}}
      tag: 'master'
      dockerfile: Dockerfile
  push_to_my_registry:
    stage: 'push'
    type: push
    title: Pushing to Dockerhub...
    arguments:
      candidate: ${{build_my_app}}
      tag: 'latest'
      registry: dockerhub
      image_name: annabaker/registry-trigger-sample-app

This pipeline does the following:

Clones the source code with a Git clone step
Builds a docker image tagged with the Application version using a build step
Pushes the Docker image using a Push step to the DockerHub registry you have integrated with Codefresh.

Create the CD Pipeline

This pipeline will only contain one stage/step, for deploying.

Note that for the trigger mechanism to take place, you will need to add a DockerHub registry trigger to the pipeline.

codefresh-CD-pipeline.yml

version: "1.0"

stages:
  - "deploy"

steps:
  deploy_to_k8s:
    title: Running Deploy Script...
    type: deploy
    kind: kubernetes
    arguments:
      cluster: [email protected]
      namespace: default
      service: registry-trigger-sample-app
      candidate:
        image: annabaker/registry-trigger-sample-app:latest
        registry: 'dockerhub'