Getting Started with Resolvers

Introduction

This guide will take you from an empty Kubernetes cluster to a functioning Tekton Pipelines installation and a PipelineRun executing with a Pipeline stored in a git repo.

Prerequisites

  • A computer with kubectl.
  • A Kubernetes cluster running at least Kubernetes 1.24. A kind cluster should work fine for following the guide on your local machine.
  • An image registry that you can push images to. If you’re using kind make sure your KO_DOCKER_REPO environment variable is set to kind.local.
  • A publicly available git repository where you can put a pipeline yaml file.

Step 1: Install Tekton Pipelines and the Resolvers

See the installation instructions for Tekton Pipeline, and the installation instructions for the built-in resolvers.

Step 2: Ensure Pipelines is configured to enable resolvers

Starting with v0.41.0, remote resolvers for Tekton Pipelines are enabled by default, but can be disabled via feature flags in the resolvers-feature-flags configmap in the tekton-pipelines-resolvers namespace. Check that configmap to verify that the resolvers you wish to have enabled are set to "true".

The feature flags for the built-in resolvers are:

  • The bundles resolver: enable-bundles-resolver
  • The git resolver: enable-git-resolver
  • The hub resolver: enable-hub-resolver
  • The cluster resolver: enable-cluster-resolver

Step 3: Try it out!

In order to test out your install you’ll need a Pipeline stored in a public git repository. First cd into a clone of your repo and then create a new branch:

# checkout a new branch in the public repo you're using
git checkout -b add-a-simple-pipeline

Then create a basic pipeline:

cat <<"EOF" > pipeline.yaml
kind: Pipeline
apiVersion: tekton.dev/v1beta1
metadata:
  name: a-simple-pipeline
spec:
  params:
  - name: username
  tasks:
  - name: task-1
    params:
    - name: username
      value: $(params.username)
    taskSpec:
      params:
      - name: username
      steps:
      - image: alpine:3.15
        script: |
          echo "hello $(params.username)"
EOF

Commit the pipeline and push it to your git repo:

git add ./pipeline.yaml
git commit -m "Add a basic pipeline to test Tekton Pipeline remote resolution"

# push to your publicly accessible repository, replacing origin with
# your git remote's name
git push origin add-a-simple-pipeline

And finally create a PipelineRun that uses your pipeline:

# first assign your public repo's url to an environment variable
REPO_URL=# insert your repo's url here

# create a pipelinerun yaml file
cat <<EOF > pipelinerun.yaml
kind: PipelineRun
apiVersion: tekton.dev/v1beta1
metadata:
  name: run-basic-pipeline-from-git
spec:
  pipelineRef:
    resolver: git
    params:
    - name: url
      value: ${REPO_URL}
    - name: revision
      value: add-a-simple-pipeline
    - name: pathInRepo
      value: pipeline.yaml
  params:
  - name: username
    value: liza
EOF

# execute the pipelinerun
kubectl apply -f ./pipelinerun.yaml

Step 6: Monitor the PipelineRun

First let’s watch the PipelineRun to see if it succeeds:

kubectl get pipelineruns -w

Shortly the PipelineRun should move into a Succeeded state.

Now we can check the logs of the PipelineRun’s only task:

kubectl logs run-basic-pipeline-from-git-task-1-pod
# This should print "hello liza"

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