Simple Pipeline

Creating a basic pipeline with multiple tasks

A pipeline chains together multiple tasks to create a workflow. This example shows a simple pipeline with dependent tasks.

Example

apiVersion: tekton.dev/v1
kind: Task
metadata:
  name: add-task
spec:
  params:
    - name: first
      description: the first operand
    - name: second
      description: the second operand
  results:
    - name: sum
      description: the sum of the first and second operand
  steps:
    - name: add
      image: mirror.gcr.io/alpine
      env:
        - name: OP1
          value: $(params.first)
        - name: OP2
          value: $(params.second)
      command: ["/bin/sh", "-c"]
      args:
        - echo -n $((${OP1}+${OP2})) | tee $(results.sum.path);
---
apiVersion: tekton.dev/v1
kind: Pipeline
metadata:
  name: sum-three-pipeline
spec:
  params:
    - name: first
      description: the first operand
    - name: second
      description: the second operand
    - name: third
      description: the third operand
  tasks:
    - name: first-add
      taskRef:
        name: add-task
      params:
        - name: first
          value: $(params.first)
        - name: second
          value: $(params.second)
    - name: second-add
      taskRef:
        name: add-task
      params:
        - name: first
          value: $(tasks.first-add.results.sum)
        - name: second
          value: $(params.third)
  results:
    - name: sum
      description: the sum of all three operands
      value: $(tasks.second-add.results.sum)
    - name: partial-sum
      description: the sum of first two operands
      value: $(tasks.first-add.results.sum)
    - name: all-sum
      description: the sum of everything
      value: $(tasks.second-add.results.sum)-$(tasks.first-add.results.sum)
---
apiVersion: tekton.dev/v1
kind: PipelineRun
metadata:
  name: sum-three-pipeline-run
spec:
  pipelineRef:
    name: sum-three-pipeline
  params:
    - name: first
      value: "2"
    - name: second
      value: "10"
    - name: third
      value: "10"

How It Works

1. First Task Executes

   The first-add task runs first, adding the first two parameters (2 + 10 = 12) and emitting the result.

2. Second Task Uses First Task's Result

   The second-add task automatically waits for first-add to complete because it references its result using $(tasks.first-add.results.sum). It then adds this result to the third parameter (12 + 10 = 22).

3. Pipeline Results are Computed

   After all tasks complete, the pipeline computes its own results by referencing task results. These become available in the PipelineRun status.

Task Dependencies

Tekton automatically creates dependencies between tasks when:

• A task references another task’s result: $(tasks.TASK_NAME.results.RESULT_NAME)
• A task explicitly uses runAfter to specify ordering

In this example, second-add implicitly depends on first-add because it uses its result.

Expected Output

With the provided parameters (2, 10, 10):

• first-add outputs: 12
• second-add outputs: 22

Pipeline results:

sum: 22
partial-sum: 12
all-sum: 22-12

Key Concepts

• Pipeline: A collection of tasks that execute in a defined order
• Task References: Use taskRef to reference an existing task by name
• Implicit Dependencies: Tasks automatically wait for tasks whose results they reference
• Pipeline Results: Pipelines can aggregate results from multiple tasks
• Parameter Passing: Pipeline parameters can be passed to tasks, and task results can be passed to other tasks

Next Steps

• Learn about pipelines with parameters
• See parallel task execution