My First Task

Let's go straight to our hello world! Like everything in kubernetes it's a manifest so let's develop our manifest for a hello world task.

Everything stays as always in kubernetes...

# --- STANDARD BLOCK
apiVersion: tekton.dev/v1beta1
kind: Task
metadata:
  name: hello-task
spec: # Here we will define what we want
# ---

cat <<EOF > taskHW.yaml
apiVersion: tekton.dev/v1beta1
kind: Task
metadata:
  name: hello-task
spec:
  steps: # Our list of steps
  - name: hello
    image: ubuntu
    script: >
      echo "Hello World"
EOF

kubectl create -f taskHW.yaml
task.tekton.dev/hello-task created

kubectl get tasks
NAME         AGE
hello-task   4s

kubectl get tasks -n tekton-pipelines
No resources found in tekton-pipelines namespace.

kubectl describe task hello-task
Name:         hello-task
Namespace:    default
Labels:       <none>
Annotations:  <none>
API Version:  tekton.dev/v1
Kind:         Task
Metadata:
  Creation Timestamp:  2024-07-31T11:24:23Z
  Generation:          1
  Resource Version:    1995385
  UID:                 8f1b52d9-b2a1-4df4-8b7a-1d3ee1c898c1
Spec:
  Steps:
    Compute Resources:
    Image:   ubuntu
    Name:    hello
    Script:  echo "Hello World"

Events:  <none>

As we didn't define the namespace it was created in default and we can observe that Tekton separates these resources by namespace.

This is just the definition of a task but to actually run a task you need a taskRun.

cat <<EOF > taskRunHW.yaml
apiVersion: tekton.dev/v1beta1
kind: TaskRun
metadata:
  # In this case we are declaring a prefix for it to generate the name
  generateName: hello-task-
spec:
  taskRef:
    name: hello-task # Which task will be executed
EOF

kubectl create -f taskRunHW.yaml
taskrun.tekton.dev/hello-task-46z7v created

kubectl get taskruns
NAME               SUCCEEDED   REASON      STARTTIME   COMPLETIONTIME
hello-task-46z7v   True        Succeeded   49s         31s

kubectl logs hello-task-46z7v-pod
Defaulted container "step-hello" out of: step-hello, prepare (init), place-scripts (init)
Hello World

Let's create with one more step to test what we have.

cat <<EOF > taskHW2.yaml
apiVersion: tekton.dev/v1beta1
kind: Task
metadata:
  name: hello-task2
spec:
  steps:
  - name: hello
    image: ubuntu
    script: >
      echo "Hello World"
  - name: world
    image: ubuntu
    script: >
      echo "World hello"
EOF

kubectl create -f taskHW2.yaml
task.tekton.dev/hello-task2 created

kubectl get tasks
hello-task    19m
hello-task2   3s

cat <<EOF > taskRunHW2.yaml
apiVersion: tekton.dev/v1beta1
kind: TaskRun
metadata:
  generateName: hello-task2-
spec:
  taskRef:
    name: hello-task2
EOF

kubectl create -f taskRunHW2.yaml
taskrun.tekton.dev/hello-task2-fg8gh created

kubectl logs hello-task2-fg8gh-pod
Defaulted container "step-hello" out of: step-hello, step-world, prepare (init), place-scripts (init)
Hello World

# Notice in the output above that it brought the log of the first step because we didn't pass which step.
# Passing the step we want the log from
kubectl logs hello-task2-fg8gh-pod step-hello
Hello World

kubectl logs hello-task2-fg8gh-pod step-world
World hello

The Tekton cli actually comes as a facilitator that applies filters to the kubectl command.

tkn task list
NAME          DESCRIPTION   AGE
hello-task                  1 hour ago
hello-task2                 1 hour ago

kubectl get task
NAME          AGE
hello-task    103m
hello-task2   83m

tkn task describe hello-task
Name:        hello-task
Namespace:   default

🦶 Steps

 ∙ hello

🗂  Taskruns

NAME                         STARTED          DURATION   STATUS
hello-pipeline-q5c4f-hello   14 minutes ago   9s         Succeeded
hello-task-46z7v             1 hour ago       18s        Succeeded

kubectl describe task hello-task
Name:         hello-task
Namespace:    default
Labels:       <none>
Annotations:  <none>
API Version:  tekton.dev/v1
Kind:         Task
Metadata:
  Creation Timestamp:  2024-07-31T11:24:23Z
  Generation:          1
  Resource Version:    1995385
  UID:                 8f1b52d9-b2a1-4df4-8b7a-1d3ee1c898c1
Spec:
  Steps:
    Compute Resources:
    Image:   ubuntu
    Name:    hello
    Script:  echo "Hello World"

Events:  <none>