Knative Build to Tekton Task — Hello World

I am starting to learn Tekton and trying to compare it with Knative Build which I started learning early this year. Here is a simple Hello World example to compare both technology. The idea is to migrate to Tekton Pipeline and convert Build and BuildTemplate YAML to task, task run, pipeline, and pipeline resource YAML because Build and BuildTemplate are being deprecated.

A simple hello world example using Knative Build:

build.yaml

Apply build.yaml

kubectl apply -f build.yaml
build.build.knative.dev/echo-hello-world created

Build Pod

kubectl logs echo-hello-world-pod-1faec3 --all-containers
{"level":"warn","ts":1560795916.6960523,"logger":"fallback-logger","caller":"logging/config.go:65","msg":"Fetch GitHub commit ID from kodata failed: \"ref: refs/heads/upstream/release-0.5\" is not a valid GitHub commit ID"}
{"level":"info","ts":1560795916.6967626,"logger":"fallback-logger","caller":"creds-init/main.go:40","msg":"Credentials initialized."}
hello world
Build successful

Kubernetes Cluster Resource List

kubectl get all
NAME                                       READY   STATUS      RESTARTS   AGE
pod/echo-hello-world-pod-1faec3            0/1     Completed   0          25m
NAME                 TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)   AGE
service/kubernetes   ClusterIP   10.96.0.1    <none>        443/TCP   4d1h
NAME                                       SUCCEEDED   REASON   STARTTIME   COMPLETIONTIME
build.build.knative.dev/echo-hello-world   True                 25m

A simple hello world example using Tekton Task:

task.yaml

Apply task.yaml

kubectl apply -f task.yaml
task.tekton.dev/echo-hello-world created

Kubernetes Cluster Resource List

kubectl get all
NAME                 TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)   AGE
service/kubernetes   ClusterIP   10.96.0.1    <none>        443/TCP   4d1h
NAME                               AGE
task.tekton.dev/echo-hello-world   15m

task-run.yaml

Apply task-run.yaml

kubectl apply -f task-run.yaml
taskrun.tekton.dev/echo-hello-world-task-run created

Kubernetes Cluster Resource List

kubectl get all
NAME                                       READY   STATUS      RESTARTS   AGE
pod/echo-hello-world-task-run-pod-578741   0/2     Completed   0          29s
NAME                 TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)   AGE
service/kubernetes   ClusterIP   10.96.0.1    <none>        443/TCP   94m
NAME                                           SUCCEEDED   REASON   STARTTIME   COMPLETIONTIME
taskrun.tekton.dev/echo-hello-world-task-run   True                 29s         10s
NAME                               AGE
task.tekton.dev/echo-hello-world   22m

Task Run Pod

kubectl logs echo-hello-world-task-run-pod-578741 --all-containers
{"level":"warn","ts":1560450406.5741897,"logger":"fallback-logger","caller":"logging/config.go:65","msg":"Fetch GitHub commit ID from kodata failed: \"ref: refs/heads/master\" is not a valid GitHub commit ID"}
{"level":"info","ts":1560450406.574541,"logger":"fallback-logger","caller":"creds-init/main.go:40","msg":"Credentials initialized."}
hello world
Build successful

Knative Build vs Tekton Pipeline

Let’s look at some key differences in creating a hello world Knative build and hello world Tekton Task.

Difference 1: API Version and Kind of API are different (of course 😃)

Both build.yaml and task.yaml have similar semantics except the apiVersion and kind.

build.yaml:

apiVersion: build.knative.dev/v1alpha1
kind: Build
...

task.yaml:

apiVersion: tekton.dev/v1alpha1
kind: Task
...

Difference 2: Single Step vs Multi Step Process

Knative build defines the work that needs to be executed and runs it vs Task defines the work and TaskRun executes it.

Knative Build:

kubectl get all
NAME                                       READY   STATUS      RESTARTS   AGE
pod/echo-hello-world-pod-1faec3            0/1     Completed   0          25m
NAME                                       SUCCEEDED   REASON   STARTTIME   COMPLETIONTIME
build.build.knative.dev/echo-hello-world   True                 25m

Task:

kubectl get all
NAME                               AGE
task.tekton.dev/echo-hello-world   15m

Task Run:

kubectl get all
NAME                                       READY   STATUS      RESTARTS   AGE
pod/echo-hello-world-task-run-pod-578741   0/2     Completed   0          29s
NAME                                           SUCCEEDED   REASON   STARTTIME   COMPLETIONTIME
taskrun.tekton.dev/echo-hello-world-task-run   True                 29s         10s
NAME                               AGE
task.tekton.dev/echo-hello-world   22m

See you with one more comparison … 👍