Kubernetes is rapidly evolving from a Docker orchestration platform to a general-purpose cloud operating system. Thanks to the operators , Kubernetes is able to initially manage the high-level concepts and business processes, which means that you no longer manage the building modules blocks, services and deployments, but instead describe the things that these building blocks can create, for example, web servers, databases data, continuous deployment, certificate management, and more.
When deployed to a Kubernetes cluster, Tekton Pipelines provides the ability to define and execute build tasks, inputs and outputs in the form of simple values or complex objects such as Docker images, and combine those resources into pipelines. These new Kubernetes resources and the controllers that manage them result in a standalone CI / CD platform hosted on a Kubernetes cluster.
In this post, we'll take a look at a simple build pipeline running on MicroK8S.
Preparing a test Kubernetes cluster
In this post, I am using MicroK8S to create a Kubernetes cluster. MicroK8S is useful here because it offers a selection of official add-ons , one of which is the Docker image registry. Since our pipeline builds a Docker image, we need to host it somewhere, and the MicroK8S registry add-in provides us with this functionality with a single command:
microk8s.enable registry
We also need to enable DNS lookup from the MicroK8S cluster. This is done by enabling the DNS add-on:
microk8s.enable dns
Installing Tekton Pipelines
Installing Tekton Pipelines is done with one command kubectl
(or microk8s.kubectl
in our case):
microk8s.kubectl apply --filename https://storage.googleapis.com/tekton-releases/pipeline/latest/release.yaml
We can now create Tekton resources in our Kubernetes cluster.
The "Hello World" task
, . , echo
Hello World
, ubuntu
.
YAML helloworldtask.yml
:
apiVersion: tekton.dev/v1alpha1 kind: Task metadata: name: echo-hello-world spec: steps: - name: echo image: ubuntu command: - echo args: - "Hello World"
Kubernetes :
microk8s.kubectl apply -f helloworldtask.yml
, , - . , Tekton .
YAML helloworldtaskrun.yml
:
apiVersion: tekton.dev/v1alpha1 kind: TaskRun metadata: name: echo-hello-world-task-run spec: taskRef: name: echo-hello-world
Kubernetes :
microk8s.kubectl apply -f helloworldtaskrun.yml
Docker
hello world, Tekton, Docker. , RandomQuotes.
. .
, , — Git, . , git, URL- , :
apiVersion: tekton.dev/v1alpha1 kind: PipelineResource metadata: name: randomquotes-git spec: type: git params: - name: revision value: master - name: url value: https://github.com/OctopusSamples/RandomQuotes-Java.git
Docker, . MicroK8S, Docker http://registry.container-registry.svc.cluster.local:5000.
image
, Docker, registry.container-registry.svc.cluster.local:5000/randomquotes
:
apiVersion: tekton.dev/v1alpha1 kind: PipelineResource metadata: name: randomquotes-image spec: type: image params: - name: url value: registry.container-registry.svc.cluster.local:5000/randomquotes
Docker, Docker .
Docker Docker . Kubernetes Docker, : Docker Docker?
, , Docker CLI , - Docker. , umoci Docker, Kaniko Buildah Docker Docker Podman Docker.
Kaniko Tekton, Docker Docker, Kubernetes. YAML :
apiVersion: tekton.dev/v1alpha1 kind: Task metadata: name: build-docker-image-from-git-source spec: inputs: resources: - name: docker-source type: git params: - name: pathToDockerFile type: string description: The path to the dockerfile to build default: /workspace/docker-source/Dockerfile - name: pathToContext type: string description: The build context used by Kaniko (https://github.com/GoogleContainerTools/kaniko#kaniko-build-contexts) default: /workspace/docker-source outputs: resources: - name: builtImage type: image steps: - name: build-and-push image: gcr.io/kaniko-project/executor:v0.17.1 # specifying DOCKER_CONFIG is required to allow kaniko to detect docker credential env: - name: "DOCKER_CONFIG" value: "/tekton/home/.docker/" command: - /kaniko/executor args: - --dockerfile=$(inputs.params.pathToDockerFile) - --destination=$(outputs.resources.builtImage.url) - --context=$(inputs.params.pathToContext)
.
, , .
git
:
inputs: resources: - name: docker-source type: git
image
:
outputs: resources: - name: builtImage type: image
, , Docker:
spec: inputs: params: - name: pathToDockerFile type: string description: The path to the dockerfile to build default: /workspace/docker-source/Dockerfile - name: pathToContext type: string description: The build context used by Kaniko (https://github.com/GoogleContainerTools/kaniko#kaniko-build-contexts) default: /workspace/docker-source
, /workspace/docker-source
— , git
, docker-source
, .
, Docker. , gcr.io/kaniko-project/executor:v0.17.1
image, Kaniko:
spec: steps: - name: build-and-push image: gcr.io/kaniko-project/executor:v0.17.1 # specifying DOCKER_CONFIG is required to allow kaniko to detect docker credential env: - name: "DOCKER_CONFIG" value: "/tekton/home/.docker/" command: - /kaniko/executor args: - --dockerfile=$(inputs.params.pathToDockerFile) - --destination=$(outputs.resources.builtImage.url) - --context=$(inputs.params.pathToContext)
, . docker-source
randomquotes-git
, builtImage — randomquotes-image
.
:
apiVersion: tekton.dev/v1alpha1 kind: TaskRun metadata: name: build-docker-image-from-git-source-task-run spec: taskRef: name: build-docker-image-from-git-source inputs: resources: - name: docker-source resourceRef: name: randomquotes-git params: - name: pathToDockerFile value: Dockerfile - name: pathToContext value: /workspace/docker-source outputs: resources: - name: builtImage resourceRef: name: randomquotes-image
Tekton CLI , kubectl
, MicroK8S microk8s.kubectl
. kubectl
— , MicroK8S kubectl
:
sudo microk8s.kubectl config view --raw > $HOME/.kube/config
:
tkn taskrun logs build-docker-image-from-git-source-task-run
Tekton?
Docker, Tekton . Docker, .
Kubernetes . , , ?
, Tekton , . tkn
CLI , kubectl
, . kubectl create -f taskrun.yml
, .
, Tekton — . Jenkins X OpenShift Pipelines — , Tekton.
Kubernetes , , , , , . , Kubernetes CI , , Kubernetes.
, Jenkins X OpenShift Pipelines, Tekton . Tekton , , , , .