What’s in a basic project?

When scaffolding out a new project, Kubebuilder provides us with a few basic pieces of boilerplate.

Build Infrastructure

First up, basic infrastructure for building your project:

`go.mod`: A new Go module matching our project, with basic dependencies

module tutorial.kubebuilder.io/project

go 1.15

require (
	github.com/go-logr/logr v0.3.0
	github.com/onsi/ginkgo v1.14.1
	github.com/onsi/gomega v1.10.2
	github.com/robfig/cron v1.2.0
	k8s.io/api v0.19.2
	k8s.io/apimachinery v0.19.2
	k8s.io/client-go v0.19.2
	sigs.k8s.io/controller-runtime v0.7.0
)

`Makefile`: Make targets for building and deploying your controller


# Image URL to use all building/pushing image targets
IMG ?= controller:latest
# Produce CRDs that work back to Kubernetes 1.11 (no version conversion)
CRD_OPTIONS ?= "crd:trivialVersions=true,preserveUnknownFields=false"

# Get the currently used golang install path (in GOPATH/bin, unless GOBIN is set)
ifeq (,$(shell go env GOBIN))
GOBIN=$(shell go env GOPATH)/bin
else
GOBIN=$(shell go env GOBIN)
endif

all: manager

# Run tests
ENVTEST_ASSETS_DIR=$(shell pwd)/testbin
test: generate fmt vet manifests
	mkdir -p ${ENVTEST_ASSETS_DIR}
	test -f ${ENVTEST_ASSETS_DIR}/setup-envtest.sh || curl -sSLo ${ENVTEST_ASSETS_DIR}/setup-envtest.sh https://raw.githubusercontent.com/kubernetes-sigs/controller-runtime/v0.7.0/hack/setup-envtest.sh
	source ${ENVTEST_ASSETS_DIR}/setup-envtest.sh; fetch_envtest_tools $(ENVTEST_ASSETS_DIR); setup_envtest_env $(ENVTEST_ASSETS_DIR); go test ./... -coverprofile cover.out

# Build manager binary
manager: generate fmt vet
	go build -o bin/manager main.go

# Run against the configured Kubernetes cluster in ~/.kube/config
run: generate fmt vet manifests
	go run ./main.go

# Install CRDs into a cluster
install: manifests kustomize
	$(KUSTOMIZE) build config/crd | kubectl apply -f -

# Uninstall CRDs from a cluster
uninstall: manifests kustomize
	$(KUSTOMIZE) build config/crd | kubectl delete -f -

# Deploy controller in the configured Kubernetes cluster in ~/.kube/config
deploy: manifests kustomize
	cd config/manager && $(KUSTOMIZE) edit set image controller=${IMG}
	$(KUSTOMIZE) build config/default | kubectl apply -f -

# UnDeploy controller from the configured Kubernetes cluster in ~/.kube/config
undeploy:
	$(KUSTOMIZE) build config/default | kubectl delete -f -

# Generate manifests e.g. CRD, RBAC etc.
manifests: controller-gen
	$(CONTROLLER_GEN) $(CRD_OPTIONS) rbac:roleName=manager-role webhook paths="./..." output:crd:artifacts:config=config/crd/bases

# Run go fmt against code
fmt:
	go fmt ./...

# Run go vet against code
vet:
	go vet ./...

# Generate code
generate: controller-gen
	$(CONTROLLER_GEN) object:headerFile="hack/boilerplate.go.txt" paths="./..."

# Build the docker image
docker-build: test
	docker build -t ${IMG} .

# Push the docker image
docker-push:
	docker push ${IMG}

# Download controller-gen locally if necessary
CONTROLLER_GEN = $(shell pwd)/bin/controller-gen
controller-gen:
	$(call go-get-tool,$(CONTROLLER_GEN),sigs.k8s.io/controller-tools/cmd/controller-gen@v0.4.1)

# Download kustomize locally if necessary
KUSTOMIZE = $(shell pwd)/bin/kustomize
kustomize:
	$(call go-get-tool,$(KUSTOMIZE),sigs.k8s.io/kustomize/kustomize/v3@v3.8.7)

# go-get-tool will 'go get' any package $2 and install it to $1.
PROJECT_DIR := $(shell dirname $(abspath $(lastword $(MAKEFILE_LIST))))
define go-get-tool
@[ -f $(1) ] || { \
set -e ;\
TMP_DIR=$$(mktemp -d) ;\
cd $$TMP_DIR ;\
go mod init tmp ;\
echo "Downloading $(2)" ;\
GOBIN=$(PROJECT_DIR)/bin go get $(2) ;\
rm -rf $$TMP_DIR ;\
}
endef

`PROJECT`: Kubebuilder metadata for scaffolding new components

domain: tutorial.kubebuilder.io
layout: go.kubebuilder.io/v3
projectName: project
repo: tutorial.kubebuilder.io/project
resources:
- api:
    crdVersion: v1
  group: batch
  kind: CronJob
  version: v1
  webhooks:
    webhookVersion: v1
version: 3-alpha

We also get launch configurations under the config/ directory. Right now, it just contains Kustomize YAML definitions required to launch our controller on a cluster, but once we get started writing our controller, it’ll also hold our CustomResourceDefinitions, RBAC configuration, and WebhookConfigurations.

config/default contains a Kustomize base for launching the controller in a standard configuration.

Each other directory contains a different piece of configuration, refactored out into its own base:

config/manager: launch your controllers as pods in the cluster
config/rbac: permissions required to run your controllers under their own service account

The Entrypoint

Last, but certainly not least, Kubebuilder scaffolds out the basic entrypoint of our project: main.go. Let’s take a look at that next...

Black lives matter.

What’s in a basic project?

Build Infrastructure

Launch Configuration

The Entrypoint