Kubernetes CRD & controller for building a website in one step

Goal

Inspired by the implementation of website controller of Kubernetes in Action , You can easily build up a website via a git repo and nginx /w kubernetes workload.

You can find more via the blog:

• 中文版：https://davidlovezoe.club/wordpress/archives/690
• English: TODO

Development

1. Define your own crd(CustomResourceDefinitions) struct, for example:

   type Website struct {
       metav1.TypeMeta   `json:",inline"`
       metav1.ObjectMeta `json:"metadata,omitempty"`
   
       Spec   WebsiteSpec   `json:"spec"`
       Status WebsiteStatus `json:"status"`
   }
   
   type WebsiteSpec struct {
       GitRepo        string `json:"gitRepo"`
       DeploymentName string `json:"deploymentName"`
       Replicas       *int32 `json:"replicas"`
   }
   
   type WebsiteStatus struct {
       AvailableReplicas int32 `json:"availableReplicas"`
   }
   
   type WebsiteList struct {
       metav1.TypeMeta `json:",inline"`
       metav1.ListMeta `json:"metadata,omitempty"`
   
       Items []Website `json:"items"`
   }

2. Generate the controller stuff, not write it

   The kubernetes community provides serveral ways to automatically generate the controller stuff, like:

   • Code generator
   • Kubebuilder
   • Operator-sdk

   I use code generator for this project and wrap it as a shell script codegen.sh:

   ./vendor/k8s.io/code-generator/generate-groups.sh "deepcopy,client,informer,lister" \
   github.com/nevermosby/my-crd-controller/pkg/client \
   github.com/nevermosby/my-crd-controller/pkg/apis "mycontroller:v1alpha1" \
   --go-header-file /Users/davidli/gh/myk8scrd/src/github.com/nevermosby/my-crd-controller/hack/custom-boilerplate.go.txt

3. Write your event handler

   • Create the nginx deployment based on the git repo
   • Create the nodeport service based on the nginx deployment

Deploy the CRD and controller

1. Deploy the CRD via YAML
2. Deploy the controller via deployment