Escribir un operador de Kubernetes desde cero

En este artículo, analizaremos más de cerca cómo crear su propio operador de Kubernetes desde cero. Los operadores son complementos que utilizan recursos personalizados (tipo) para administrar aplicaciones. Leer más en la documentación oficial .

— HelloApp. HelloApp, Kubernetes.

kind: HelloApp — (Custom Resource Definition, CRD), ( ). ( ).

, , Go. .

() , Kubernetes API.

Kubernetes:

Kubernetes — . API ( API). , , API Kubernetes . . . Go — Kubernetes, , .

:

1. Go lang (1.16)
2. Operator SDK (1.5)
3. Kind
4. Visual Studio Code Go

:

1:

2:

3: CRD

4: CRD

5:

6:

7:

1:

, Operator SDK. Operator SDK 1.5. SDK, . .

$ mkdir demo-operator
$ cd demo-operator
$ operator-sdk init --domain anupam.com --repo 
github.com/anupamgogoi/demo-operator
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    

API

$ operator-sdk create api --group apps --version v1 --kind HelloApp --resource --controller
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    

.

:

1. Makefile , , . make help, .
2. . , .
3. . .
4. .
5. , . .

2:

. CRD (), () kind HelloApp , spec.size.

. spec : image () size (). spec, [4] .

. . — HelloApp , . , spec.size, — . . API .

Reconciler, Reconcile. Reconcile , CRUD (create read update delete — « », . ), (kind) (spec). , .

main.go

main.go Operator-SDK . , . main.go.

main.go:

ctrl.GetConfigOrDie() Kubernetes ~/.kube/config . ~/.kube/config :

IP , . . . GetConfigOrDie() , ctrl.NewManager() . API API Kubernetes. . main.go, .

kubectl CLI API API Kubernetes. :

$ kubectl get nodes --v=8
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    

3: CRD

, HelloApp . CRD. demo-operator :

$ make manifests
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    

CRD

~/demo-operator/config/crd/bases

~/demo-operator/config/samples .

4: CRD

, . kind, .

$ kind create cluster --name k8s
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    

CRD :

$ make install
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    

~/demo-operator/config/crd/bases

$ kubectl apply -f .
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    

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5:

. Kubernetes,

$ cd demo-operator
$ go run main.go
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    

:

— samples :

$ kubectl create ns test
$ kubectl apply -f apps_v1_helloapp.yaml -n test
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    

, test:

$ kubectl get all -n test
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    

:

$ kubectl get HelloApp -n test
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    

— !

6:

— , .

, -, CRD , 4 ( CRD).

, k8s . Go Visual Studio Code . Run → Start Debugging VS Code, .

— :

, ~/demo-operator/config/samples

CRD.

$ kubectl apply -f apps_v1_helloapp.yaml -n test
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    

Reconcile, Reconcile, . Reconcile. , , .

7:

— (YAML) docker- . :

1. .
2. .
3. , API Kubernetes.
4. 2.
5. , .

~/demo-operator/config/rbac . . ?

.

:

1. Get, HelloApp. , Get HelloApp, API apps.anupam.com.
2. Get, Deployment. , Deployment Kubernetes API apps.
3. Update Deployment, API apps.

, +.

//+kubebuilder:rbac:groups=apps.anupam.com,resources=helloapps,verbs=get;list;watch;create;update;patch;delete
//+kubebuilder:rbac:groups=apps,resources=deployments,verbs=get;list;watch;create;update;patch;delete
//+kubebuilder:rbac:groups=apps.anupam.com,resources=helloapps/status,verbs=get;update;patch
//+kubebuilder:rbac:groups=apps.anupam.com,resources=helloapps/finalizers,verbs=update
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    

. Kubernetes . controller-gen CLI (CRD, RBAC . .).

make manifests. , , — CRD, , . .

Docker-

— docker- Kubernetes.

, Dockerfile, Operator-SDK. .

docker-:

$ make docker-build IMG=anupamgogoi/demo-operator:latest
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    

docker. registry :

make docker-push IMG=anupamgogoi/demo-operator:latest
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    

.

dist 5 , .

1-Namespace.yaml ( ). . 2, 3 4 rbac. 5 crd/bases. , 6-Controller.yaml, . . .

.

Kubernetes CentOS. . . - Kubernetes . .

dist - , kubectl apply .

demo-operator-system. , .

. CRD. CRD — helloapps.apps.anupam.com, 5-apps.anupam.com_helloapps.yaml.

, kind, HelloApp. - , HelloApp.

, HelloApp ( ) . Kubernetes.

, HelloApp.

$ kubectl get all -n test
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    

!

, (size=1).

, IP .

. .

Kubernetes Operator-SDK. Go, . !