「Kubernetes 官方示例：使用 Redis 部署 PHP 留言板應用程序」Operator 化。
源碼倉庫：https://github.com/jxlwqq/guestbook-operator
前置條件
- 安裝 Docker Desktop，並啟動內置的 Kubernetes 集群
- 注冊一個 hub.docker.com 賬戶，需要將本地構建好的鏡像推送至公開倉庫中
- 安裝 operator SDK CLI:
brew install operator-sdk - 安裝 Go:
brew install go
本示例推薦的依賴版本：
- Docker Desktop: >= 4.0.0
- Kubernetes: >= 1.21.4
- Operator-SDK: >= 1.11.0
- Go: >= 1.17
jxlwqq 為筆者的 ID，命令行和代碼中涉及的個人 ID，均需要替換為讀者自己的，包括
--domain=--repo=//+kubebuilder:rbac:groups=IMAGE_TAG_BASE ?=
創建項目
使用 Operator SDK CLI 創建名為 guestbook-operator 的項目。
mkdir -p $HOME/projects/guestbook-operator
cd $HOME/projects/guestbook-operator
go env -w GOPROXY=https://goproxy.cn,direct
```shell
operator-sdk init \
--domain=jxlwqq.github.io \
--repo=github.com/jxlwqq/guestbook-operator \
--skip-go-version-check
創建 API 和控制器
使用 Operator SDK CLI 創建自定義資源定義（CRD）API 和控制器。
運行以下命令創建帶有組 app、版本 v1alpha1 和種類 Guestbook 的 API：
operator-sdk create api \
--resource=true \
--controller=true \
--group=app \
--version=v1alpha1 \
--kind=Guestbook
定義 Guestbook 自定義資源（CR）的 API。
修改 api/v1alpha1/guestbook_types.go 中的 Go 類型定義，使其具有以下 spec 和 status
type GuestbookSpec struct {
FrontendSize int32 `json:"frontendSize"`
RedisFollowerSize int32 `json:"redisFollowerSize"`
}
為資源類型更新生成的代碼：
make generate
運行以下命令以生成和更新 CRD 清單：
make manifests
實現控制器
由於邏輯較為復雜，代碼較為龐大，所以無法在此全部展示，完整的操作器代碼請參見 controllers 目錄。
在本例中，將生成的控制器文件 controllers/guestbook_controller.go 替換為以下示例實現：
/*
Copyright 2021.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package controllers
import (
"context"
appsv1 "k8s.io/api/apps/v1"
corev1 "k8s.io/api/core/v1"
"k8s.io/apimachinery/pkg/api/errors"
"k8s.io/apimachinery/pkg/runtime"
ctrl "sigs.k8s.io/controller-runtime"
"sigs.k8s.io/controller-runtime/pkg/client"
"sigs.k8s.io/controller-runtime/pkg/log"
appv1alpha1 "github.com/jxlwqq/guestbook-operator/api/v1alpha1"
)
// GuestbookReconciler reconciles a Guestbook object
type GuestbookReconciler struct {
client.Client
Scheme *runtime.Scheme
}
//+kubebuilder:rbac:groups=app.jxlwqq.github.io,resources=guestbooks,verbs=get;list;watch;create;update;patch;delete
//+kubebuilder:rbac:groups=app.jxlwqq.github.io,resources=guestbooks/status,verbs=get;update;patch
//+kubebuilder:rbac:groups=app.jxlwqq.github.io,resources=guestbooks/finalizers,verbs=update
//+kubebuilder:rbac:groups=apps,resources=deployments,verbs=get;list;watch;create;update;patch;delete
//+kubebuilder:rbac:groups=core,resources=service,verbs=get;list;watch;create;update;patch;delete
//+kubebuilder:rbac:groups=core,resources=pods,verbs=get;list;watch
// Reconcile is part of the main kubernetes reconciliation loop which aims to
// move the current state of the cluster closer to the desired state.
// TODO(user): Modify the Reconcile function to compare the state specified by
// the Guestbook object against the actual cluster state, and then
// perform operations to make the cluster state reflect the state specified by
// the user.
//
// For more details, check Reconcile and its Result here:
// - https://pkg.go.dev/sigs.k8s.io/controller-runtime@v0.9.2/pkg/reconcile
func (r *GuestbookReconciler) Reconcile(ctx context.Context, req ctrl.Request) (ctrl.Result, error) {
reqLogger := log.FromContext(ctx)
reqLogger.Info("Reconciling Guestbook")
guestbook := &appv1alpha1.Guestbook{}
err := r.Client.Get(context.TODO(), req.NamespacedName, guestbook)
if err != nil {
if errors.IsNotFound(err) {
return ctrl.Result{}, nil
}
return ctrl.Result{}, err
}
var result = &ctrl.Result{}
result, err = r.ensureDeployment(r.redisLeaderDeployment(guestbook))
if result != nil {
return *result, err
}
result, err = r.ensureService(r.redisLeaderService(guestbook))
if result != nil {
return *result, err
}
result, err = r.ensureDeployment(r.redisFollowerDeployment(guestbook))
if result != nil {
return *result, err
}
result, err = r.ensureService(r.redisFollowerService(guestbook))
if result != nil {
return *result, err
}
result, err = r.handleRedisFollowerChanges(guestbook)
if result != nil {
return *result, err
}
result, err = r.ensureDeployment(r.frontendDeployment(guestbook))
if result != nil {
return *result, err
}
result, err = r.ensureService(r.frontendService(guestbook))
if result != nil {
return *result, err
}
result, err = r.handleFrontendChanges(guestbook)
if result != nil {
return *result, err
}
return ctrl.Result{}, nil
}
// SetupWithManager sets up the controller with the Manager.
func (r *GuestbookReconciler) SetupWithManager(mgr ctrl.Manager) error {
return ctrl.NewControllerManagedBy(mgr).
For(&appv1alpha1.Guestbook{}).
Owns(&appsv1.Deployment{}).
Owns(&corev1.Service{}).
Complete(r)
}
運行以下命令以生成和更新 CRD 清單：
make manifests
運行 Operator
捆綁 Operator，並使用 Operator Lifecycle Manager（OLM）在集群中部署。
修改 Makefile 中 IMAGE_TAG_BASE 和 IMG：
IMAGE_TAG_BASE ?= docker.io/jxlwqq/guestbook-operator
IMG ?= $(IMAGE_TAG_BASE):latest
構建鏡像：
make docker-build
將鏡像推送到鏡像倉庫：
make docker-push
成功后訪問：https://hub.docker.com/r/jxlwqq/guestbook-operator
運行 make bundle 命令創建 Operator 捆綁包清單，並依次填入名稱、作者等必要信息:
make bundle
構建捆綁包鏡像：
make bundle-build
推送捆綁包鏡像：
make bundle-push
成功后訪問：https://hub.docker.com/r/jxlwqq/guestbook-operator-bundle
使用 Operator Lifecycle Manager 部署 Operator:
# 切換至本地集群
kubectl config use-context docker-desktop
# 安裝 olm
operator-sdk olm install
# 使用 Operator SDK 中的 OLM 集成在集群中運行 Operator
operator-sdk run bundle docker.io/jxlwqq/guestbook-operator-bundle:v0.0.1
創建自定義資源
編輯 config/samples/app_v1alpha1_guestbook.yaml 上的 Guestbook CR 清單示例，使其包含以下規格：
apiVersion: app.jxlwqq.github.io/v1alpha1
kind: Guestbook
metadata:
name: guestbook-sample
spec:
# Add fields here
frontendSize: 2
redisFollowerSize: 2
創建 CR：
kubectl apply -f config/samples/app_v1alpha1_guestbook.yaml
查看 Pod：
NAME READY STATUS RESTARTS AGE
frontend-85595f5bf9-jrcp4 1/1 Running 0 9s
frontend-85595f5bf9-q8fkl 1/1 Running 0 9s
redis-follower-76c5cc5b79-fxxlq 1/1 Running 0 9s
redis-follower-76c5cc5b79-g8vnf 1/1 Running 0 9s
redis-leader-6666df964-vjhp2 1/1 Running 0 9s
查看 Service：
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
frontend NodePort 10.106.145.169 <none> 80:30693/TCP 24s
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 4m58s
redis-follower ClusterIP 10.108.30.112 <none> 6379/TCP 24s
redis-leader ClusterIP 10.106.255.152 <none> 6379/TCP 24s
瀏覽器訪問：http://localhost:30693
網頁上會顯示出 Guestbook 的表單頁面。
更新 CR：
# 修改frontend 和 redis 副本數
kubectl patch guestbook guestbook-sample -p '{"spec":{"frontendSize": 3, "redisFollowerSize": 3}}' --type=merge
查看 Pod：
NAME READY STATUS RESTARTS AGE
frontend-85595f5bf9-4pmfj 1/1 Running 0 4s
frontend-85595f5bf9-jrcp4 1/1 Running 0 50s
frontend-85595f5bf9-q8fkl 1/1 Running 0 50s
redis-follower-76c5cc5b79-bxbb4 1/1 Running 0 4s
redis-follower-76c5cc5b79-fxxlq 1/1 Running 0 50s
redis-follower-76c5cc5b79-g8vnf 1/1 Running 0 50s
redis-leader-6666df964-vjhp2 1/1 Running 0 50s
做好清理
operator-sdk cleanup guestbook-operator
operator-sdk olm uninstall