部署KEDA ScaledObject失败：PostgreSQL伸缩器失效求助

问题背景 #

在minikube环境中部署的KEDA PostgreSQL伸缩器曾正常工作，一段时间后突然失效。此前曾将targetQueryValue设为负值，后续修改为正值并重新部署ScaledObject后，仍无法正常运行。

相关配置与信息 #

ScaledObject配置 #

spec:
    minReplicaCount: 0
    maxReplicaCount: 5
    pollingInterval: 30
    cooldownPeriod: 30
    scaleTargetRef:
        name: demo-service
    triggers:
        -   type: postgresql
            metadata:
                connection: "postgresql://host.minikube.internal:5432"
                userName: "postgres"
                passwordFromEnv: demo-service-secret-keda-password
                host: "host.minikube.internal"
                dbName: "postgres"
                sslmode: disable
                port: "5432"
                query: "select value from keda where id = 1"
                targetQueryValue: "3"

PostgreSQL查询结果 #

postgres=# select value from keda where id = 1;
 value 
-------
     2
(1 row)

KEDA Pod错误日志 #

2022-11-07T14:48:59Z    ERROR   Reconciler error    {"controller": "scaledobject", "controllerGroup": "keda.sh", "controllerKind": "ScaledObject", "scaledObject": {"name":"postgres-scaledobject","namespace":"default"}, "namespace": "default", "name": "postgres-scaledobject", "reconcileID": "06cbd2e8-93ac-43a1-8cf0-ac4852eac4be", "error": "HorizontalPodAutoscaler.autoscaling \"keda-hpa-postgres-scaledobject\" is invalid: spec.metrics[0].external.target.averageValue: Invalid value: resource.Quantity{i:resource.int64Amount{value:0, scale:0}, d:resource.infDecAmount{Dec:(*inf.Dec)(nil)}, s:\"0\", Format:\"DecimalSI\"}: must be positive"}

解决步骤 #

1. 清理无效HPA资源
   由于之前设置负值导致KEDA生成的HPA存在无效配置，即使修改ScaledObject也无法自动修复，需手动删除旧HPA：

   kubectl delete hpa keda-hpa-postgres-scaledobject -n default
   

2. 触发ScaledObject重新 reconcile
   删除旧HPA后，让KEDA重新生成正确的HPA配置，可通过重新部署ScaledObject或添加注解触发：

   kubectl apply -f your-scaledobject-file.yaml
   # 或使用注解触发 reconcile
   kubectl annotate scaledobject postgres-scaledobject keda.sh/reconcile=true -n default --overwrite
   

3. 验证核心配置正确性

   • 确认targetQueryValue为正整数，无格式错误
   • 检查PostgreSQL查询语句select value from keda where id = 1始终返回单个非零数值，避免返回空结果
   • 验证密码环境变量demo-service-secret-keda-password已正确注入KEDA pod，可通过kubectl exec -it <keda-pod-name> -n keda env查看
   • 测试KEDA pod与PostgreSQL的连通性：在KEDA pod内执行psql postgresql://postgres:<password>@host.minikube.internal:5432/postgres确认连接正常

4. 检查KEDA版本（可选）
   若使用较旧版本的KEDA，可能存在配置缓存bug，建议升级到官方稳定版。

内容的提问来源于stack exchange，提问作者D. Joe