Kubernetes探测器在Tomcat上失败

Question

我在Kubernetes集群的Docker映像中运行Tomcat上的Java webapp。服务运行良好，我正试图设置活跃度和准备度探测器。

我没有找到关于最佳实践wrt、Tomcat和Kubernetes的具体文档，但我认为文档后面的HTTP GET请求是合适的，如下所示：

    livenessProbe:
      failureThreshold: 3
      httpGet:
        path: /
        port: 8080
        scheme: HTTP
      initialDelaySeconds: 20
      periodSeconds: 20
      successThreshold: 1
      timeoutSeconds: 3

Events:
  Type     Reason                 Age               From               Message
  ----     ------                 ----              ----               -------
  Normal   Scheduled              3m                default-scheduler  Successfully assigned xxxxx-service-7f8f76988-lkxdf to kube-03
  Normal   SuccessfulMountVolume  3m                kubelet, kube-03   MountVolume.SetUp succeeded for volume "default-token-b6tps"
  Normal   Created                1m (x3 over 3m)   kubelet, kube-03   Created container
  Normal   Started                1m (x3 over 3m)   kubelet, kube-03   Started container
  Warning  Unhealthy              42s (x7 over 3m)  kubelet, kube-03   Liveness probe failed: Get http://10.233.96.19:8080/: net/http: request canceled (Client.Timeout exceeded while awaiting headers)
  Normal   Pulling                40s (x4 over 3m)  kubelet, kube-03   pulling image "xxxxx:4999/xxxxx/xxxxxservice:v1.3.0"
  Normal   Pulled                 40s (x4 over 3m)  kubelet, kube-03   Successfully pulled image "xxxxx:4999/xxxxx/xxxxxservice:v1.3.0"
  Normal   Killing                40s (x3 over 2m)  kubelet, kube-03   Killing container with id docker://xxxxx-service:Container failed liveness probe.. Container will be killed and recreated.

相关问题似乎是由于启动时间长于initialdelayseconds参数中设置的时间（例如this)，就像错误消息所指示的那样。然而，在这种情况下，Tomcat和webapp在几秒钟后确实可以访问，所以启动时间不是这里的问题。

以下是部署规范：

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: xxxxx-service
  namespace: xxxxx
spec:
  replicas: 1
  template:
    metadata:
      labels:
        app: xxxxx-service
    spec:
      imagePullSecrets:
      - name: regsecret
      containers:
      - image: xxxxxservice:v1.3.0
        imagePullPolicy: Always
        name: xxxxx-service
        ports:
        - containerPort: 8080
          protocol: TCP
        resources:
          limits:
            cpu: "0.2"
            memory: 4Gi

Answer 1

我也有同样的问题。经过一段时间的调查，我发现我的应用程序中的tomcat服务器需要大约35秒才能启动。因此，我将initialDelaySeconds更改为大于35秒。我还将超时秒增加到10秒，并将periods_second增加到10秒。Kubernetes探测器随后完美地工作了。