My simple Flask application runs perfectly in Docker container, but when I try to deploy it in Kubernetes using Helm, I keep encountering issues. The deployment shows READY 0/1 and AVAILABLE 0, indicating that no pods are running successfully.

My .yaml files:

Chart.yaml

apiVersion: v2
name: simpleflask
description: Helm chart for deploying a Flask application
version: 1.0.0
appVersion: "latest"

values.yaml

image:
  repository: simpleflask

service:
  port: 5000

hpa:
  enabled: true
  minReplicas: 1
  maxReplicas: 5
  metrics:
    resource:
      name: cpu
      target:
        type: Utilization
        averageUtilization: 80

deployment.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: simpleflask-web
spec:
  replicas: 1
  selector:
    matchLabels:
      app: simpleflask
  template:
    metadata:
      labels:
        app: simpleflask
    spec:
      containers:
      - name: simpleflask
        image: simpleflask
        port:
        - containerPort: 5000
      resources:
        requests:
          cpu: 100m
          memory: 128Mi
        limits:
          cpu: 500m
          memory: 512Mi

service.yaml

apiVersion: v1
kind: Service
metadata:
  name: simpleflask-app
spec:
  selector:
    app: simpleflask
  ports:
  - protocol: TCP
    port: 5000
    targetPort: 5000
  type: NodePort

Here’s my build and deployment process:
minikube start
eval $(minikube docker-env)
docker build -t simpleflask .
helm install simpleflask/ –generate-name

Output when i’m trying to deploy:

$ helm install simpleflask-chart/ --generate-name
W0510 07:57:58.783567   10112 warnings.go:70] unknown field "spec.template.spec.containers[0].port"
W0510 07:57:58.784104   10112 warnings.go:70] unknown field "spec.template.spec.resources"
NAME: simpleflask-chart-1715320678
LAST DEPLOYED: Fri May 10 07:57:58 2024
NAMESPACE: default
STATUS: deployed
REVISION: 1

$ kubectl get all
NAME                               READY   STATUS             RESTARTS   AGE
pod/simpleflask-app-55c4c7864f-m2fpp   0/1     ImagePullBackOff   0          53s

NAME                  TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)          AGE
service/kubernetes    ClusterIP   10.96.0.1       <none>        443/TCP          8m8s
service/simpleflask-app   NodePort    10.111.83.200   <none>        5000:30996/TCP   53s

NAME                          READY   UP-TO-DATE   AVAILABLE   AGE
deployment.apps/simpleflask-app   0/1     1            0           53s

NAME                                     DESIRED   CURRENT   READY   AGE
replicaset.apps/simpleflask-app-55c4c7864f   1         1         0       53s

I’ve experimented with different Helm chart configurations, but I keep getting the same error (or a similar one). And also i was pulling image from Docker Hub. Could you help me identify the root cause of this issue?

I expect my app to be running and accessible on port 5000.