apiVersion: apps/v1
kind: Deployment
metadata:
  name: backend
  labels:
    app.kubernetes.io/name: backend
    app.kubernetes.io/component: api
spec:
  replicas: 2
  selector:
    matchLabels:
      app.kubernetes.io/name: backend
      app.kubernetes.io/component: api
  template:
    metadata:
      labels:
        app.kubernetes.io/name: backend
        app.kubernetes.io/component: api
    spec:
      terminationGracePeriodSeconds: 15
      initContainers:
        - name: wait-for-mysql
          image: busybox:1.36
          command:
            - sh
            - -c
            - |
              echo "Waiting for MySQL TCP to be available..."
              until nc -z mysql 3306; do
                echo "MySQL not reachable yet, retrying in 3s..."
                sleep 3
              done
              echo "MySQL TCP is up. Waiting 15s for full initialization..."
              sleep 15
              echo "Proceeding to start backend."
      containers:
        - name: backend
          image: scrum-backend:latest
          imagePullPolicy: IfNotPresent
          ports:
            - containerPort: 3001
              name: http
          env:
            - name: DB_HOST
              value: mysql
            - name: DB_PORT
              value: "3306"
            - name: DB_USER
              valueFrom:
                secretKeyRef:
                  name: mysql-secret
                  key: DB_USER
            - name: DB_PASSWORD
              valueFrom:
                secretKeyRef:
                  name: mysql-secret
                  key: DB_PASSWORD
            - name: DB_NAME
              valueFrom:
                secretKeyRef:
                  name: mysql-secret
                  key: DB_NAME
            - name: PORT
              value: "3001"
          resources:
            requests:
              cpu: 100m
              memory: 128Mi   # Request drives scheduling — keep low so pods fit on nodes
            limits:
              cpu: 500m
              memory: 512Mi   # Limit prevents OOMKill during startup spikes
          livenessProbe:
            httpGet:
              path: /api/health
              port: http
            initialDelaySeconds: 15
            periodSeconds: 10
            timeoutSeconds: 3
            failureThreshold: 3
          readinessProbe:
            httpGet:
              path: /api/health
              port: http
            initialDelaySeconds: 5
            periodSeconds: 5
            timeoutSeconds: 3
            failureThreshold: 5