Dockerized Spring Boot App Ignoring K8s/Kubernetes Environment Variables - spring-boot

Question

I have a very simple containerized Spring Boot application that I am trying to deploy to Docker Desktop Kubernetes.
My application.yaml looks like:
spring:
application:
name: helloworld
datasource:
password: ${SPRING_DATASOURCE_PASSWORD:secretpassword}
url: ${SPRING_DATASOURCE_URL:jdbc:postgresql://localhost:5432/helloworld}
username: ${SPRING_DATASOURCE_USERNAME:helloworld}
My Dockerfile looks like:
FROM openjdk:17 AS build
WORKDIR /workspace/app
COPY ../mvnw .
COPY ../.mvn .mvn
COPY ../pom.xml .
COPY ../src src
RUN ./mvnw install -DskipTests
FROM openjdk:17
VOLUME /tmp
COPY --from=build /workspace/app/target/*.jar app.jar
ENTRYPOINT ["java", "-jar","/app.jar"]
My deployment.yml looks like:
apiVersion: apps/v1
kind: Deployment
metadata:
creationTimestamp: null
labels:
app: helloworld
name: helloworld
spec:
replicas: 1
selector:
matchLabels:
app: helloworld
strategy: {}
template:
metadata:
creationTimestamp: null
labels:
app: helloworld
spec:
containers:
- image: xxx/yyy
name: zzz
resources: {}
env:
- name: SPRING_DATASOURCE_URL
value: "jdbc:postgresql:host.docker.internal:5432/helloworld"
status: {}
When I run kubectl get all I can see the pod is in a "CrashLoopBackoff"
When I run (before the pod crashes)
kubectl exec POD_NAME -- printenv
I can see the environment variable has been created (or I get an error I assume is because of the pod crashing: error: unable to upgrade connection: container not found ("yyy"))
But when I check the logs, I see:
SQL State : 08001
Error Code : 0
Message : Connection to localhost:5432 refused.
So the Spring Boot app is not picking up the environment variable SPRING_DATASOURCE_URL. It is still trying to connect to localhost:5432
If I add the env variable to the docker-compose (or IntelliJ runtime config) and run outside of K8s, the Spring Boot application picks up the environment variable.
Any idea what I am doing wrong?

Answer 1

The value of the env variable was causing the issue. It should be:
env:
- name: SPRING_DATASOURCE_URL
value: jdbc:postgresql://host.docker.internal:5432/helloworld
Because I was missing the // it kept referring trying to connect to localhost. Which was very confusing.