Start sprinboot in minkube with custom context url as environnement variable

Question

I have a springboot app which I want to deploy on Kubernetes (I'm using minikube) with a custom context path taken from the environment variables.

I've compiled an app.war file. exported an environment variable in Linux as follow:

export SERVER_SERVLET_CONTEXT_PATH=/app

And then started my app on my machine as follow:

java -jar app.war --server.servlet.context-path=$(printenv CONTEXT_PATH)

and it works as expected, I can access my app throw browser using the url localhost:8080/app/

I want to achieve the same thing on minikube so I prepared those config files:

---

• Dockerfile:

  FROM openjdk:8
  ADD app.war app.war
  EXPOSE 8080
  ENTRYPOINT ["java", "-jar", "app.war", "--server.servlet.context-path=$(printenv CONTEXT_PATH)"]
  

---

• deployment config file:

  apiVersion: apps/v1
  kind: Deployment
  metadata:
    name: esse-deployment-1
    labels:
      app: esse-1
  spec:
    replicas: 1
    selector:
      matchLabels:
        app: esse-1
    template:
      metadata:
        labels:
          app: esse-1
      spec:
        containers:
        - image: mysql:5.7
          name: esse-datasource
          ports:
          - containerPort: 3306
          env: 
          - name: MYSQL_ROOT_PASSWORD
            value: root 
        - image: esse-application
          name: esse-app
          imagePullPolicy: Never
          ports:
          - containerPort: 8080
          env:
          - name: server.servlet.context-path
            value: /esse-1
        volumes:
          - name: esse-1-mysql-persistent-storage
            persistentVolumeClaim:
              claimName: mysql-persistent-storage-claim
  
  ---
  
  apiVersion: v1
  kind: Service
  metadata:
    name: esse-service-1
    labels:
      app: esse-1
  spec:
    selector:
      app: esse-1
    ports:
      - protocol: TCP
        port: 8080
        targetPort: 8080
    type: NodePort
  

However, the java container inside the pod fails to start and here's the exception is thrown by spring:

Initialization of bean failed; nested exception is java.lang.IllegalArgumentException: ContextPath must start with '/' and not end with '/'

Answer 1

Finally, I found a solution.

I configured my application to startup with a value for the context path taken from the environment variables by adding this line inside my application.properties:

server.servlet.context-path=${ESSE_APPLICATION_CONTEXT}

And the rest remains as it was, means I'm giving the value of the variable ESSE_APPLICATION_CONTEXT throw the config

env:
- name: ESSE_APPLICATION_CONTEXT
  value: /esse-1

And then starting the application without the --server.servlet.context-path parameeter, which means like that:

java -jar app.war

NOTE: as pointed by @mchawre's answer, it's also possible to make use of ConfigMap as documented in Kubernetes docs.