I’m having trouble with data persistence in my Docker Compose setup for a Spring Boot application that uses PostgreSQL. The data persists only when I stop the PostgreSQL container individually and start it again, but when I bring the entire Docker Compose stack down and then up again, the data is lost.
Here’s my docker-compose.yml file:

version: '3.8'
services:
  postgres:
    image: postgres:latest
    container_name: postgres-container
    environment:
      POSTGRES_DB: jwt_security
      POSTGRES_USER: postgres
      POSTGRES_PASSWORD: password
    volumes:
      - postgres-data:/var/lib/postgresql/data
    ports:
      - "5431:5432"

  app:
    image: my-spring-app # Replace with your actual Spring Boot app image name
    container_name: spring-boot-app
    environment:
      SPRING_DATASOURCE_URL: jdbc:postgresql://postgres:5432/jwt_security
      SPRING_DATASOURCE_USERNAME: postgres
      SPRING_DATASOURCE_PASSWORD: password
    depends_on:
      - postgres
    ports:
      - "8080:8080" # Adjust if your Spring Boot app runs on a different port

volumes:
  postgres-data:
    external: true

Steps I Have Tried:

1. Remove Existing Containers and Volumes:

   docker-compose down -v
   docker volume rm postgres-data
   

2. Create the External Volume:

   docker volume create --name postgres-data
   

3. Bring Up the Containers:

   docker-compose up
   

Problem:

After setting up the environment and adding data to the database, I can see the data using:

docker exec -it postgres-container psql -U postgres -d jwt_security
SELECT * FROM _user;

However, when I run docker-compose down and then docker-compose up, the data is lost. Here are the details of what I observe:

1. The external volume seems to be created and used correctly.
2. When I inspect the volume, it appears to be mounted correctly.
3. Logs from the PostgreSQL container indicate the database system initializes correctly but does not retain data.