Unable to start postgres docker container from docker-compose

Question

I am trying to start a postgresql docker container which is of version 10.5.

But before that I have used 9.6 version in the same docker-compose.yml file and there is no data populated in the database.

And now after changing the version of postgres container, I'm not able to run the docker-compose up. It is throwing the below error.

FATAL: database files are incompatible with server

DETAIL: The data directory was initialized by PostgreSQL version 9.6, which is not compatible with this version 10.5 (Debian 10.5-2.pgdg90+1)

This is how the docker-compose.yml file looks like.

version: '2'

services:

  postgres_service:
   container_name: postgresql_container
   restart: always
   image: postgres:10.5
   volumes:
     - postgres-data:/var/lib/postgresql/data
     - ./postgresql/init:/docker-entrypoint-initdb.d
   ports:
     - "5432:5432"
   environment:
     - POSTGRES_USER=admin
     - POSTGRES_PASSWORD=password
volumes:
  postgres-data:
    driver: local

Can someone please let me know where the issue is. Where am I making mistake? Do I need to delete any volumes before proceeding with the new postgres version?

I also have postgresql installed in my local.

postgres=# select version();
                                                               version                                                               
-------------------------------------------------------------------------------------------------------------------------------------
 PostgreSQL 10.10 (Ubuntu 10.10-1.pgdg18.04+1) on x86_64-pc-linux-gnu, compiled by gcc (Ubuntu 7.4.0-1ubuntu1~18.04.1) 7.4.0, 64-bit
(1 row)

Will this cause any issue?

Answer 1

The problem caused because the volume which your compose created to store your database still keep old data which initiated by PostgreSQL 9.6. That volume name is postgres-data which created when you use named volume on your docker-compose.yml. So simply to get rid of this, you can use some ways below:

1. Using docker-compose command:

Run docker-compose down -v, this will stop all your container inside that compose and remove all named volume inside that compose.

You could take a look at docker-compose down command

2. Using docker volume command:

Run docker volume ls to get list of current volumes on your machine, I think you will see your volume on that list too:

DRIVER              VOLUME NAME
local               postgres-data

Run docker volume rm postgres-data to remove that volume, if your container still running and you couldn't remove it then you can use -f to force remove it

Hope that helps!