yaml: line 8:did not find expected key - dockerfile

Question

these are my first times with docker, I'm trying to put the directives for MariaDB in my composer file. Once the file is written, if I try to run the docker compose up command, it gives me the following error: yaml: line 8: did not find expected key. Does anyone have the same problem as me? How can I solve? Thanks so much.
Below is my docker-compose.yaml file
version: '3'
services:
backend:
build: ./
restart: always
volumes:
- ./application:/var/www/html
ports: [80:80]
mariadb:
image: 'bitnami/mariadb:latest'
ports:
- '3306:3306'
volumes:
- './mariadb_data:/bitnami/mariadb'
environment:
- ALLOW_EMPTY_PASSWORD=yes
- MARIADB_DATABASE=db_test
- MARIADB_USER=test_user
- MARIADB_PASSWORD=password
- MARIADB_ROOT_HOST='%'
volumes:
application:
driver: local
mariadb_data:
driver: local

Answer 1

It happens when we do our own yml file for docker, you need to indent two spaces for sub entries under image details:
version: '1'
services:
mariadb-ikg:
image: bitnami/mariadb:10.3
ports:
- 3306:3306
volumes:
- D:/docker/bitnami-mariadb/databases:/bitnami/mariadb
environment:
- MARIADB_ROOT_PASSWORD=123456
phpfpm-ikg:
image: wyveo/nginx-php-fpm:php80
ports:
- 80:80
volumes:
- D:/docker/wyveo-nginx-php-fpm/wordpress:/usr/share/nginx/html
depends_on:
- mariadb-ikg