Postgres Docker Cluster with Connected Pgadmin

docker-compose.yml

version: '2'

services:
  cluster_master:
    image: 'bitnami/postgresql:latest'
    networks:
      - cluster_network
    ports:
      - '5432'
    volumes:
      - 'cluster_master_volume:/bitnami/postgresql'
    environment:
      - POSTGRESQL_POSTGRES_PASSWORD=postgres
      - POSTGRESQL_REPLICATION_MODE=master
      - POSTGRESQL_USERNAME=my_user
      - POSTGRESQL_PASSWORD=my_password
      - POSTGRESQL_DATABASE=my_database
      - POSTGRESQL_REPLICATION_USER=my_repl_user
      - POSTGRESQL_REPLICATION_PASSWORD=my_repl_password

      
  cluster_slave:
    image: 'bitnami/postgresql:latest'
    networks:
      - cluster_network
    ports:
      - '5432'
    depends_on:
      - cluster_master
    environment:
      - POSTGRESQL_POSTGRES_PASSWORD=postgres
      - POSTGRESQL_REPLICATION_MODE=slave
      - POSTGRESQL_USERNAME=my_user
      - POSTGRESQL_PASSWORD=my_password
      - POSTGRESQL_REPLICATION_USER=repl_user
      - POSTGRESQL_REPLICATION_PASSWORD=repl_password
      - POSTGRESQL_MASTER_HOST=cluster_master
      - POSTGRESQL_MASTER_PORT_NUMBER=5432
      - POSTGRESQL_REPLICATION_USER=my_repl_user
      - POSTGRESQL_REPLICATION_PASSWORD=my_repl_password

  cluster_pgadmin:
    image: 'dpage/pgadmin4'
    networks:
      - cluster_network
    ports:
      - '80'
    volumes:
      - 'cluster_pgadmin_volume:/var/lib/pgadmin'
    depends_on:
      - cluster_master
    environment:
      - PGADMIN_DEFAULT_EMAIL=admin@admin.com
      - PGADMIN_DEFAULT_PASSWORD=admin

volumes:
  cluster_master_volume:
  cluster_pgadmin_volume:
 
networks:
  cluster_network:
    driver: bridge
    ipam:
      driver: default
      config:
        - subnet: 172.55.0.0/24
          gateway: 172.55.0.1

# COMMAND TO EXECUTE:
#   docker-compose -p "pgc" up --detach --scale cluster_master=1 --scale cluster_slave=3
# EXPLANATION:
# 1. This command for docker compose will start postgres in master slave cluster with 1 master and 3 slaves
# 2. This will start the conneted PGAdmin tool as well under same network.
# 3. Once the Docker Compose is done, you will have 5 containers:
#     3.1 pgc_cluster_master_1
#     3.2 pgc_cluster_slave_1
#     3.3 pgc_cluster_slave_2
#     3.4 pgc_cluster_slave_3
#     3.5 pgc_cluster_pgadmin_1
# 4. Check the mapped port of 3.5 and open in browser
# 5. Add the new server and under:
#     5.1 GENERAL TAB:
#       5.1.1 Name = Anything You want to keep, eg: pgc_master
#     5.2 CONNECTION TAB:
#       5.2.1 host = pgc_cluster_master_1
#       5.2.2 Maintenance Database = postgres
#       5.2.3 port = 5432
#       5.2.4 username = postgres
#       5.2.5 password = postgres
#     ** REPEAT 5 for adding slave connections too
# 6. Now when you change anything under MASTER connection , it will reflect in the slave connections too, 
#     NOTE : Please refresh the object, to update the changes.