build nos 2 ultimos nodes

Olá, Thyago. Tudo bem?

É possivel sim você utilizar o build do primeiro container nos outros. Você poderia deixar assim:

version: '3'
services:
    nginx:
        build:
            dockerfile: ./docker/nginx.dockerfile
            context: .
        image: douglasq/nginx
        container_name: nginx
        ports:
            - "80:80"
        networks: 
            - production-network
        depends_on: 
            - "node1"
            - "node2"
            - "node3"

    mongodb:
        image: mongo
        networks: 
            - production-network

    node1:
        build:
            dockerfile: ./docker/alura-books.dockerfile
            context: .
        image: douglasq/alura-books
        container_name: alura-books-1
        ports:
            - "3000"
        networks: 
            - production-network
        depends_on:
            - "mongodb"

    node2:
        image: douglasq/alura-books
        container_name: alura-books-2
        ports:
            - "3000"
        networks: 
            - production-network
        depends_on:
            - "mongodb"

    node3:
        image: douglasq/alura-books
        container_name: alura-books-3
        ports:
            - "3000"
        networks: 
            - production-network
        depends_on:
            - "mongodb"

networks: 
    production-network:
        driver: bridge

O build do node2 e node3 usarão a mesma imagem do node1.

Bons estudos!