Docker deployment in Laravel - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is Docker in the context of Laravel deployment?

Docker is a tool that packages your Laravel app and its environment into a container. This container runs the app the same way on any computer, making deployment easier and consistent.

beginner

Why use Docker Compose with Laravel?

Docker Compose lets you define and run multiple containers together, like your Laravel app, database, and cache. It helps manage all parts of your app in one place.

beginner

What is the purpose of a Dockerfile in Laravel deployment?

A Dockerfile is a recipe that tells Docker how to build the container for your Laravel app. It includes steps like installing PHP, copying your code, and setting up dependencies.

intermediate

How does Docker help with environment consistency in Laravel projects?

Docker containers include all software and settings needed to run Laravel. This means your app works the same on your computer, a teammate's, or a server, avoiding "it works on my machine" problems.

intermediate

What is a common way to handle Laravel's storage and cache folders in Docker?

Use Docker volumes to keep Laravel's storage and cache folders outside the container. This keeps data safe even if the container is rebuilt or removed.

What file defines how to build a Docker container for a Laravel app?

A docker-compose.yml

B Dockerfile

C artisan

D .env

The Dockerfile contains instructions to build the container image for your Laravel app.

Which tool helps run multiple containers like Laravel app and database together?

A Docker Compose

B Git

C NPM

D PHPUnit

Docker Compose manages multiple containers as a single service, useful for Laravel with database and cache.

Why use Docker volumes with Laravel containers?

A To keep data persistent outside containers

B To speed up container builds

C To increase container size

D To run containers faster

Volumes store data outside containers so it is not lost when containers stop or rebuild.

What command runs the containers defined in docker-compose.yml?

A docker build

B docker run

C php artisan serve

D docker-compose up

The command 'docker-compose up' starts all services defined in the docker-compose.yml file.

Which of these is NOT a benefit of Docker for Laravel deployment?

A Simplifies environment setup

B Ensures app runs the same everywhere

C Automatically writes Laravel code

D Helps manage dependencies

Docker does not write code; it helps package and run your app consistently.

Explain how Docker and Docker Compose work together to deploy a Laravel application.

Think about how you run your app and its database at the same time.

Describe the role of a Dockerfile in preparing a Laravel app for deployment.

It's like a recipe for making the app's home.

Practice

1. What is the main purpose of using Docker for deploying a Laravel application?

easy

A. To package the Laravel app with all its dependencies for consistent environments

B. To write Laravel code faster using special Docker commands

C. To replace Laravel's routing system with Docker's networking

D. To automatically generate Laravel migrations

Solution

1. Step 1: Understand Docker's role in deployment

   Docker packages the app and its environment so it runs the same everywhere.

2. Step 2: Relate this to Laravel deployment

   Laravel apps need PHP, web server, database, and dependencies; Docker bundles these.

3. Final Answer:

   To package the Laravel app with all its dependencies for consistent environments -> Option A

4. Quick Check:

   Docker ensures consistent app environment = C [OK]

Hint: Docker bundles app and tools for same setup everywhere [OK]

Common Mistakes:

• Thinking Docker speeds up coding
• Confusing Docker with Laravel features
• Believing Docker replaces Laravel's internal functions

2. Which file is typically used to define the environment and instructions to build a Docker image for a Laravel app?

easy

A. .env

B. docker-compose.yml

C. Dockerfile

D. composer.json

Solution

1. Step 1: Identify Dockerfile's purpose

   Dockerfile contains commands to build the Docker image step-by-step.

2. Step 2: Differentiate from other files

   docker-compose.yml runs containers; .env holds app configs; composer.json manages PHP packages.

3. Final Answer:

   Dockerfile -> Option C

4. Quick Check:

   Dockerfile builds image = A [OK]

Hint: Dockerfile builds image; compose runs containers [OK]

Common Mistakes:

• Confusing docker-compose.yml with Dockerfile
• Thinking .env defines Docker build steps
• Mixing composer.json with Docker configs

3. Given this docker-compose.yml snippet for Laravel:

services:
  app:
    build: .
    ports:
      - "8000:80"
    volumes:
      - .:/var/www/html
  db:
    image: mysql:8
    environment:
      MYSQL_ROOT_PASSWORD: secret

What happens when you run docker-compose up?

medium

A. It builds the app image, runs app on port 8000, and starts MySQL with root password

B. It only runs MySQL container without the app

C. It builds app image but fails to start MySQL due to missing password

D. It runs app on port 80 without MySQL

Solution

1. Step 1: Analyze docker-compose services

   App service builds from current folder, maps port 8000 to container's 80, mounts code volume. DB uses MySQL image with root password set.

2. Step 2: Understand docker-compose up behavior

   It builds and starts all defined services, so both app and db run with given configs.

3. Final Answer:

   It builds the app image, runs app on port 8000, and starts MySQL with root password -> Option A

4. Quick Check:

   Compose runs all services with configs = B [OK]

Hint: docker-compose up runs all services with given configs [OK]

Common Mistakes:

• Assuming only one service runs
• Missing environment variable for MySQL password
• Confusing port mapping direction

4. You wrote this Dockerfile for Laravel but get an error when building:

FROM php:8.1-fpm
RUN apt-get update && apt-get install -y git zip unzip
COPY . /var/www/html
RUN composer install

What is the likely cause of the build failure?

medium

A. apt-get update should be run after composer install

B. COPY command syntax is incorrect

C. PHP version 8.1-fpm is not supported by Laravel

D. Missing installation of Composer before running composer install

Solution

1. Step 1: Check Dockerfile commands order

   Composer is a separate tool and must be installed before running composer install.

2. Step 2: Identify missing Composer installation

   Dockerfile does not install Composer, so the command fails.

3. Final Answer:

   Missing installation of Composer before running composer install -> Option D

4. Quick Check:

   Composer must be installed before use = D [OK]

Hint: Install Composer before running composer commands [OK]

Common Mistakes:

• Assuming PHP image includes Composer by default
• Thinking COPY syntax causes build error
• Believing PHP 8.1-fpm is incompatible with Laravel

5. You want to deploy a Laravel app with Docker using docker-compose. You need PHP, MySQL, and Redis services. Which docker-compose.yml snippet correctly sets up these services with proper ports and environment variables?

hard

A. services:
app:
image: laravel/php
ports:
- "80:80"
db:
image: mysql
environment:
MYSQL_PASSWORD: secret
cache:
image: redis
ports:
- "6379:6379"

B. services:
app:
build: .
ports:
- "8080:80"
volumes:
- .:/var/www/html
db:
image: mysql:8
environment:
MYSQL_ROOT_PASSWORD: secret
cache:
image: redis:latest
ports:
- "6379:6379"

C. services:
app:
build: .
ports:
- "80:8080"
db:
image: mysql:5.7
environment:
MYSQL_ROOT_PASSWORD: root
cache:
image: redis
ports:
- "6379:6379"

D. services:
app:
build: .
ports:
- "8000:8000"
db:
image: mysql:8
environment:
MYSQL_ROOT_PASSWORD: secret
cache:
image: redis:latest

Solution

1. Step 1: Check app service configuration

   services: app: build: . ports: - "8080:80" volumes: - .:/var/www/html db: image: mysql:8 environment: MYSQL_ROOT_PASSWORD: secret cache: image: redis:latest ports: - "6379:6379" builds app from current folder, maps port 8080 to container port 80, and mounts code volume correctly.

2. Step 2: Verify db and cache services

   MySQL uses image mysql:8 with root password set; Redis uses latest image and exposes default port 6379.

3. Step 3: Compare other options for correctness

   services: app: image: laravel/php ports: - "80:80" db: image: mysql environment: MYSQL_PASSWORD: secret cache: image: redis ports: - "6379:6379". This option misses the volume mount for app code and uses wrong environment variable for MySQL (MYSQL_PASSWORD instead of MYSQL_ROOT_PASSWORD); the option with app ports "80:8080" has wrong port mapping; the option without ports for Redis misses exposing the Redis port.

4. Final Answer:

   services: app: build: . ports: - "8080:80" volumes: - .:/var/www/html db: image: mysql:8 environment: MYSQL_ROOT_PASSWORD: secret cache: image: redis:latest ports: - "6379:6379" -> Option B

5. Quick Check:

   Correct service setup with ports and env = A [OK]

Hint: Check ports and env vars carefully for all services [OK]

Common Mistakes:

• Swapping port mappings (host:container)
• Using wrong environment variable names
• Omitting volume mounts for app code
• Not exposing Redis port