100-Days-Of-DevOps-Challenge-KodeKloud

Deploy an App on Docker Containers

The Nautilus Application development team recently finished development of one of the apps that they want to deploy on a containerized platform. The Nautilus Application development and DevOps teams met to discuss some of the basic pre-requisites and requirements to complete the deployment. The team wants to test the deployment on one of the app servers before going live and set up a complete containerized stack using a docker compose fie. Below are the details of the task:

• On App Server 2 in Stratos Datacenter create a docker compose file /opt/itadmin/docker-compose.yml (should be named exactly).

• The compose should deploy two services (web and DB), and each service should deploy a container as per details below:

For web service:

• Container name must be php_web.
• Use image php with any apache tag. Check docker hub for more details.
• Map php_web container’s port 80 with host port 6400
• Map php_web container’s /var/www/html volume with host volume /var/www/html.

For DB service:

• Container name must be mysql_web.
• Use image mariadb with any tag (preferably latest). Check mariadb for more details.
• Map mysql_web container’s port 3306 with host port 3306
• Map mysql_web container’s /var/lib/mysql volume with host volume /var/lib/mysql.
• Set MYSQL_DATABASE=database_web and use any custom user ( except root ) with some complex password for DB connections.

After running docker-compose up you can access the app with curl command curl <server-ip or hostname>:6400/

For more details check mariadb.

Note: Once you click on FINISH button, all currently running/stopped containers will be destroyed and stack will be deployed again using your compose file.

Steps

In this daily challenge, we are going to dockerized a 2-tier application. We have to create a docker compose file bundled with frontend and database containers. let’s start…

1. Login into App Server 2

2. Create a docker compose file

    sudo touch /opt/itadmin/docker-compose.yml
   

3. Copy-paste the following contents inside /opt/itadmin/docker-compose.yml

    services:
        web:
            image: php:apache
            container_name: php_web
            ports:
                - 6400:80
            volumes:
                - /var/www/html:/var/www/html
           
        db:
            image: mariadb:latest
            container_name: mysql_web
            ports:
                - 3306:3306
            volumes:
                - /var/lib/mysql:/var/lib/mysql
            environment:
                - MARIADB_DATABASE=database_web
                - MARIADB_USER=kkloud
                - MARIADB_PASSWORD=your-user-password
                - MARIADB_ROOT_PASSWORD=your-root-password
   

4. Let’s Test

    docker compose -f /opt/itadmin/docker-compose.yml
   

It was actually a sample test, web server is not rely on db. Otherwise we had to set connection between two services.

Good to Know?

Multi-Container Applications

• Separation of Concerns: Each service has specific responsibility
• Scalability: Scale services independently
• Maintainability: Update services without affecting others
• Technology Diversity: Use different technologies per service

Two-Tier Architecture

• Presentation Tier: Web server (PHP/Apache)
• Data Tier: Database server (MariaDB/MySQL)
• Communication: Services communicate over network
• Stateless Web: Web tier should be stateless for scalability

Docker Compose Benefits

• Single Command: Start entire application stack
• Service Discovery: Services can communicate by name
• Environment Isolation: Consistent development environment
• Volume Management: Persistent data across container restarts

Database Configuration

• Environment Variables: Configure database credentials
• Initialization: Database creates schema on first run
• Persistence: Use volumes to persist database data
• Security: Use strong passwords and limit access

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