Day 19 - Exploring Docker Volume & Network 🚀

Greetings DevOps enthusiasts! 🌟 Today, let's unravel the magic of Docker Volume and Network to enhance our container orchestration skills. 🐳✨

Docker Volume: Storage Sorcery! 📦

What is Docker Volume - Javatpoint

Docker volumes act as secret chambers outside containers, preserving precious data like databases even when containers bid adieu. It's like having a vault that multiple containers can access, ensuring data immortality. 💽

Docker Networking. When you install docker it creates… | by Sumeet Gyanchandani | Towards Data Science

Enter Docker networks – virtual hangout spots where containers mingle and chitchat. They form a communication bridge between containers and the host machine. 🤝 When containers talk, magic happens! Reference

install docker-compose:

Linux:

Run the following commands:

 sudo curl -L "https://github.com/docker/compose/releases/latest/download/docker-compose-$(uname -s)-$(uname -m)" -o /usr/local/bin/docker-compose

This command downloads the latest version of Docker Compose.

Apply executable permissions to the binary:

 sudo chmod +x /usr/local/bin/docker-compose

Verify the installation:
```
 docker-compose --version
```

Task-1: Multi-Container Symphony! 🎭

Creating a multi-container setup using Docker Compose is a breeze! Here's a step-by-step guide:

Create a docker-compose.yml File:

 version: "3.9" # specify the version of the compose file format
 services: # define the services or containers that make up your application
   web: # name of the first service
     image: nginx # name of the image to use for this service
     ports: # list of ports to expose on the host machine
       - "80:80"
     volumes: # list of volumes to mount on this service
       - ./web:/usr/share/nginx/html # mount the ./web directory on the host as /usr/share/nginx/html in the container
     depends_on: # list of services that this service depends on
       - api # depend on the api service
   api: # name of the second service
     build: ./api # path to the directory containing the Dockerfile for this service
     environment: # list of environment variables to pass to this service
       - MONGO_URL=mongodb://db:27017/test # specify the URL for connecting to MongoDB
     ports: # list of ports to expose on the host machine
       - "3000:3000"
     depends_on: # list of services that this service depends on
       - db # depend on the db service
   db: # name of the third service
     image: mongo # name of the image to use for this service
     volumes: # list of volumes to mount on this service
       - db_data:/data/db # mount a named volume called db_data as /data/db in the container
 volumes: # define any named volumes used by the services
   db_data: # name of the volume for persisting database data

Replace your-application-image and your-database-image with the actual images you want to use.

Run Containers in Detached Mode:
```
 docker-compose up -d
```
This starts your multi-container application in the background.
Scale the Services (Optional):
```
 docker-compose scale app=3
```
Adjust the number according to your needs. This showcases the power of scaling with Docker Compose!
View Container Status:
```
 docker-compose ps
```
Check the status of all containers. Ensure everything is up and running.
View Service Logs:
```
 docker-compose logs web
```
Review logs specific to the 'web' service. Useful for debugging or monitoring.
Bring Down Containers:
```
 docker-compose down
```
Stops and removes all containers, networks, and volumes associated with the application.

Task-2: Volume Ventures! 📂

Let's dive into the world of volumes:

Create Docker Volumes:
```
 docker volume create my_shared_volume
```
This creates a named volume named my_shared_volume.

Run Containers with Shared Volume:

 docker run -d --name container1 --mount source=my_shared_volume,target=/app your-image
 docker run -d --name container2 --mount source=my_shared_volume,target=/app your-image

Ensure to replace your-image with the actual image.

Verify Data Consistency:

 docker exec container1 cat /app/data.txt
 docker exec container2 cat /app/data.txt

Check if the data is consistent across both containers.

List Volumes:
```
 docker volume ls
```
Confirm the existence of the named volume.
Remove Volume (After You're Done):
```
 docker volume rm my_shared_volume
```

Let's dive in, learn, and share the joy! 🌍✨