Docker containers can communicate with each other in several ways:
1. Links: You can use the `—link` flag to allow two containers to communicate with each other. For example, you can start a web server with a link to a database server.
\`\`\` docker run -d —name=web-server —link=db-server db-server-image \`\`\` Note: Links are a legacy option in Docker and may eventually be removed.1. Docker Networks: You can create a custom network in Docker and attach containers to it. Containers on the same network can communicate with each other directly.
\`\`\`bash docker network create my-network docker run -d —network=my-network —name=db-server db-server-image docker run -d —network=my-network —name=web-server web-server-image \`\`\`1. Exposed Ports: If a container has exposed ports, other containers can communicate with it through those ports.
\`\`\`bash docker run -d -p 8080:80 —name=web-server web-server-image \`\`\`1. Volumes: You can use volumes to share files between containers. This can be useful if you need to share configuration files or other data.
1. Docker Compose: Docker Compose is a tool that is used to define and manage multi-container Docker applications. With Docker Compose, you can set up networks, volumes, and environment variables that will be shared between containers.
Here is an example of `docker-compose.yaml` file:
```
version: ‘3‘
services:
web:
build: .
ports:
– “5000:5000“
networks:
– webnet
redis:
image: “redis:alpine“
networks:
– webnet
networks:
webnet:
```
In this setup, the `web` service can access the `redis` service at the hostname `redis` (for example, `redis:6379`).
Remember, by default, docker containers can make connections to the outside world, but the outside world cannot connect to containers. For that to happen, you need to map ports or link containers as described above.
