3 🏃‍♂️ Docker Run

🏃‍♂️ Mastering the docker run Command

📋 Basic Syntax

docker run [OPTIONS] IMAGE_NAME[:TAG] [COMMAND] [ARG...]

If the tag version is not specified, Docker defaults to latest.

⚙️ Common Options

Option	Description
--name	Assigns a custom name to the container
-e or --env	Sets environment variables inside the container
-d or --detach	Runs the container in detached mode (background)
-p or --publish	Maps container port to host port (host_port:container_port)

🛠️ Practical Examples

Executing Commands in a Container

docker run ubuntu sleep 5

• Starts the container →
• Runs sleep for 5 seconds →
• Stops the container

Verify the execution:

docker ps -a

📂 Accessing Files in a Running Container

docker exec [containerID] cat /etc/hosts

Prints the content of the hosts file.

🔗 Attach, Detach, and Reattach

docker run -d ubuntu

🖥️ Interactive Mode

docker run -it centos bash

• -i: Interactive input
• -t: Attach to the terminal
• Opens the Bash shell inside the container

🌐 Port Mapping

docker run -p 80:5000 kodekloud/webapp

• 80: Host port
• 5000: Container port

📂 Volume Mapping (Persistent Data)

docker run -v /opt/datadir:/var/lib/mysql mysql

Maps the external folder /opt/datadir to the MySQL container’s data directory.

🔎 Inspect Container Details

docker inspect [containerName]

📝 Viewing Container Logs

docker logs [containerName]

🌈 Setting Environment Variables

docker run -e APP_COLOR=blue simple-webapp

Verify the environment variable:

docker inspect [containerName]