1. Run a software into Docker Container

1. Pull the ubuntu image

   docker pull ubuntu:24.04 
   docker run --name my_ubuntu -it ubuntu:24.04 bash
   

   2. run a container from the ubuntu image

   docker exec -it my_ubuntu bash
   

   3. install golang inside the container

   apt update
   apt install golang
   go version           # verify install
   

   4. copy file from host machine to docker container

   1. make a directory in container

   2. copy file from host to container
      

   3. Verify the copied file

2. run the file

   

server.go

package main

import (
    "fmt"
    "net/http"
)

func main() {
    http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
        fmt.Fprintln(w, "Hello World!")
    })

    fmt.Println("Server is running on :8080")
    http.ListenAndServe(":8080", nil)
}

so Finally we run a software (server.go) into Docker Container.

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2. Create a Docker Image from a Running or Stopped Container

When to Use docker commit

• To quickly save changes made inside a container
• For experiments, debugging, or learning purposes

Step to create

1. Commit a Container to an Image

General Syntax : docker commit <container_id_or_name> <image_name>

Example

docker ps
docker commit ed06a473b329 go_server

This command creates a new image named go_server from the current state of the container ed06a473b329 (named my_ubuntu).

2. Verify the Created Image

docker images

3. Important Observation

The go_server image is exactly the snapshot of the my_ubuntu container at the time of commit.

• All installed packages
• All file changes
• All configurations

Everything is baked into the go_server image.

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Limitation of docker commit

Suppose:

• Your application file (e.g., server.go) changes

Then you must:

1. Run a container again
2. Manually edit files
3. Reinstall dependencies (Go, libraries)
4. Commit the container again

This process is manual, error-prone, and not reproducible.

Recommended Solution: Dockerfile

Instead of using docker commit, use a Dockerfile

Why Dockerfile is Better

docker commit	Dockerfile
Manual process	Automated
Not reproducible	Fully reproducible
Hard to maintain	Easy to maintain
Not version-controlled	Version-controlled

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Using Dockerfile : Run a software into Docker Container

1. Create the Dockerfile

   Dockerfile

   FROM ubuntu:24.04 
   RUN apt update
   RUN apt install -y golang
   WORKDIR /here
   COPY ./server.go  ./server.go
   

   Dockerfile Instruction	Explanation
   FROM ubuntu:24.04	Sets Ubuntu 24.04 as the base image that provides the Linux environment for the container.
   RUN apt update	Updates the system package index so new software can be installed correctly.
   RUN apt install -y golang	Installs the Go inside the container. The -y flag avoids manual confirmation.
   WORKDIR /here	Creates (if not exists) and switches to /here as the default working directory.
   COPY ./server.go ./server.go	Copies server.go from the host machine into the container’s working directory.

2. Build the Dockerfile and set name

3. Verfiy the image

4. Run the newly build image

5. Verify the output

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