https://github.com/jmservera/min

Smallest possible Docker image
https://github.com/jmservera/min

Last synced: 8 days ago
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Smallest possible Docker image

• Host: GitHub
• URL: https://github.com/jmservera/min
• Owner: jmservera
• License: mit
• Created: 2021-11-12T00:19:22.000Z (about 3 years ago)
• Default Branch: main
• Last Pushed: 2022-02-08T11:04:24.000Z (almost 3 years ago)
• Last Synced: 2024-04-13T03:17:43.708Z (9 months ago)
• Language: Assembly
• Size: 981 KB
• Stars: 0
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# Minimal Docker image to explain Docker from the beginning

The smallest possible Docker image contains a Hello World application that avoids libc so has 0 dependencies and uses less than 9kB.

> Take a look at [linux syscall](https://github.com/raminfp/linux_syscall/blob/master/C_syscall_without_standard_library_linux/assm_syscall.c) for a Hello World without libc.

You can create the image with `docker build -t minimal .`

## More examples

The `Dockerfile.compiler` creates the same minimal image, but uses a multibuild stage to compile the C program using gcc. Build this one with `docker build -t minimal -f Dockerfile.compiler .`.	

To be able to see what's into the image, you need some more basic libraries and tools. These are provided with the `Dockerfile.sh` one, where we provide a bin folder with the `sh` executable, and the lib and lib64 folders with the libc libraries needed for sh.

Create the image with `docker build -t minsh -f Dockerfile.sh .`, and run it with `docker run -it minsh sh`.

## Navigating the Linux shell without any tool

With the last image, there's only the sh and hello executables. But you can still do some basic things with the shell:

* `cd` to change the current directory

* `echo *` to list the files in the current directory

* `pwd` to show the current directory

* You can create a cat command with this shell function:

    ```sh

    cat() {

    while read line;

        do echo $line

    done < $1

    }

    ```

* Now you can do `cat /proc/version` to see the kernel version or `cat /proc/sys/kernel/hostname` to see the hostname.