kitt-shell 0.5

A portable containerized shell

Kitt

Kitt is a container based portable shell environment.

Spawn your shell, with your tools, and your config, anywhere.

Installation

Install Docker and python3.

➜  curl -sSL https://get.docker.io | bash
➜  pip install kitt-shell

How to use Kitt

Fill a configuration file (see examples folder) either in toml or json format. Feed it to Kitt and let the magic happend !

➜  kitt build -f examples/devops.conf devops
✓ Build success !

➜  kitt run devops
user@kitt:~# 

Few commands workflow examples are available in examples folder.

Kitt CLI reference

➜  kitt --help

Usage: kitt.py [OPTIONS] COMMAND [ARGS]...

Options:
  -h, --help   Show this message and exit.
  -d, --debug  Debug mode

Commands:
  build    Build image from source config file
  list     List local images
  patch    Patch image runtime metadata
  prune    Prune local images
  pull     Pull image and exit
  push     Push image to registry
  refresh  Pull latest version of local images
  remove   Remove local image
  run      Run kitt shell
  version  Show version

Configuration

Basics

[options]
docker_in_docker = false    # Share docker socket
forward_x11 = false         # Configure x11 forward

[workspace]
tools = []              # Catalog tools
user = "user"           # Username inside container
hostname = "kitt"       # Container hostname
default_shell = "bash"  # One of bash, zsh, sh, dash

# [[workspace.envs]]  # Container exported ENV (multiple)
# name = ""
# value = ""

# [[workspace.volumes]]   # Container bind volumes (multiple)
# host = ""   # Local directory
# bind = ""   # Bind inside container
# mode = ""   # Mode (default is 'rw')

For more details about Catalog tool installer, see tools installation section.

Plugins

Kitt offers multiple optional plugins to improve environment customization.

Plugin	Description
bash	configure bash
zsh	install and setup Zsh (oh-my-zsh)
copy	copy local files inside container
download	download ressources inside container
git	clone git repository inside container
tmux	configure Tmux
screen	configure GNU Screen
sercrets	add secrets

See PLUGINS.md for configuration details.

See plugins.py to implement your own plugin.

How does it work ?

Kitt will build an OCI Container Image (compatible with Docker, Podman, ...), according to the provided configuration file. It will install requested tools inside, setup your desired shell(s), shortcuts, completion, plugins, and add your configuration files.

At runtime, Kitt will create a container from this image, spawn a shell inside and attach it to your current TTY.

Tools installation

For the tool installation part, Kitt relies on Catalog. It does provide an uniform way of installing tools inside containers, and can be extended if necessary.

Catalog is also available inside the container :

➜  kitt run devops
root@kitt:~# catalog htop pulumi

[+] Installing htop
...

Containerization

At first, kitt was meant to run with Podman as it is rootless by design (which solves uig/gid mapping problems).
However, for multiple reasons, it should now mainly run with Docker. Podman support is in progress, see branch feat/podman.

What is UID/GID reflexion ?

TL;DR: It's great for shared folders file rigths.

Kitt uses fixuid project to reflect host user UID/GID inside the container. What does that means ?

As Docker containers run as root (except rootless ones, but still), if you have a shared volume between your host and container, files created inside the container will be owned by root on the host. This mecanism makes working with volumes for user owned files very unconvenient.

With fixuid, the user inside the container will have the exact same real uid as your current host user. So if you bind a directory (your home for example), any file created by the user inside the container will be own by your user on the host side instead of root.