Docker runs unix processes with strong guarantees of isolation and repeatability across servers. Docker is a great building block for automating distributed systems: large-scale web deployments, database clusters, continuous deployment systems, private PaaS, service-oriented architectures, etc.

Docker Compose is a tool for running multi-container applications on Docker defined using the Compose file format. A Compose file is used to define how the one or more containers that make up your application are configured. Once you have a Compose file, you can create and start your application with a single command: docker compose up.
About update and backward compatibility

Docker Compose V2 is a major version bump release of Docker Compose. It has been completely rewritten from scratch in Golang (V1 was in Python). The installation instructions for Compose V2 differ from V1. V2 is not a standalone binary anymore, and installation scripts will have to be adjusted. Some commands are different.

For a smooth transition from legacy docker-compose 1.xx, please consider installing compose-switch to translate docker-compose ... commands into Compose V2's docker compose .... . Also check V2's --compatibility flag.

Helm is a tool for managing Kubernetes charts. Charts are packages of pre-configured Kubernetes resources.

Configuration files common to github.com/containers, a collection of golang libraries, configuration files, manpages, and debugging tools used by various tools, such as skopeo, cri-o and podman.

passt implements a translation layer between a Layer-2 network interface and
native Layer-4 sockets (TCP, UDP, ICMP/ICMPv6 echo) on a host. It doesn't
require any capabilities or privileges, and it can be used as a simple
replacement for Slirp.

skopeo is a command line utility for various operations on container images and
image repositories. skopeo is able to inspect a repository on a Docker registry
and fetch images layers. skopeo can copy container images between various
storage mechanisms.

umoci modifies Open Container images.

umoci (pronounced /uːmoˈʨi/ or approximately "oo-mo-tchee") is a reference implementation of the OCI image specification and provides users with the ability to create, manipulate, and otherwise interact with container images. It is designed to be as small and unopinonated as possible, so as to act as a foundation for larger systems to be built on top of.