What's the difference between Docker Compose and Kubernetes?

Question

Containers:

• Containers are at the core of the other technologies listed here

Docker:

• Docker is a popular implementation of the technology that allows applications to be bundled into a container.
• docker is a command-line tool to manage images, containers, volumes, and networks

Docker Compose

• Docker Compose is the declarative version of the docker cli
• It can start one or more containers
• It can create one or more networks and attach containers to them
• It can create one or more volumes and configure containers to mount them
• All of this is for use on a single host

Docker Classic Swarm

• Docker swarm has been abandoned by Docker Inc. and is not being actively maintained or supported.
• Docker Swarm is for running and connecting containers on multiple hosts.
• Docker Swarm is a container cluster management and orchestration tool.
• It manages containers running on multiple hosts and does things like scaling, starting a new container when one crashes, networking containers ...
• The Docker Swarm file named stack file is very similar to a Docker Compose file
• The only comparison between Kubernetes and Compose is at the most trivial and unimportant level: they both run containers, but this says nothing to help one understand what the two tools are and where they are useful. They are both useful for different things

Kubernetes

• Kubernetes (K8S) is a distributed container orchestration tool initially created by Google
• It was open-sourced in 2014 and handed over to the Cloud Native Computing Foundation (CNCF) the following year
• The CNCF is an industry body with hundreds of members drawn from the majority of large cloud, software and hardware companies
• At the time of writing (late 2021) there are nearly a thousand K8S related projects split into around twenty classes with a total of over $21 billion dollars in funding
• Kubernetes (2021) is the most popular distributed system orchestrator in the world with 88% adoption
• Because of its near ubiquity, K8S has become the most popular contemporary platform for innovative system development in 2021

In addition to @yamenk's answer, I'd like to add a few details here which might help people with their journey of understanding Kubernetes.

Short answer:

• docker-compose: is a tool that takes a YAML file which describes your multi-container application and helps you create, start/stop, remove all those containers without having to type multiple docker ... commands for each container.
• Kubernetes: is a platform for managing containerized workloads and services, that facilitates both declarative configuration and automation. What? 🤔 Keep reading...

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Docker Compose

(from the docs): Compose is a tool for defining and running multi-container Docker applications. With Compose, you use a YAML file to configure your application’s services. Then, with a single command, you create and start all the services from your configuration. Compose has commands for managing the whole lifecycle of your application:

• Start, stop, and rebuild services
• View the status of running services
• Stream the log output of running services
• Run a one-off command on a service

Kubernetes

(from Introduction to Kubernetes): Kubernetes is a container orchestrator like Docker Swarm, Mesos Marathon, Amazon ECS, Hashicorp Nomad. Container orchestrators are the tools which group hosts together to form a cluster, and help us make sure applications:

• are fault-tolerant,
• can scale, and do this on-demand
• use resources optimally
• can discover other applications automatically, and communicate with each other
• are accessible from the external world
• can update/rollback without any downtime.

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Many people argue that Kubernetes is hard to learn. It's because it solves a series of problems and people try to understand without knowing all the prerequisites. This makes it complicated. Start putting the pieces of the puzzle together by reading about concepts/terms like the following. This process will help you understand the kind of problems Kubernetes tries to solve:

• 12-factor apps,
• Automatic binpacking,
• Self-healing mechanisms,
• Horizontal scaling,
• Service discovery and Load balancing,
• Automated rollouts and rollbacks,
• Blue-Green deployments / Canary deployments
• Secrets and configuration management,
• Storage orchestration

And because there are a lot of different things around containers and their management, keep an eye on the Cloud Native landscape:

Interactive version here: landscape.cncf.io/

Updates

May 2020: Docker Compose Specification is now an open standard

Working with AWS, Microsoft, and others in the open source community, we have extended the Compose Specification to support cloud-native platforms like Kubernetes, and Amazon ECS in addition to the existing Compose platforms. More here: blog / compose-spec.io

If you are networking containers within the same host go for docker compose.

If you are networking containers across multiple hosts go for kubernetes.

first distinction is between the container engine and the container orchestrator.

docker is a container engine, it makes you build and run usually no more than one container at most, locally on your PC for development purposes.

docker-compose is a Docker utility to run multiple containers and let them share volumes and networking via the docker engine features, runs locally to emulate service composition and remotely on clusters.

Kubernetes is a container orchestration platform, it takes care of running containers and enhancing the engine features so that containers can be composed and scaled to serve complex applications (sort of PaaS, managed by you or cloud provider). Main Kubernetes feature is to decouple infrastructure from application using containers, and it's also open for other engines that Docker, for example it can run containers with rkt or cri-o.

Docker cloud is also a PaaS offer that will let you run and orchestrate containers through the docker engine API.

Now depending on your needs, level of control on infrastructure and target audience you can use either Kubernetes on baremetal, or Azure ACS or Google GKE, etc...

Hope this helped :) Regards

Docker Compose is not a production ready tool. It works great for PoC or development environments, but lacks a lot of the capabilities that are more or less table stakes for serious production use. Swarm is more production-ready, but I would never invest into Swarm in a greenfield scenario. Kubernetes has won the orchestration battle, as evidenced by its inclusion into Docker Desktop and it being offered by all major cloud providers. Kubernetes is much more capable and has far more community and corporate support.

I would recommend diving into some of the Kubernetes tutorials available at Pluralsight, Linux Academy, etc. and spinning up a cluster to play around with in your cloud platform of choice (EKS, AKS, GKE, etc.). If you are trying to spin up on bare metal, take a look at OpenShift, but recognize that you lose some of the magic of Kubernetes in this setup.