Docker Compose and Kubernetes are both ways to run multi-container applications, but they sit at opposite ends of the operational complexity curve. Compose orchestrates containers on a single host using a single YAML file; Kubernetes (often abbreviated "k8s") orchestrates containers across a cluster of hosts with declarative reconciliation, automatic rescheduling on node failure, rolling updates, horizontal autoscaling, and an extensive RBAC model. A small team of one to ten people running ten or fewer self-hosted apps almost always wants Compose; an organization that needs zero-downtime upgrades or hundreds of microservices wants Kubernetes.

In a self-hosting context

For self-hosting an OSS replacement to a single SaaS — say a Mattermost instance for your team, or a Nextcloud share for your family — Compose on a $10/mo VPS is the right answer. Kubernetes only starts paying for itself once you need multi-node high availability or are running a platform on top of it. PaaS-style wrappers like CapRover, Dokku, and Coolify let you keep the Compose mental model while still getting one-click deploys and auto-TLS without writing Kubernetes manifests by hand.