Kubernetes runtimes
Kubernetes originally only supported Docker as a container runtime engine. But that is no longer the case. Kubernetes now supports several different runtimes:
- Docker (via a CRI shim)
- rkt (direct integration to be replaced with Rktlet)
- CRI-O
- Frakti (Kubernetes on the Hypervisor, previously Hypernetes)
- rktlet (CRI implementation for rkt)
- CRI-containerd
The major design policy is that Kubernetes itself should be completely decoupled from specific runtimes. The Container Runtime Interface (CRI) enables it.
In this section, you'll get a closer look at the CRI and get to know the individual runtime engines. At the end of this section, you'll be able to make a well-informed decision about which runtime engine is appropriate for your use case and under what circumstances you may switch or even combine multiple runtimes in the same system.
