docker vs containerd

History of docker and k8s:

k8s was mainly supporting docker as container runtime
however other containerization vendors like rocket needed k8s support too!
so, k8s built this interface called CRI (container runtime interface) which helped k8s run other container runtime as long as they followed the OCI (open container initiative)
- OCI (imagespec + runtimespec)
- although this helped other container runtimes to use k8s but the fun fact was docker was not compatible with CRI!
- so k8s introduced something called dockershim to continue support for docker! (it was sort of a hack to bypass docker from using CRI)
Docker too contains several tools put together ex-
- cli, api, build, volumes, auth, security and containerd
- containerd is CRI compatible and thus docker could be run by containerd instead of dockershim now and its support by k8s was remved in v1.24!
now containerd contains cli-nerdctl and cli-ctr to manage runtimes
while k8s has its own tool called cli-crictrl

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