[Container-tools] CRI-O vs. ContainerD

[Daniel J Walsh]

On 03/20/2017 12:33 PM, Josh Berkus wrote:
> ... can someone give me a practical rundown?
>
> Speaking as a Kubernetes user, how are these different?
>
CRI-O is a CRI Daemon that is being developed to support Kubernetes
workloads using three sub packages

github.com://containers/storage
github.comf://containers/image
github.com://opencontainers/runtime-spec and
github.com://opencontainers/runc

Red Hat is taking the lead on this effort, but we have major
contributors from Suse, Intel, IBM.  It is part of an k8s incubator
project.  Available now in Rawhide as the ocid package.  We are
currently passing about 1/3 of the k8s CRI test suite.  Hope to pass all
within 6 months.

ContainerD is an new monolithic daemon from Docker Inc. It includes what
is containerd from the docker project which was a daemon built mainly to
support the Swarm workloads as well as sucked parts of the docker daemon
out to handle container storage and pulling/pushing images. As of now it
does not support k8s CRI, although that is clearly Docker Inc's aim.  It
also only supports storage on Overlay2 and Aufs.  They did some redesign
of the Storage layer to make it different then Docker mechanism.  (We
based containers/storage off of the Docker storage).  Containerd still
has Solomon Sykes as the BDL of containerd.  We submitted pull requests
to use containers/storage and containers/image to containerd but was
rejected by the containerd team.  Docker would like to see containerd be
the one Daemon to handle all container workloads.  We think at some
point in the future the upstream docker project will move to containerd.