STATUS: EXPERIMENT - Let me know what you think
k3c
is a local container engine designed to fill the same gap Docker does
in the Kubernetes ecosystem. Specifically k3c
focuses on developing and
running local containers, basically docker run/build
. Currently k3s
, the
lightweight Kubernetes distribution,
provides a great solution for Kubernetes from dev to production. While
k3s
satisifies the Kubernetes runtime needs, one still needs to run
docker
(or a docker-like tool) to actually develop and build the container
images. k3c
is intended to replace docker
for just the functionality
needed for the Kubernetes ecosystem.
There really is nothing better than the classic Docker UX of run/build/push/pull
.
This tool copies the same UX as classic Docker (think Docker v1.12). The intention
is to follow the same style but not be a 100% drop in replacement. Behaviour and
arguments have been changed to better match the behavior of the Kubernetes ecosystem.
One change, for example, is that start/restart will always give you a fresh container
because pods in Kubernetes are always ephemeral.
k3c
, similar to k3s
and old school docker, is packaged as a single binary, because nothing
is easier for distribution than a static binary.
Fundamentally k3c
is a built on the Container Runtime Interface (CRI). In fact it's really like a nicer version of
of cri-tool. CRI doesn't cover image building
and some other small image tasks like tag and push. For image building Moby's buildkit
is used internally, and for other things OCI's containerd is used.
k3c
runs as a daemon either as root or one per user for rootless support. NOTE: rootless isn't currently
working, that's just the design right now. The daemon exposes a GRPC API. For building the buildkit API is just
exposed directly from the k3c socket. containerd
, buildkitd
, and containerd-cri
are all embedded
directly into the k3c binary.
Builds are currently run via k3c
if it is available on the $PATH otherwise docker
is assumed to be available.
To build the k3c
binary:
make build
To build the k3c
image:
make package
Start the daemon as root (rootless will be supported in the future if this project takes off)
./bin/k3c daemon --group=$(id -g) --bootstrap-image=docker.io/rancher/k3c:dev
Run containers like you would with docker
$ ./bin/k3c --help
NAME:
k3c - Lightweight local container platform
USAGE:
k3c [global options] command [command options] [arguments...]
VERSION:
dev (HEAD)
COMMANDS:
create Create a new container
attach Attach local standard input, output, and error streams to a running container
stop Stop one or more running containers
start Start one or more stopped containers
logs Fetch the logs of a container
rm Remove one or more containers
exec Run a command in a running container
run Run a command in a new container
ps List containers
build Build an image from a Dockerfile
images List images
tag Create a tag TARGET_IMAGE that refers to SOURCE_IMAGE
pull Pull an image or a repository from a registry
rmi Remove one or more images
push Push an image or a repository to a registry
inspect Return low-level information on k3c objects
events Get real time events from the server
daemon Run the container daemon
volume, volumes, v Manage volumes
help, h Shows a list of commands or help for one command
Right now this is just an experiment. If there is sufficient interest I expect I'll integrate
k3s
+ k3c
+ k3os
+ k3d
to create a full k3
end to end container solution that will
fully encompass all aspects of the container development life cycle.
Windows and macOS can be fully supported to in the future.
Copyright (c) 2014-2020 Rancher Labs, Inc.
Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at
https://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.