Containerized Footloose
footloose is a CLI tool that creates containers that look like virtual machines.
$ docker run -v /Users/alice/footloose-config:/footloose -v /var/run/docker.sock:/var/run/docker.sock --rm footloose:latest create
time="2021-03-21T16:06:15Z" level=info msg="Docker Image: quay.io/footloose/ubuntu16.04 present locally"
time="2021-03-21T16:06:15Z" level=info msg="Creating machine: cluster-node0 ..."
$ docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
b92f614fef2d quay.io/footloose/ubuntu16.04 "/sbin/init" 4 seconds ago Up 4 seconds 0.0.0.0:8180->8180/tcp, 0.0.0.0:8888->8888/tcp, 0.0.0.0:51641->22/tcp cluster-node0
$ docker run -v /Users/alice/footloose-config:/footloose -v /var/run/docker.sock:/var/run/docker.sock --rm footloose:latest delete
time="2021-03-21T16:07:16Z" level=info msg="Machine cluster-node0 is started, stopping and deleting machine..."
$ docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
docker-footloose is mostly intended for CI or testing automation where you don't want to require agents or local machines to have footloose installed.
Footloose ultimately creates docker containers. In order to containerized footloose (Inception incoming), the Dockerfile is based in Docker in Docker, dind, to be able to interact with the Docker API. As we want to create Docker containers in the host, and not on the contained derived from this image, we need to bind the host docker.sock when running the container -v /var/run/docker.sock:/var/run/docker.sock.
Footloose config where things like the OS image to be used or the exposed ports are defined should be located in a volume mapped to /footloose (that's the WORKDIR in the container), e.g. -v /Users/alice/footloose-config:/footloose. That means that whatever is writte into that folder will be available in the host, such as the cluster-key and cluster-key.pub. I didn't manage to get working things like footloose ssh, but it might be doable. If you need to do so, you could simply do docker exec -it cluster-node0 bash