footloose creates containers that look like virtual machines. Those
containers run systemd as PID 1 and a ssh daemon that can be used to login
into the container. Such "machines" behave very much like a VM, it's even
possible to run dockerd in them :)
footloose can be used for a variety of tasks, wherever you'd like virtual
machines but want fast boot times or need many of them. An easy way to think
about it is: Vagrant, but with containers.
footloose in action:
footloose binaries can be downloaded from the release page:
curl -Lo footloose https://github.com/weaveworks/footloose/releases/download/0.3.0/footloose-0.3.0-linux-x86_64
chmod +x footloose
sudo mv footloose /usr/local/bin/On macOS we provide a direct download and a homebrew tap:
curl --silent --location https://github.com/weaveworks/footloose/releases/download/0.3.0/footloose-0.3.0-darwin-x86_64.tar.gz | tar xz
sudo mv footloose /usr/local/binor
brew tap weaveworks/tap
brew install weaveworks/tap/footlooseAlternatively, build and install footloose from source. It requires having
go >= 1.11 installed:
GO111MODULE=on go get github.com/weaveworks/footloosefootloose reads a description of the Cluster of Machines to create from a
file, by default named footloose.yaml. The config command helps with
creating the initial config file:
# Create a footloose.yaml config file. Instruct we want to create 3 machines.
footloose config create --replicas 3Start the cluster:
$ footloose create
INFO[0000] Pulling image: quay.io/footloose/centos7 ...
INFO[0007] Creating machine: cluster-node0 ...
INFO[0008] Creating machine: cluster-node1 ...
INFO[0008] Creating machine: cluster-node2 ...It only takes a second to create those machines. The first time
createruns, it will pull the docker image used by thefootloosecontainers so it will take a tiny bit longer.
SSH into a machine with:
$ footloose ssh root@node1
[root@1665288855f6 ~]# ps fx
PID TTY STAT TIME COMMAND
1 ? Ss 0:00 /sbin/init
23 ? Ss 0:00 /usr/lib/systemd/systemd-journald
58 ? Ss 0:00 /usr/sbin/sshd -D
59 ? Ss 0:00 \_ sshd: root@pts/1
63 pts/1 Ss 0:00 \_ -bash
82 pts/1 R+ 0:00 \_ ps fx
62 ? Ss 0:00 /usr/lib/systemd/systemd-logindfootloose will default to running a centos 7 container image. The --image
argument of config create can be used to configure the OS image. Valid OS
images are:
quay.io/footloose/centos7quay.io/footloose/fedora29quay.io/footloose/ubuntu16.04quay.io/footloose/ubuntu18.04quay.io/footloose/amazonlinux2quay.io/footloose/debian10quay.io/footloose/clearlinux
For example:
footloose config create --replicas 3 --image quay.io/footloose/fedora29Ubuntu images need the --privileged flag:
footloose config create --replicas 1 --image quay.io/footloose/ubuntu16.04 --privilegedfootloose config create creates a footloose.yaml configuration file that is then
used by subsequent commands such as create, delete or ssh. If desired,
the configuration file can be named differently and supplied with the
-c, --config option.
$ footloose config create --replicas 3
$ cat footloose.yaml
cluster:
name: cluster
privateKey: cluster-key
machines:
- count: 3
spec:
image: quay.io/footloose/centos7
name: node%d
portMappings:
- containerPort: 22This configuration can naturally be edited by hand. The full list of available parameters are in the reference documentation.
Interesting things can be done with footloose!
To run dockerd inside a docker container, two things are needed:
- Run the container as privileged (we could probably do better! expose capabilities instead!).
- Mount
/var/lib/dockeras volume, here an anonymous volume. This is because of a limitations of what you can do with the overlay systems docker is setup to use.
cluster:
name: cluster
privateKey: cluster-key
machines:
- count: 1
spec:
image: quay.io/footloose/centos7
name: node%d
portMappings:
- containerPort: 22
privileged: true
volumes:
- type: volume
destination: /var/lib/dockerYou can then install and run docker on the machine:
$ footloose create
$ footloose ssh root@node0
# yum install -y docker iptables
[...]
# systemctl start docker
# docker run busybox echo 'Hello, World!'
Hello, World!Under the hood, Container Machines are just containers. They can be
inspected with docker:
$ docker ps
CONTAINER ID IMAGE COMMAND NAMES
04c27967f76e quay.io/footloose/centos7 "/sbin/init" cluster-node2
1665288855f6 quay.io/footloose/centos7 "/sbin/init" cluster-node1
5134f80b733e quay.io/footloose/centos7 "/sbin/init" cluster-node0The container names are derived from cluster.name and
cluster.machines[].name.
They run systemd as PID 1, it's even possible to inspect the boot messages:
$ docker logs cluster-node1
systemd 219 running in system mode.
Detected virtualization docker.
Detected architecture x86-64.
Welcome to CentOS Linux 7 (Core)!
Set hostname to <1665288855f6>.
Initializing machine ID from random generator.
Failed to install release agent, ignoring: File exists
[ OK ] Created slice Root Slice.
[ OK ] Created slice System Slice.
[ OK ] Reached target Slices.
[ OK ] Listening on Journal Socket.
[ OK ] Reached target Local File Systems.
Starting Create Volatile Files and Directories...
[ OK ] Listening on Delayed Shutdown Socket.
[ OK ] Reached target Swap.
[ OK ] Reached target Paths.
Starting Journal Service...
[ OK ] Started Create Volatile Files and Directories.
[ OK ] Started Journal Service.
[ OK ] Reached target System Initialization.
[ OK ] Started Daily Cleanup of Temporary Directories.
[ OK ] Reached target Timers.
[ OK ] Listening on D-Bus System Message Bus Socket.
[ OK ] Reached target Sockets.
[ OK ] Reached target Basic System.
Starting OpenSSH Server Key Generation...
Starting Cleanup of Temporary Directories...
[ OK ] Started Cleanup of Temporary Directories.
[ OK ] Started OpenSSH Server Key Generation.
Starting OpenSSH server daemon...
[ OK ] Started OpenSSH server daemon.
[ OK ] Reached target Multi-User System.In principle yes, but it will also work with Docker container images and on MacOS as well.
We are a very friendly community and love questions, help and feedback.
If you have any questions, feedback, or problems with footloose:
- Check out the examples.
- Join the discussion
- Invite yourself to the Weave community Slack.
- Ask a question on the #general Slack channel.
- Join the Weave User Group and get invited to online talks, hands-on training and meetups in your area.
- File an issue.
Your feedback is always welcome!